Astrophysics
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New submissions for Wed, 22 Jan 20
- [1] arXiv:2001.06489 [pdf, other]
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Title: Dynamical self-friction: how mass loss slows you downComments: Submitted to MNRASSubjects: Astrophysics of Galaxies (astro-ph.GA)
We investigate dynamical self-friction, the process by which material that is stripped from a subhalo torques its remaining bound remnant, which causes it to lose orbital angular momentum. By running idealized simulations of a subhalo orbiting within an analytical host halo potential, we isolate the effect of self-friction from traditional dynamical friction due to the host halo. While at some points in a subhalo's orbit the torque of the stripped material can boost the orbital angular momentum of the remnant, the net effect over the long term is orbital decay regardless of the initial orbital parameters or subhalo mass. In order to quantify the strength of self-friction, we run a suite of simulations spanning typical host-to-subhalo mass ratios and orbital parameters. We find that the time-scale for self-friction, defined as the exponential decay time of the subhalo's orbital angular momentum, scales with mass ratio and orbital circularity similar to standard dynamical friction. The decay time due to self-friction is roughly an order of magnitude longer, suggesting that self-friction only contributes at the 10 percent level. However, along more radial orbits, self-friction can occasionally dominate over dynamical friction close to pericentric passage, where mass stripping is intense. This is also the epoch at which the self-friction torque undergoes large and rapid changes in both magnitude and direction, indicating that self-friction is an important process to consider when modeling pericentric passages of subhaloes and their associated satellite galaxies.
- [2] arXiv:2001.06491 [pdf, other]
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Title: Supermassive Star Formation via Super Competitive Accretion in Slightly Metal-enriched CloudsComments: 10 pages, 6figures, submitted to MNRASSubjects: Astrophysics of Galaxies (astro-ph.GA); Solar and Stellar Astrophysics (astro-ph.SR)
Direct collapse black hole (DCBH) formation with mass $\gtrsim 10^{5}~M_{\odot}$ is a promising scenario for the origin of high-redshift supermassive black holes. It has usually been supposed that the DCBH can only form in the primordial gas since the metal enrichment enhances the cooling ability and causes the fragmentation into smaller pieces. What actually happens in such an environment, however, has not been explored in detail. Here, we study the impact of the metal enrichment on the clouds, conducting hydrodynamical simulations to follow the cloud evolution in cases with different degree of the metal enrichment $Z/Z_{\odot}=10^{-6}-10^{-3}$. Below $Z/Z_{\odot}=10^{-6}$, metallicity has no effect and supermassive stars form along with a small number of low-mass stars. With more metallicity $Z/Z_{\odot} \gtrsim 5 \times 10^{-6}$, although the dust cooling indeed promotes fragmentation of the cloud core and produces about a few thousand low-mass stars, the accreting flow preferentially feeds the gas to the central massive stars, which grows supermassive as in the primordial case. We term this formation mode as the {\it super competitive accretion}, where only the central few stars grow supermassive while a large number of other stars are competing for the gas reservoir. Once the metallicity exceeds $10^{-3}~Z_{\odot}$ and metal-line cooling becomes operative, the central star cannot grow supermassive due to lowered accretion rate. Supermassive star formation by the super competitive accretion opens up a new window for seed BHs, which relaxes the condition on metallicity and enhances the seed BH abundance.
- [3] arXiv:2001.06492 [pdf, other]
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Title: On the origin of GW190425Comments: 8 pages, 3 figuresSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc)
The LIGO/Virgo collaborations recently announced the detection of a likely binary neutron star merger, GW190425. The total mass of GW190425 is significantly larger than the masses of Galactic double neutron stars known through radio astronomy. This suggests that the source of GW190425 has a formation history that differs from that of Galactic double neutron stars. We hypothesize that GW190425 formed via unstable "case BB" mass transfer. According to this hypothesis, the progenitor of GW190425 was a binary consisting of a neutron star and a ${\sim}\unit[4-5]{M_\odot}$ helium star, which underwent a common-envelope process. Following the supernovae of the helium star core, a tight, eccentric, double neutron star was formed, which merged in ${\lesssim}\unit[10]{Myr}$. The helium star progenitor may explain the unusually large mass of GW190425, while the short time to merger may explain why we do not see similar systems in radio. In order to test this hypothesis, we measure the eccentricity of GW190425 using publicly available LIGO/Virgo data. We constrain the eccentricity at $\unit[10]{Hz}$ to be $e \leq 0.007$ with $90\%$ confidence. This result provides no evidence for or against the unstable mass transfer scenario because the binary is likely to have circularized to $e\lesssim10^{-4}$ by the time it entered the LIGO/Virgo band. Future detectors operating in lower frequency bands will enable us to discern the formation channel of mergers similar to GW190425 using eccentricity measurements.
- [4] arXiv:2001.06494 [pdf, other]
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Title: Turbulence in stratified atmospheres: implications for the intracluster mediumComments: 15 pages, 12 figures, submitted to MNRAS, comments are welcome. For simulation movies see: this https URLSubjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO); Atmospheric and Oceanic Physics (physics.ao-ph); Fluid Dynamics (physics.flu-dyn)
The gas motions in the intracluster medium (ICM) are governed by stratified turbulence. Stratified turbulence is fundamentally different from Kolmogorov (isotropic, homogeneous) turbulence; kinetic energy not only cascades from large to small scales, but it is also converted into buoyancy potential energy. To understand the density and velocity fluctuations in the ICM, we conduct high-resolution ($1024^2\times 1536$ grid points) hydrodynamical simulations of subsonic turbulence (with rms Mach number $\mathcal{M}\approx 0.25$) and different levels of stratification, quantified by the Richardson number $\mathrm{Ri}$, from $\mathrm{Ri}=0$ (no stratification) to $\mathrm{Ri}=13$ (strong stratification). We quantify the density, pressure and velocity fields for varying stratification because observational studies often use surface brightness fluctuations to infer the turbulent gas velocities of the ICM. We find that the standard deviation of the logarithmic density fluctuations ($\sigma_s$), where $s=\ln(\rho/\left<\rho(z)\right>)$, increases with $\mathrm{Ri}$. For weakly stratified subsonic turbulence ($\mathrm{Ri}\lesssim10$, $\mathcal{M}<1$), we derive a new $\sigma_s$--$\mathcal{M}$--$\mathrm{Ri}$ relation, $\sigma_s^2=\ln(1+b^2\mathcal{M}^4+0.09\mathcal{M}^2\mathrm{Ri}H_P/H_S)$, where $b=1/3$--$1$ is the turbulence driving parameter, and $H_P$ and $H_S$ are the pressure and entropy scale heights respectively. We further find that the power spectrum of density fluctuations, $P(\rho_k/\left<\rho\right>)$, increases in magnitude with increasing $\mathrm{Ri}$, whereas the velocity power spectrum is invariant. Thus, the ratio between density and velocity power spectra strongly depends on $\mathrm{Ri}$. Pressure fluctuations, on the other hand, are independent of stratification and only depend on $\mathcal{M}$.
- [5] arXiv:2001.06497 [pdf, other]
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Title: The cosmic recombination history in light of EDGES measurements of the cosmic dawn 21-cm signalComments: 7 pages, 4 figures, Submitted (comments are welcome)Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
The recent EDGES measurements of the global 21-cm signal from the cosmic dawn suggest that the kinetic temperature of the inter-galactic medium (IGM) might be significantly lower compared to its expected value. The colder IGM directly affects the hydrogen recombination of the universe during the cosmic dawn and dark ages by enhancing the rate of recombinations. Here, we study and quantify, the impact of the colder IGM scenario on the recombination history of the universe in the context of DM-baryonic interaction model which is widely used to explain the EDGES 21-cm signal. We find that, in general, the hydrogen ionisation fraction gets suppressed during the dark ages and cosmic dawn and the suppression gradually increases at lower redshifts. However, accurate estimation of the ionisation fraction requires knowledge of the entire thermal history of the IGM, from the thermal decoupling of hydrogen gas and the CMBR to the cosmic dawn. It is possible that two separate scenarios which predict very similar HI differential temperature during the cosmic dawn and are consistent with the EDGES 21-cm signal might have very different IGM temperature during the dark ages. The evolutions of the ionization fraction in these two scenarios are quite different. This prohibits us to accurately calculate the ionisation fraction during the cosmic dawn using the EDGES 21-cm signal alone. We find that the changes in the ionisation fraction w.r.t the standard scenario at redshift $z \sim 17 $ could be anything between $\sim 0 \%$ to $\sim 36 \%$. This uncertainty remains even for a more precise measurement of the 21-cm signal from the cosmic dawn. However, the IGM temperature measured at two widely separated epochs should be able to constrain the ionisation fraction more accurately.
- [6] arXiv:2001.06498 [pdf, other]
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Title: Long-Period High-Amplitude Red Variables in the KELT SurveyAuthors: R. Alex Arnold, M. Virginia McSwain, Joshua Pepper, Patricia A. Whitelock, Nina Hernitschek, David J. James, Rudolf B. Kuhn, Michael B. Lund, Joseph E. Rodriguez, Robert J. Siverd, Keivan G. StassunComments: Accepted to ApJSSubjects: Solar and Stellar Astrophysics (astro-ph.SR)
We present a sample of 4,132 Mira-like variables (red variables with long periods and high amplitudes) in the Kilodegree Extremely Little Telescope (KELT) survey. Of these, 814 are new detections. We used 2MASS colors to identify candidate asymptotic giant branch (AGB) stars. We tested for photometric variability among the sample and used Lomb-Scargle to determine the periodicity of the variable sample. We selected variables with high amplitudes and strong periodic behavior using a Random Forest classifier. Of the sample of 4,132 Mira-like variables, we estimate that 70% are Miras, and 30% are semi-regular (SR) variables. We also adopt the method of using (W_{RP} - W_{K_s}) vs. (J - K_s) colors (Lebzelter et al. 2018) in distinguishing between O-rich and C-rich Miras and find it to be an improvement over 2MASS colors.
- [7] arXiv:2001.06501 [pdf, other]
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Title: The better half -- Asymmetric star-formation due to ram pressure in the EAGLE simulationsAuthors: P. Troncoso-Iribarren, N. Padilla, C. Santander, C.D.P. Lagos, D. García-Lambas, S. Rodriguez, S. ContrerasSubjects: Astrophysics of Galaxies (astro-ph.GA)
We use the EAGLE simulations to study the effects of the intra-cluster medium (ICM) on the spatially resolved star-formation activity in galaxies. We study three cases of galaxy asymmetry dividing each galaxy in two halves using the plane (i) perpendicular to the $\rm \texttt{velocity}$ direction, differentiating the galaxy part approaching to the cluster center, hereafter dubbed as the "leading half", and the opposite one "trailing half", (ii) perpendicular to the $\rm \texttt{radial}$ position of the satellite to the centre of the cluster, (iii) that maximizes the star-formation rate ($\rm SFR$) difference between the two halves. For (i), we find an enhancement of the $\rm SFR$, star formation efficiency ($\rm SFE$), and interstellar medium pressure in the leading half with respect to the trailing one and normal star-forming galaxies in the EAGLE simulation, and a clear overabundance of gas particles in their trailing. These results suggest that ram pressure (RP) is boosting the star formation by gas compression in the leading half, and transporting the gas to the trailing half. This effect is more pronounced in satellites of intermediate stellar masses $\rm 10^{9.5-10.5} M_{\odot}$, with gas masses above $\rm 10^{9} M_{\odot}$, and located within one virial radius or in the most massive clusters. In (iii) we find an alignment between the velocity and the vector perpendicular to the plane that maximizes the $\rm SFR$ difference between the two halves. It suggests that finding this plane in real galaxies can provide insights into the velocity direction.
- [8] arXiv:2001.06512 [pdf, other]
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Title: Multiwavelength behaviour of the blazar 3C279: decade-long study from $γ$-ray to radioAuthors: V.M. Larionov, S.G. Jorstad, A.P. Marscher, M. Villata, C.M. Raiteri, P.S. Smith, I. Agudo, S.S. Savchenko, D.A. Morozova, J.A. Acosta-Pulido, M.F. Aller, H.D. Aller, T.S. Andreeva, A.A. Arkharov, R. Bachev, G. Bonnoli, G.A. Borman, V. Bozhilov, P. Calcidese, M.I. Carnerero, D. Carosati, C. Casadio, W.-P. Chen, G. Damljanovic, A.V. Dementyev, A. Di Paola, A. Frasca, A. Fuentes, J.L. Gómez, P. Gónzalez-Morales, A. Giunta, T.S. Grishina, M.A. Gurwell, V.A. Hagen-Thorn, T. Hovatta, S. Ibryamov, M. Joshi, S. Kiehlmann, J.-Y. Kim, G. N. Kimeridze, E.N. Kopatskaya, Yu.A. Kovalev, Y.Y. Kovalev, O.M. Kurtanidze, S.O. Kurtanidze, A. Lähteenmäki, C. Lázaro, L.V. Larionova, E.G. Larionova, G. Leto, A. Marchini, K. Matsumoto, B. Mihov, M. Minev, M.G. Mingaliev, D. Mirzaqulov, et al. (31 additional authors not shown)Comments: 21 pages, 18 figures, accepted for publication in MNRASSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); Astrophysics of Galaxies (astro-ph.GA)
We report the results of decade-long (2008-2018) $\gamma$-ray to 1 GHz radio monitoring of the blazar 3C 279, including GASP/WEBT, $\it{Fermi}$ and $\it{Swift}$ data, as well as polarimetric and spectroscopic data. The X-ray and $\gamma$-ray light curves correlate well, with no delay > 3 hours, implying general co-spatiality of the emission regions. The $\gamma$-ray-optical flux-flux relation changes with activity state, ranging from a linear to a more complex dependence. The behaviour of the Stokes parameters at optical and radio wavelengths, including 43 GHz VLBA images, supports either a predominantly helical magnetic field or motion of the radiating plasma along a spiral path. Apparent speeds of emission knots range from 10 to 37c, with the highest values requiring bulk Lorentz factors close to those needed to explain $\gamma$-ray variability on very short time scales. The Mg II emission line flux in the `blue' and `red' wings correlates with the optical synchrotron continuum flux density, possibly providing a variable source of seed photons for inverse Compton scattering. In the radio bands we find progressive delays of the most prominent light curve maxima with decreasing frequency, as expected from the frequency dependence of the $\tau=1$ surface of synchrotron self-absorption. The global maximum in the 86 GHz light curve becomes less prominent at lower frequencies, while a local maximum, appearing in 2014, strengthens toward decreasing frequencies, becoming pronounced at $\sim5$ GHz. These tendencies suggest different Doppler boosting of stratified radio-emitting zones in the jet.
- [9] arXiv:2001.06514 [pdf, ps, other]
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Title: QSO photometric redshifts from SDSS, WISE and GALEX coloursAuthors: S. J. CurranComments: Accepted by MNRASSubjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Astrophysics of Galaxies (astro-ph.GA)
Machine learning techniques, specifically the k-nearest neighbour algorithm applied to optical band colours, have had some success in predicting photometric redshifts of quasi-stellar objects (QSOs): Although the mean of differences between the spectroscopic and photometric redshifts is close to zero, the distribution of these differences remains wide and distinctly non-Gaussian. As per our previous empirical estimate of photometric redshifts, we find that the predictions can be significantly improved by adding colours from other wavebands, namely the near-infrared and ultraviolet. Self-testing this, by using half of the 33 643 strong QSO sample to train the algorithm, results in a significantly narrower spread for the remaining half of the sample. Using the whole QSO sample to train the algorithm, the same set of magnitudes return a similar spread for a sample of radio sources (quasars). Although the matching coincidence is relatively low (739 of the 3663 sources having photometry in the relevant bands), this is still significantly larger than from the empirical method (2%) and thus may provide a method with which to obtain redshifts for the vast number of continuum radio sources expected to be detected with the next generation of large radio telescopes.
- [10] arXiv:2001.06526 [pdf, other]
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Title: Optimization of Radio Array Telescopes to Search for Fast RadioBurstsSubjects: Instrumentation and Methods for Astrophysics (astro-ph.IM)
We present projected Fast Radio Burst detection rates from surveys carried out using a set of hypothetical close-packed array telescopes. The cost efficiency of such a survey falls at least as fast as the inverse square of the survey frequency. There is an optimum array element effective area in the range 0 to 25 $\rm{m^2}$. If the power law index of the FRB integrated source count versus fluence $\alpha = d ~ln R/d ~ln F > -1$ the most cost effective telescope layout uses individual dipole elements, which provides an all-sky field of view. If $\alpha <-1$ dish arrays are more cost effective.
- [11] arXiv:2001.06531 [pdf, other]
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Title: Forming Diverse Super-Earth Systems in SituComments: 18 pages, 9 figures. Submitted to ApJ; revised in response to referee reportSubjects: Earth and Planetary Astrophysics (astro-ph.EP)
Super-Earths and mini-Neptunes exhibit great diversity in their compositional and orbital properties. Their bulk densities span a large range, from those dense enough to be purely rocky to those needing a substantial contribution from volatiles to their volumes. Their orbital configurations range from compact, circular multi-transiting systems like Kepler-11 to systems like our Solar System's terrestrial planets with wider spacings and modest but significant eccentricities and mutual inclinations. Here we investigate whether a continuum of formation conditions resulting from variation in the amount of solids available in the inner disk can account for the diversity of orbital and compositional properties observed for super Earths, including the apparent dichotomy between single transiting and multiple transiting system. We simulate in situ formation of super-Earths via giant impacts and compare to the observed Kepler sample. We find that intrinsic variations among disks in the amount of solids available for in situ formation can account for the orbital and compositional diversity observed among Kepler's transiting planets. Our simulations can account for the planets' distributions of orbital period ratios, transit duration ratios, and transit multiplicity; higher eccentricities for single than multi transiting planets; smaller eccentricities for larger planets; scatter in the mass-radius relation, including lower densities for planets with masses measured with TTVs than RVs; and similarity in planets' sizes and spacings within each system. Our findings support the theory that variation among super-Earth and mini-Neptune properties is primarily locked in by different in situ formation conditions, rather than arising stochastically through subsequent evolution.
- [12] arXiv:2001.06532 [pdf, other]
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Title: Fountains and storms: The role of AGN and mergers in disrupting the cool-core in the RomulusC simulationComments: 16 pages, 9 figuresSubjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
The intracluster medium (ICM) is a multi-phase environment, dynamically regulated by Active Galactic Nuclei (AGN), the motions of galaxies through it, and mergers with other clusters. AGN as a central heating source are key to preventing runaway cooling flows, but their role in heating cores in a cosmological context is still poorly understood. The activity of the AGN is strongly linked to star formation, especially in the Brightest Cluster Galaxy (BCG), likely because both rely on cold phase gas. A self-consistent model for AGN and star formation in galaxy clusters thus requires cosmological context, higher resolution, and a careful modeling of cooling and heating balance. In this paper, we use the high-resolution hydrodynamical cosmological simulation of the RomulusC galaxy cluster to study in detail the role of AGN and a major, head-on merger in shaping the cluster core. The unprecedented resolution of the RomulusC simulation captures the multiphase structure of the ICM. The realistic large-scale outflows launched by very small-scale thermal injections, the improved modeling of turbulent diffusion and mixing, and the particle nature of the simulation allow us to carefully separate different heating channels. We show that AGN activity, while efficient at regulating star formation, is incapable of destroying a CC. Instead, that process is facilitated by a head-on, 1:8 mass ratio merger. The merger generates bulk and turbulent motions, which in turn mix high entropy gas generated by AGN and merger driven shocks, turbulent dissipation and sloshing of the ICM by infalling substructures. While central cooling times remain shorter than the Hubble time, restoring a CC is made more difficult by the reduced precipitation rates at larger radii, emphasizing that the AGN-ICM connection is truly a multi-scale problem.
- [13] arXiv:2001.06551 [pdf, other]
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Title: Optical follow-up of gravitational wave triggers with DECam during the first two LIGO/VIRGO observing runsAuthors: K. Herner (1), J. Annis (1), D. Brout (2 and 3), M. Soares-Santos (4 and 1), R. Kessler (5), M. Sako (2), R. Butler (1 and 5), Z. Doctor (5), A. Palmese (1 and 6), S. Allam (1), D. L. Tucker (1), F. Sobreira (7 and 8), B. Yanny (1), H. T. Diehl (1), J. Frieman (1 and 5), N. Glaeser (1 and 9), A. Garcia (4), N. Sherman (1 and 10), K. Bechtol (11 and 12), E. Berger (13), H. Y. Chen (13 and 5), C. J. Conselice (14), E. Cook (15), P. S. Cowperthwaite (13), T. M. Davis (16), A. Drlica-Wagner (1), B. Farr (5), D. Finley (1), R. J. Foley (17), J. Garcia-Bellido (18), M. S. S. Gill (19), R. A. Gruendl (20 and 21), D. E. Holz (5), N. Kuropatkin (1), H. Lin (1), J. Marriner (1), J. L. Marshall (15), T. Matheson (22), E. Neilsen (1), F. Paz-Chinchón (20 and 21), M. Sauseda (15), D. Scolnic (5), et al. (43 additional authors not shown)Comments: 15 oages, 7 figures, submitted to Astronomy and ComputingSubjects: Instrumentation and Methods for Astrophysics (astro-ph.IM)
Gravitational wave (GW) events detectable by LIGO and Virgo have several possible progenitors, including black hole mergers, neutron star mergers, black hole--neutron star mergers, supernovae, and cosmic string cusps. A subset of GW events are expected to produce electromagnetic (EM) emission that, once detected, will provide complementary information about their astrophysical context. To that end, the LIGO--Virgo Collaboration (LVC) sends GW candidate alerts to the astronomical community so that searches for their EM counterparts can be pursued. The DESGW group, consisting of members of the Dark Energy Survey (DES), the LVC, and other members of the astronomical community, uses the Dark Energy Camera (DECam) to perform a search and discovery program for optical signatures of LVC GW events. DESGW aims to use a sample of GW events as standard sirens for cosmology. Due to the short decay timescale of the expected EM counterparts and the need to quickly eliminate survey areas with no counterpart candidates, it is critical to complete the initial analysis of each night's images as quickly as possible. We discuss our search area determination, imaging pipeline, and candidate selection processes. We review results from the DESGW program during the first two LIGO--Virgo observing campaigns and introduce other science applications that our pipeline enables.
- [14] arXiv:2001.06558 [pdf, other]
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Title: Simplified 3D GCM modelling of the irradiated brown dwarf WD0137-349BAuthors: Graham K.H. Lee, Sarah L. Casewell, Katy L. Chubb, Mark Hammond, Xianyu Tan, Shang-Min Tsai, Raymond T. PierrehumbertComments: Submitted to MNRAS - Comments from the community are welcomeSubjects: Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)
Context: White dwarf - Brown dwarf short period binaries (P$_{\rm orb}$ $\lesssim$ 2 hours) are some of the most extreme irradiated atmospheric environments known. These systems offer an opportunity to explore theoretical and modelling efforts of irradiated atmospheres different to typical hot Jupiter systems. Aims: We aim to investigate the three dimensional atmospheric structural and dynamical properties of the Brown dwarf WD0137-349B. Methods: We use the three dimensional GCM model Exo-FMS, with a dual-band grey radiative-transfer scheme to model the atmosphere of WD0137-349B. The results of the GCM model are post-processed using the three dimensional Monte Carlo radiative-transfer model CMCRT. Results: Our results suggest inefficient day-night energy transport and a large day-night temperature contrast for WD0137-349B. Multiple flow patterns are present, shifting energy asymmetrically eastward or westward depending on their zonal direction and latitude. Regions of Hadley-like overturning are produced on the western terminator. We are able to reproduce the observed start of the systems near-IR emission excess at $\gtrsim$ 1.95 $\mu$m. Our model over predicts the IR phase curve fluxes by factors of $\approx$1-3, but generally fits the shape of the phase curves well. Conclusions: We present a first attempt at simulating the atmosphere of a short period White dwarf - Brown dwarf binary in a 3D setting. Further studies into the radiative and photochemical heating from the UV irradiation is required to more accurately capture the energy balance inside the Brown dwarf atmosphere. Cloud formation may also play an important role in shaping the emission spectra of the Brown dwarf.
- [15] arXiv:2001.06560 [pdf, other]
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Title: Do model emission line galaxies live in filaments at z~1?Authors: V. Gonzalez-Perez (LJMU), W. Cui (ROE), S. Contreras (DIPC), C. M. Baugh (ICC), J. Comparat (MPE), A. J. Griffin (ICC), J. Helly (ICC), A. Knebe (UAM), C. Lacey (ICC), P. Norberg (ICC)Comments: 16 pages plus appendixes, 17 figures, submitted to MNRASSubjects: Astrophysics of Galaxies (astro-ph.GA)
Current and future cosmological surveys are targeting star-forming galaxies at z~1 with nebular emission lines. In this work we use a state-of-the-art model of galaxy formation and evolution to explore the large scale environment of star-forming emission line galaxies (ELGs). Model galaxies are selected with cuts such that the samples can be directly compared with the DEEP2, VVDS, eBOSS-SGC and DESI surveys. Their large scale environment have been classified using a velocity-shear-tensor and a tidal-tensor algorithms. Half of model ELGs live in filaments and about a third in sheets. Model ELGs in knots have the largest satellite fractions. We find that the shape of the mean halo occupation distribution of model ELGs varies widely for different large scale environments. To put these results in context, we have compared fixed number density samples of galaxies, generated by either imposing an extra cut in stellar mass, star formation rate (SFR) or L[OII] to the ELGs, or by imposing a single cut in these quantities to the total model galaxy population. For the fixed number density samples, ELGs are close to L[OII] and SFR selected samples for densities above $10^{-4.2}h^{3}{\rm Mpc}^{-3}$. ELGs with an extra cut in stellar mass to fix their number density, present differences in sheets and knots with respect to the other samples. ELGs, SFR and L[OII] selected samples with equal number density, have similar large scale bias but their clustering below separations of $1h^{-1}$Mpc is different.
- [16] arXiv:2001.06589 [pdf, other]
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Title: First detection of the 448 GHz ortho-H2O line at high redshift: probing the structure of a starburst nucleus at z = 3.63Authors: C. Yang (1), E. González-Alfonso (2), A. Omont (3), M. Pereira-Santaella (4), J. Fischer (5), A. Beelen (6), R. Gavazzi (3) ((1) ESO Chile, (2) Universidad de Alcalá, (3) IAP, (4) CSIC-INTA, (5) GMU, (6) IAS-Orsay)Comments: 1 table and 4 figures, A&A Letter acceptedSubjects: Astrophysics of Galaxies (astro-ph.GA)
Submillimeter rotational lines of H2O are a powerful probe in warm gas regions of the ISM, tracing scales and structures ranging from kpc disks to the most compact and dust-obscured regions of galactic nuclei. The ortho-H2O(423-330) line at 448 GHz, which was recently detected in a local luminous infrared galaxy (Pereira-Santaella et al. 2017), offers a unique constraint on the excitation conditions and ISM properties in deeply buried galaxy nuclei since the line requires high far-IR optical depths to be excited. In this letter, we report the first high-redshift detection of the 448 GHz H2O(423-330) line using ALMA, in a strongly lensed submillimeter galaxy (SMG) at z=3.63. After correcting for magnification, the luminosity of the 448 GHz H2O line is ~10^6 L_sun. In combination with three other previously detected H2O lines, we build a model that "resolves" the dusty ISM structure of the SMG, and find that it is composed of a ~1 kpc optically thin (optical depth at 100{\mu}m {\tau}_{100}~0.3) disk component with dust temperature T_{dust} \approx 50 K emitting a total infrared power of 5e12 L_sun with surface density \Sigma_{IR}=4e11 L_sun kpc^{-2}, and a very compact (0.1 kpc) heavily dust-obscured ({\tau}_{100} \gtrsim 1) nuclear core with very warm dust (100 K) and \Sigma_{IR}=8e12 L_sun kpc^{-2}. The H2O abundance in the core component, X_{H2O}~(0.3-5)e{-5}, is at least one order of magnitude higher than in the disk component. The optically thick core has the characteristic properties of an Eddington-limited starburst, providing evidence that radiation pressure on dust is capable of supporting the ISM in buried nuclei at high redshifts. The multi-component ISM structure revealed by our models illustrates that dust and molecules such as H2O are present in regions characterized by highly differing conditions and scales, extending from the nucleus to more extended regions of SMGs.
- [17] arXiv:2001.06593 [pdf, other]
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Title: Corroborating pseudoscalar probing model with pulsar polarisation datasetsComments: 7 pages, 5 figures, 3 tables. [EICP2]Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics - Phenomenology (hep-ph)
Recently, we have used, pulsar polarisation datasets, on circular polarisation degree & linear polarisation position angle, to relate with well established theories, on ellipticity parameter and linear polarisation position angles, accrued by unpolarised photons, while undergoing photon-ALP oscillations, inside a magnetised medium. This has given us parameter values such as ALP mass and its coupling to photons. To further test this, we now switch to different wavebands, other than earlier 21 cm wavelength, and check for the validity of our model. Here we use two data sets on circular polarisation degree of identical pulsars observed in two different wavebands. We show, correlation between these two new sets of data and our model using the composite product variable of ALP mass and its coupling to photons, exist. We also check whether our model hypothesis that one physical effect, namely ALP-photon mixing is sufficient to, estimate ALP parameters, faithfully, or not. We conclude by describing other pertinent physical effects that may be included into our model to explain the circular polarisation degree of pulsars, independent of its operating wavelength of observation.
- [18] arXiv:2001.06614 [pdf, other]
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Title: xGASS: Cold gas content and quenching in galaxies below the star forming main sequenceComments: 15 pages, 11 figures, accepted for publication in MNRASSubjects: Astrophysics of Galaxies (astro-ph.GA)
We use HI and H2 global gas measurements of galaxies from xGASS and xCOLD GASS to investigate quenching paths of galaxies below the star formation main sequence (SFMS). We show that the population of galaxies below the SFMS is not a 1:1 match with the population of galaxies below the HI and H2 gas fraction scaling relations. Some galaxies in the transition zone (TZ) 1-sigma below the SFMS can be as HI-rich as those in the SFMS, and have on average longer gas depletion timescales. We find evidence for environmental quenching of satellites, but central galaxies in the TZ defy simple quenching pathways. Some of these so-called "quenched" galaxies may still have significant gas reservoirs and be unlikely to deplete them anytime soon. As such, a correct model of galaxy quenching cannot be inferred with SFR (or other optical observables) alone, but must include observations of the cold gas. We also find that internal structure (particularly, the spatial distribution of old and young stellar populations) plays a significant role in regulating the star formation of gas-rich isolated TZ galaxies, suggesting the importance of bulges in their evolution.
- [19] arXiv:2001.06637 [pdf, ps, other]
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Title: Joint Analysis of Energy and RMS Spectra from MAXI J1535-571 with Insight-HXMTAuthors: L. D. Kong, S. Zhang, Y. P. Chen, L. Ji, S. N. Zhang, Y. R. Yang, L. Tao, X. Ma, J. L. Qu, F. J. Lu, Q. C. Bu, L. Chen, L. M. Song, T. P. Li, Y. P. Xu, X. L. Cao, Y. Chen, C. Z. Liu, C. Cai, Z. Chang, G. Chen, T. X. Chen, Y. B. Chen, W. Cui, W. W. Cui, J. K. Deng, Y. W. Dong, Y. Y. Du, M. X. Fu, G. H. Gao, H. Gao, M. Gao, M. Y. Ge, Y. D. Gu, J. Guan, C. C. Guo, D. W. Han, Y. Huang, J. Huo, S. M. Jia, L. H. Jiang, W. C. Jiang, J. Jin, B. Li, C. K. Li, G. Li, M. S. Li, W. Li, X. Li, X. B. Li, X. F. Li, Y. G. Li, Z. W. Li, X. H. Liang, J. Y. Liao, G. Q. Liu, H. X. Liu, H. W. Liu, S. Z. Liu, X. J. Liu, Y. N. Liu, B. Lu, X. F. Lu, Q. Luo, T. Luo, B. Meng, Y. Nang, J. Y. Nie, G. Ou, X. Q. Ren, N. Sai, X. Y. Song, L. Sun, Y. Tan, Y. L. Tuo, C. Wang, G. F. Wang, J. Wang, P. J. Wang, W. S. Wang, Y. S. Wang, et al. (38 additional authors not shown)Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)
A new black hole X-ray binary (BHXRB) MAXI J1535-571 was discovered by MAXI during its outburst in 2017. Using observations taken by the first Chinese X-ray satellite, the Hard X-ray Modulation Telescope (dubbed as Insight-HXMT), we perform a joint spectral analysis (2-150 keV) in both energy and time domains. The energy spectra provide the essential input for probing the intrinsic Quasi-Periodic Oscillation (QPO) fractional rms spectra (FRS). Our results show that during the intermediate state, the energy spectra are in general consistent with those reported by Swift/XRT and NuSTAR. However, the QPO FRS become harder and the FRS residuals may suggest the presence of either an additional power-law component in the energy spectrum or a turn-over in the intrinsic QPO FRS at high energies.
- [20] arXiv:2001.06656 [pdf, other]
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Title: Rotational properties of Hilda asteroids observed by the K2 missionAuthors: Gyula M. Szabó (1,2), Csaba Kiss (3), Róbert Szakáts (3), András Pál (3,4), László Molnár (3,5), Krisztián Sárneczky (3), József Vinkó (3), Róbert Szabó (3,5), Gábor Marton (3), László L. Kiss (3,6) ((1) ELTE Eötvös Loránd University, Gothard Astrophysical Observatory, Szombathely, Hungary, (2) MTA-ELTE Exoplanet Research Group, Szombathely, Hungary, (3) Konkoly Observatory, Research Centre for Astronomy and Earth Sciences, Budapest, Hungary, (4) Eötvös Loránd University, Budapest, Hungary, (5) MTA CSFK Lendület Near-Field Cosmology Research Group, (6) Sydney Institute for Astronomy, School of Physics A29, University of Sydney, NSW, Australia)Comments: ApJS, in press, 28 pagesSubjects: Earth and Planetary Astrophysics (astro-ph.EP)
Hilda asteroids orbit at the outer edge, or just outside of the Main Belt, occupying the 2:3 mean motion resonance with Jupiter. It is known that the group shows a mixed taxonomy that suggests the mixed origin of Hilda members, having migrated to the current orbit both from the outer Main Belt and from the Trojans swarms. But there are still few observations for comparative studies that help in understanding the Hilda group in deeper details. We identified 125 individual light curves of Hilda asteroids observed by the K2 mission. We found that despite of the mixed taxonomies, the Hilda group highly resembles to the Trojans in the distribution of rotation periods and amplitudes, and even the LR group (mostly C and X-type) Hildas follow this rule. Contrary to the Main Belt, Hilda group lacks the very fast rotators. The ratio of extremely slow rotators (P>100 h) is a surprising 18%, which is unique in the Solar System. The occurrence rate of asteroids with multiple periods (4%) and asteroids with three maxima in the light curves (5%) can be signs of high rate of binarity, which we can estimate as 25% within the Hilda group.
- [21] arXiv:2001.06669 [pdf, other]
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Title: Deep residual detection of radio frequency interference for FASTComments: 12 pages, 16 figures. Accepted for publication in Monthly Notices of the Royal Astronomical SocietyJournal-ref: MNRAS.2020.492(1):1421-1431 https://doi.org/10.1093/mnras/stz3521Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Image and Video Processing (eess.IV)
Radio frequency interference (RFI) detection and excision are key steps in the data-processing pipeline of the Five-hundred-meter Aperture Spherical radio Telescope (FAST). Because of its high sensitivity and large data rate, FAST requires more accurate and efficient RFI flagging methods than its counterparts. In the last decades, approaches based upon artificial intelligence (AI), such as codes using convolutional neural networks (CNNs), have been proposed to identify RFI more reliably and efficiently. However, RFI flagging of FAST data with such methods has often proved to be erroneous, with further manual inspections required. In addition, network construction as well as preparation of training data sets for effective RFI flagging has imposed significant additional workloads. Therefore, rapid deployment and adjustment of AI approaches for different observations is impractical to implement with existing algorithms. To overcome such problems, we propose a model called RFI-Net. With the input of raw data without any processing, RFI-Net can detect RFI automatically, producing corresponding masks without any alteration of the original data. Experiments with RFI-Net using simulated astronomical data show that our model has outperformed existing methods in terms of both precision and recall. Besides, compared with other models, our method can obtain the same relative accuracy with fewer training data, thus reducing the effort and time required to prepare the training data set. Further, the training process of RFI-Net can be accelerated, with overfittings being minimized, compared with other CNN codes. The performance of RFI-Net has also been evaluated with observing data obtained by FAST and the Bleien Observatory. Our results demonstrate the ability of RFI-Net to accurately identify RFI with fine-grained, high-precision masks that required no further modification.
- [22] arXiv:2001.06683 [pdf]
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Title: The Habitable Exoplanet Observatory (HabEx) Mission Concept Study Final ReportAuthors: B. Scott Gaudi, Sara Seager, Bertrand Mennesson, Alina Kiessling, Keith Warfield, Kerri Cahoy, John T. Clarke, Shawn Domagal-Goldman, Lee Feinberg, Olivier Guyon, Jeremy Kasdin, Dimitri Mawet, Tyler Robinson, Leslie Rogers, Paul Scowen, Rachel Somerville, Karl Stapelfeldt, Christopher Stark, Daniel Stern, Margaret Turnbull, Rashied Amini, Gary Kuan, Stefan Martin, Rhonda Morgan, David Redding, H. Philip Stahl, Ryan Webb, Oscar Alvarez-Salazar, William L. Arnold, Manan Arya, Bala Balasubramanian, Mike Baysinger, Ray Bell, Chris Below, Jonathan Benson, Lindsey Blais, Jeff Booth, Robert Bourgeois, Case Bradford, Alden Brewer, Thomas Brooks, Eric Cady, Mary Caldwell, Rob Calvet, Steven Carr, Derek Chan, Velibor Cormarkovic, Keith Coste, Charlie Cox, Rolf Danner, Jacqueline Davis, Larry Dewell, et al. (119 additional authors not shown)Comments: Full report: 498 pages. Executive Summary: 14 pages. More information about HabEx can be found here: this https URLSubjects: Instrumentation and Methods for Astrophysics (astro-ph.IM)
The Habitable Exoplanet Observatory, or HabEx, has been designed to be the Great Observatory of the 2030s. For the first time in human history, technologies have matured sufficiently to enable an affordable space-based telescope mission capable of discovering and characterizing Earthlike planets orbiting nearby bright sunlike stars in order to search for signs of habitability and biosignatures. Such a mission can also be equipped with instrumentation that will enable broad and exciting general astrophysics and planetary science not possible from current or planned facilities. HabEx is a space telescope with unique imaging and multi-object spectroscopic capabilities at wavelengths ranging from ultraviolet (UV) to near-IR. These capabilities allow for a broad suite of compelling science that cuts across the entire NASA astrophysics portfolio. HabEx has three primary science goals: (1) Seek out nearby worlds and explore their habitability; (2) Map out nearby planetary systems and understand the diversity of the worlds they contain; (3) Enable new explorations of astrophysical systems from our own solar system to external galaxies by extending our reach in the UV through near-IR. This Great Observatory science will be selected through a competed GO program, and will account for about 50% of the HabEx primary mission. The preferred HabEx architecture is a 4m, monolithic, off-axis telescope that is diffraction-limited at 0.4 microns and is in an L2 orbit. HabEx employs two starlight suppression systems: a coronagraph and a starshade, each with their own dedicated instrument.
- [23] arXiv:2001.06712 [pdf, other]
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Title: Monitoring the optical quality of the FACT Cherenkov TelescopeAuthors: Laurits TaniSubjects: Instrumentation and Methods for Astrophysics (astro-ph.IM)
In gamma ray astronomy muon events have a distinct feature of casting ring-like images on the sensor plane, thus forming a well known signal class for Cherenkov telescopes. These ring-like images can then be used to deduce the optical point spread function (PSF) which is an important measure of the optical quality of the imaging-reflector. In this thesis the observed 'fuzziness' of muon rings is used as a measure to infer the PSF. However to have a good estimate for this 'fuzziness' parameter, the reconstruction of the ring center and ring radius itself needs to be accurate, so different methods of ring feature extraction are studied. To check for the accuracy of the methods a simulation and analysis is performed. Measuring the evolution of the PSF over time allows to identify its effects and take them into account for the reconstruction of gamma-rays postliminary. As a further benefit of the methods presented here no additional observations are needed to measure the PSF nor any human activity on site is required. The accuracy of the method, and the PSF of FACT vs. time are presented.
- [24] arXiv:2001.06815 [pdf, other]
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Title: The ionic composition of the local absorber towards 3C 273Subjects: Astrophysics of Galaxies (astro-ph.GA)
Hot ionized gas is observed in the local vicinity of our galaxy through spectral absorption features. The most common hypothesis is that this gas forms a halo surrounding our Milky-Way (MW), in collisional ionization equilibrium. In this paper we investigate the elemental abundance of this hot and ionized local gas. We use a 2.4 Ms stacked X-ray spectrum of the bright blazar 3C 273 and probe the local absorption features. Using ion-by-ion fitting of the X-ray absorption lines we derive the column density of each ionization species. Based on the column densities we reconstruct the Absorption measure distribution (AMD), namely the hydrogenic column density as a function of temperature. We report the elemental abundances of C, N, Ne, and Fe relative to solar O. Previous measurements of local X-ray emission lines in conjunction with the present column densities indicate a scale height of $1-80$ kpc and hydrogen number density of $10^{-4}-10^{-3}$cm$^{-3}$ for the hot ionized gas. Additionally, we detect He-like O lines from the quasar broad line region with velocities of 6400$\pm$1500 km s$^{-1}$
- [25] arXiv:2001.06818 [pdf, other]
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Title: The stellar photosphere-hydrogen ionization front interaction in Classical Pulsators: a theoretical explanation for observed period-colour relationsAuthors: Susmita Das, Shashi M. Kanbur, Earl P. Bellinger, Anupam Bhardwaj, Harinder P. Singh, Brett Meerdink, Nicholas Proietti, Anthony Chalmers, Ryan JordanComments: 20 pages, 14 figures. Accepted for publication in MNRASSubjects: Solar and Stellar Astrophysics (astro-ph.SR)
Period-colour and amplitude-colour (PCAC) relations can be used to probe both the hydrodynamics of outer envelope structure and evolutionary status of Cepheids and RR Lyraes. In this work, we incorporate the PCAC relations for RR Lyraes, BL Her, W Vir and classical Cepheids in a single unifying theory that involves the interaction of the hydrogen ionization front (HIF) and stellar photosphere and the theory of stellar evolution. PC relations for RR Lyraes and classical Cepheids using OGLE-IV data are found to be consistent with this theory: RR Lyraes have shallow/sloped relations at minimum/maximum light whilst long-period ($P>10$ days) Cepheids exhibit sloped/flat PC relations at minimum/maximum light. The differences in the PC relations for Cepheids and RR Lyraes can be explained based on the relative location of the HIF and stellar photosphere which changes depending on their position on the HR diagram. We also extend our analysis of PCAC relations for type II Cepheids in the Galactic bulge, LMC and SMC using OGLE-IV data. We find that BL Her stars have sloped PC relations at maximum and minimum light similar to short-period ($P<10$ days) classical Cepheids. W Vir stars exhibit sloped/flat PC relation at minimum/maximum light similar to long-period classical Cepheids. We also compute state-of-the-art 1D radiation hydrodynamic models of RR Lyraes, BL Her and classical Cepheids using the radial stellar pulsation code in MESA to further test these ideas theoretically and find that the models are generally consistent with this picture. We are thus able to explain PC relations at maximum and minimum light across a broad spectrum of variable star types.
- [26] arXiv:2001.06836 [pdf, other]
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Title: Hot Exoplanet Atmospheres Resolved with Transit Spectroscopy (HEARTS) III. Atmospheric structure of the misaligned ultra-hot Jupiter WASP-121bAuthors: V. Bourrier, D. Ehrenreich, M. Lendl, M. Cretignier, R. Allart, X. Dumusque, H.M Cegla, A. Suarez-Mascareno, A. Wyttenbach, H.J. Hoeijmakers, C. Melo, T. Kuntzer, N. Astudillo-Defru, H. Giles, K. Heng, D. Kitzmann, B. Lavie, C. Lovis, F. Murgas, V. Nascimbeni, F. Pepe, L. Pino, D. Segransan, S. UdryComments: 20 pages, 15 figures, accepted for publication in A&A on 19 December 2019Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)
Ultra-hot Jupiters offer interesting prospects for expanding our theories on dynamical evolution and the properties of extremely irradiated atmospheres. In this context, we present the analysis of new optical spectroscopy for the transiting ultra-hot Jupiter WASP-121b. We first refine the orbital properties of WASP-121b, which is on a nearly polar (obliquity $\psi^{\rm North}$=88.1$\pm$0.25$^{\circ}$ or $\psi^{\rm South}$=91.11$\pm$0.20$^{\circ}$) orbit, and exclude a high differential rotation for its fast-rotating (P$<$1.13 days), highly inclined ($i_\mathrm{\star}^{\rm North}$=8.1$\stackrel{+3.0}{_{-2.6}}^{\circ}$ or $i_\mathrm{\star}^{\rm South}$=171.9$\stackrel{+2.5}{_{-3.4}}^{\circ}$) star. We then present a new method that exploits the reloaded Rossiter-McLaughlin technique to separate the contribution of the planetary atmosphere and of the spectrum of the stellar surface along the transit chord. Its application to HARPS transit spectroscopy of WASP-121b reveals the absorption signature from metals, likely atomic iron, in the planet atmospheric limb. The width of the signal (14.3$\pm$1.2 km/s) can be explained by the rotation of the tidally locked planet. Its blueshift (-5.2$\pm$0.5 km/s) could trace strong winds from the dayside to the nightside, or the anisotropic expansion of the planetary thermosphere.
- [27] arXiv:2001.06844 [pdf, other]
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Title: Measuring line-of-sight sodium density structure using laser guide starsAuthors: Joschua A. Hellemeier, Domenico Bonaccini Calia, Paul Hickson, Angel Otarola, Thomas PfrommerComments: 11 pages, 14 figuresSubjects: Instrumentation and Methods for Astrophysics (astro-ph.IM)
The performance of adaptive optics systems employing sodium laser guide stars can be improved by continuously monitoring the vertical density structure of mesospheric sodium along the line of sight. We demonstrate that sodium density profiles can be retrieved by amplitude modulation of continuous wave (CW) lasers. In an experiment conducted at the Large Zenith Telescope (LZT), ESO's Wendelstein Raman-fibre laser was amplitude-modulated with a pseudo-random binary sequence and profiles were obtained by cross-correlation of the modulation pattern with the observed return signal from the laser guide star. For comparison, high-resolution profiles were obtained simultaneously using the lidar system of the LZT. The profiles obtained by the two techniques show noise contamination, but were found to agree to within the measurement error. As a further check, a comparison was also made between several lidar profiles and those obtained by simultaneous observations using a remote telescope to image the laser plume from the side. The modulated CW lidar technique could be implemented by diverting a small fraction of the returned laser light to a photon counting detector. Theoretical analysis and numerical simulations indicate that, for 50 per cent modulation strength, the sodium centroid altitude could be retrieved every 5 s from a single laser guide star, with an accuracy which would induce a corresponding wavefront error of 50 nm for the ELT and less than 30 nm for the TMT and GMT. If multiple laser guide stars are employed, the required modulation amplitude will be smaller.
- [28] arXiv:2001.06859 [pdf, other]
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Title: A retrograde spin of the black hole in MAXI J1659--152Authors: Sandeep K. Rout (1 and 2), Santosh Vadawale (1), Mariano Méndez (3) ((1) Physical Research Laboratory, Ahmedabad, India, (2) Indian Institute of Technology, Gandhinagar, India and (3) Kapteyn Astronomical Institute, Groningen, The Netherlands)Comments: Published in ApJL. 9 pages, 4 figuresJournal-ref: The Astrophysical Journal Letters, Volume 888, Number 2, 2020 January 10 (L30)Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)
We present the results of spectral analysis of the galactic black-hole binary MAXI J1659--152 in the rising phase of the outburst that lasted for about 65 days starting on 2010 September 25. The presence of a broad Fe line, verified by Monte-Carlo simulations, and coverage of a wide energy band by utilizing the combined spectral capabilities of XMM-Newton/EPIC-pn and RXTE/PCA allowed us to use a combination of reflection spectroscopy and continuum fitting methods to estimate the spin of the black hole. We explored the entire parameter range allowed by the present uncertainties on black-hole mass, inclination, and distance as well as the accretion rate. We show that for about 95 percentage of parameter space and very reasonable upper limits on mass accretion rate, the spin of the black hole has to be negative. This is the first clear detection of negative spin in a galactic black-hole binary.
- [29] arXiv:2001.06873 [pdf, ps, other]
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Title: K-essence scalar dark matter solitons around supermassive black holesComments: 21 pagesSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Phenomenology (hep-ph)
We consider scalar dark matter models where the theory has a shift symmetry only broken by the scalar mass term. We restrict ourselves to K-essence kinetic terms where the shift symmetric part of the Lagrangian is a function of the first derivatives of the scalar field only. In the low-amplitude and nonrelativistic regime, which applies on large galactic scales, scalar clouds form solitons with a finite core. Close to the center of galaxies, where a supermassive Black Hole (BH) resides, we analyze the scalar field distribution and the fate of the dark matter soliton when subject to the BH gravitational attraction. We show that the scalar field profile around such a central BH can be described by new oscillatory solutions of a modified Klein-Gordon equation, which generalize the harmonic oscillations of free scalar dark matter in a flat environment and the Jacobi elliptic functions of the $\phi^4$ model. Moreover, we find that, depending on the form of the K-essence kinetic term, regular solutions can be constructed or not, which connect the relativistic ingoing wavelike profile of the scalar field at the BH horizon to the nearly static nonrelativistic soliton at large distance. These profiles have a constant flux and represent the slow infall of scalar matter into the BH. We show that this regular behavior is only possible for K-essence functions that satisfy the usual conditions for the absence of ghosts and gradient instabilities, together with a new restriction on the growth of the kinetic function $K(X)$ for large argument. It turns out that the same conditions of stability guarantee that quantum corrections are tamed, provided that the mass of the scalar field is less than $10^{-3}$ eV and the strong coupling scale of the model $\Lambda$ is much larger than the scalar mass.
- [30] arXiv:2001.06904 [pdf, other]
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Title: UV & U-band luminosity functions from CLAUDS and HSC-SSP -- I. Using four million galaxies to simultaneously constrain the very faint and bright regimes to $z \sim 3$Authors: Thibaud Moutard, Marcin Sawicki, Stéphane Arnouts, Anneya Golob, Jean Coupon, Olivier Ilbert, Xiaohu Yang, Stephen GwynComments: 18 pages, 11 figures (26 pages, 18 figures including the Appendix). Submitted to MNRAS. Revised versionSubjects: Astrophysics of Galaxies (astro-ph.GA)
We constrain the rest-frame FUV (1546\AA), NUV (2345\AA) and U-band (3690\AA) luminosity functions (LFs) and luminosity densities (LDs) with unprecedented precision from $z \sim 0.2$ up to $z \sim 3$ (FUV, NUV) and $z \sim 2$ (U band). Our sample of more than 4.3 million galaxies, selected from the CFHT Large Area $U$-band Deep Survey (CLAUDS) and HyperSuprime-Cam Subaru Strategic Program (HSC-SSP) data lets us probe the very faint regime (down to $M_\mathrm{FUV}$, $M_\mathrm{NUV}$, $M_\mathrm{U} \simeq -15$) while simultaneously detecting very rare galaxies at the bright end down to comoving densities $<10^{-5}$ Mpc$^{-3}$. Our FUV and NUV LFs are well fitted by a single Schechter function, with faint-end slopes that are very stable up to $z\sim 2$. We confirm, but self-consistently and with much better precision than previous findings that the LDs at all three wavelengths increase rapidly with lookback time to $z\sim1$, and then much more slowly at $1<z<2$-$3$. Evolution of the FUV and NUV LFs and LDs at $z<1$ is driven almost entirely by the fading of the characteristic magnitude, $M^\star_{UV}$, while at $z>1$ it is due to the evolution of both $M^\star_{UV}$ and the characteristic number density $\phi^\star_{UV}$. In contrast, the U-band LF has an excess of faint galaxies and is fitted with a double-Schechter form; $M^\star_\mathrm{U}$ and both $\phi^\star_\mathrm{U}$ components, as well as the bright-end slope evolve throughout $0.2<z<2$, while the faint-end slope appears to be constant over $0.05 < z < 0.6$ (where the double-Schechter profile of the U-band LF is undeniable), at least. We present tables of our Schechter parameters and LD measurements that can be used for testing theoretical galaxy evolution models and forecasting future observations.
- [31] arXiv:2001.06926 [pdf, other]
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Title: Supernova Magnitude Evolution and PAge ApproximationAuthors: Zhiqi HuangComments: 4 pages, 2 figuresSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Phenomenology (hep-ph)
The evidence of environmental dependence of Type Ia supernova luminosity has inspired recent discussion about whether the late-universe cosmic acceleration is still supported by supernova data. We adopt the $\Delta\mathrm{HR}/\Delta\mathrm{age}$ parameter, which describes the dependence of supernova absolute magnitude on the age of supernova progenitor, as an additional nuisance parameter. Using the Pantheon supernova data, a lower bound $\ge 120\,\mathrm{Gyr}$ on the cosmic age, and a Gaussian prior $H_0 = 70\pm 2\,\mathrm{km\,s^{-1}Mpc^{-1}}$ on the Hubble constant, we reconstruct the cosmic acceleration history. Within the flat $\Lambda$ cold dark matter ($\Lambda$CDM) framework, we still find a $5.6\sigma$ detection of cosmic acceleration. This is because a matter dominated decelerating universe would be too young to accommodate observed old stars with age $\gtrsim 120\,\mathrm{Gyr}$. A decelerating but non-flat universe is marginally consistent with the data, however, only in the presence of a negative spatial curvature $\sim$ two orders of magnitude beyond the current constraint from cosmic microwave background data. Finally, we propose a more general Parameterization based on the cosmic Age (PAge), which is {\it not} directly tied to the dark energy concept and hence is ideal for a null test of the cosmic acceleration. We find that, for a magnitude evolution rate $\Delta\mathrm{HR}/\Delta\mathrm{age} \lesssim 0.3\,\mathrm{mag}/5.3\,\mathrm{Gyr}$ \cite{Kang19}, a spatially flat and decelerating PAge universe is fully consistent with the supernova data and the cosmic age bound, and has no tension with the geometric constraint from the observed CMB acoustic angular scales.
- [32] arXiv:2001.06929 [pdf, ps, other]
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Title: Extreme Ultraviolet Late Phase of Solar FlaresComments: accepted for publication in AAS journalsSubjects: Solar and Stellar Astrophysics (astro-ph.SR)
A second peak in extreme ultraviolet sometimes appears during the gradual phase of solar flares, which is known as EUV late phase (ELP). Stereotypically ELP is associated with two separated sets of flaring loops with distinct sizes, and it has been debated whether ELP is caused by additional heating or extended plasma cooling in the longer loop system. Here we carry out a survey of 55 M-and-above GOES-class flares with ELP during 2010--2014. Based on the flare-ribbon morphology, these flares are categorized as circular-ribbon (19 events), two-ribbon (23 events), and complex-ribbon (13 events) flares. Among them, 22 events (40%) are associated with coronal mass ejections, while the rest are confined. An extreme ELP, with the late-phase peak exceeding the main-phase peak, is found in 48% of two-ribbon flares, 37% of circular-ribbon flares, and 31% of complex-ribbon flares, suggesting that additional heating is more likely present during ELP in two-ribbon than in circular-ribbon flares. Overall, cooling may be the dominant factor causing the delay of the ELP peak relative to the main-phase peak, because the loop system responsible for the ELP emission is generally larger than, and well separated from, that responsible for the main-phase emission. All but one of the circular-ribbon flares can be well explained by a composite "dome-plate" quasi-separatrix layer (QSL). Only half of these show a magnetic null point, with its fan and spine embedded in the dome and plate, respectively. The dome-plate QSL, therefore, is a general and robust structure characterizing circular-ribbon flares.
- [33] arXiv:2001.06969 [pdf, ps, other]
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Title: Effect of feedback of massive stars in the fragmentation, distribution, and kinematics of the gas in two star forming regions in the Carina NebulaAuthors: David Rebolledo, Andrés E. Guzmán, Yanett Contreras, Guido Garay, S.-N. X. Medina, Patricio Sanhueza, Anne J. Green, Camila Castro, Viviana Guzmán, Michael G. BurtonComments: Accepted for publication in the Astrophysical Journal the 20th of January 2020Subjects: Astrophysics of Galaxies (astro-ph.GA)
We present ALMA high spatial resolution observations towards two star forming regions located in one of the most extreme zones of star formation in the Galaxy, the Carina Nebula. One region is located at the center of the nebula and is severally affected by the stellar feedback from high-mass stars, while the other region is located further south and is less disturbed by the massive star clusters. We found that the region at the center of the nebula is forming less but more massive cores than the region located in the south, suggesting that the level of stellar feedback effectively influence the fragmentation process in clumps. Lines such as HCN, HCO$^{+}$ and SiO show abundant and complex gas distributions in both regions, confirming the presence of ionization and shock fronts. Jeans analysis suggests that the observed core masses in the region less affected by the massive stars are consistent with thermal fragmentation, but turbulent Jeans fragmentation might explain the high masses of the cores identified in the region in the center of Carina. Consistently, two different analyses in the HCO$^{+}$ line provided evidence for a higher level of turbulence in the gas more affected by the stellar feedback. The gas column density probability functions, N-PDFs, show log-normal shapes with clear transitions to power law regimes. We observed a wider N-PDF in the region at the center of the nebula, which provides further evidence for a higher level of turbulence in the material with a higher level of massive stellar feedback.
- [34] arXiv:2001.06978 [pdf, ps, other]
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Title: An Atmospheric Cerenkov Telescope Simulation SystemAuthors: Srikanta SinhaComments: 8 pages, 5 figuresSubjects: Instrumentation and Methods for Astrophysics (astro-ph.IM)
A detailed numerical procedure has been developed to simulate the mechanical configurations and optical properties of Imaging Atmospheric Cerenkov Telescope systems. To test these procedures a few existing ACT arrays are simulated. First results from these simulations are presented.
- [35] arXiv:2001.06982 [pdf, ps, other]
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Title: Chemistry and physics of a low-metallicity hot core in the Large Magellanic CloudAuthors: Takashi Shimonishi, Ankan Das, Nami Sakai, Kei E. I. Tanaka, Yuri Aikawa, Takashi Onaka, Yoshimasa Watanabe, Yuri NishimuraComments: Accepted for publication in ApJ, 30 pages, 14 figures, 10 tablesSubjects: Astrophysics of Galaxies (astro-ph.GA); Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)
We present the results of 0.1-pc-scale observations in 250 GHz and 350GHz towards a newly-discovered hot molecular core in a nearby low-metallicity galaxy, the Large Magellanic Cloud (LMC), with the Atacama Large Millimeter/submillimeter Array. A variety of C/N/O/Si/S-bearing molecules are detected towards the high-mass young stellar object, ST16. A rotating protostellar envelope is for the first time detected outside our Galaxy by SO2 and 34SO lines. An outflow cavity is traced by CCH and CN. The isotope abundance of sulfur in the source is estimated to be 32S/34S = 17 and 32S/33S = 53 based on SO, SO2, and CS isotopologues, suggesting that both 34S and 33S are overabundant in the LMC. Rotation diagram analyses show that the source is associated with hot gas (>100K) traced by high-excitation lines of CH3OH and SO2, as well as warm gas (~50K) traced by CH3OH, SO2, 34SO, OCS, CH3CN lines. A comparison of molecular abundances between LMC and Galactic hot cores suggests that organic molecules (e.g., CH3OH, a classical hot core tracer) show a large abundance variation in low metallicity, where the present source is classified into an organic-poor hot core. Our astrochemical simulations suggest that different grain temperature during the initial ice-forming stage would contribute to the chemical differentiation. In contrast, SO2 shows similar abundances within all the known LMC hot cores and the typical abundance roughly scales with the LMC's metallicity. Nitrogen-bearing molecules are generally less abundant in LMC hot cores, except for NO. The present results suggest that chemical compositions of hot cores do not always simply scale with the metallicity.
- [36] arXiv:2001.06986 [pdf, other]
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Title: Meso-scale Instability Triggered by Dust Feedback in Dusty Rings: Origin and Observational ImplicationsComments: 22 pages, 16 figures, Submitted to ApJSubjects: Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)
High spatial resolution observations of protoplanetary disks (PPDs) by ALMA have revealed many details that are providing interesting constraints on the disk physics as well as dust dynamics, both of which are essential for understanding planet formation. We carry out high-resolution, 2D global hydrodynamic simulations, including the effects of dust feedback, to study the stability of dusty rings. When the ring edges are relatively sharp and the dust surface density becomes comparable to the gas surface density, we find that dust feedback enhances the radial gradients of both the azimuthal velocity profile and the potential vorticity profile at the ring edges. This eventually leads to instabilities on meso-scales (spatial scales of several disk scale heights), causing dusty rings to be populated with many compact regions with highly concentrated dust densities on meso-scales. We also produce synthetic dust emission images using our simulation results and discuss the comparison between simulations and observations.
- [37] arXiv:2001.06997 [pdf, other]
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Title: The redshift and star formation mode of AzTEC2: a pair of massive galaxies at $z=4.63$Authors: E. F. Jiménez-Andrade, J. A. Zavala, B. Magnelli, C. M. Casey, D. Liu, E. Romano-Díaz, E. Schinnerer, K. Harrington, I. Aretxaga, A. Karim, J. Staguhn, A. D. Burnham, A. Montaña, V. Smolčić, M. Yun, F. Bertoldi, D. HughesComments: 19 pages, 6 figures, accepted for publication in ApJSubjects: Astrophysics of Galaxies (astro-ph.GA)
We combine observations from the Atacama Large Millimeter/submillimeter Array (ALMA) and the NOrthern Extended Millimeter Array (NOEMA) to assess the redshift and to study the star formation conditions in AzTEC2: one of the brightest sub-millimeter galaxies (SMGs) in the COSMOS field ($S_{\rm 1.1mm}=10.5\pm1.4$mJy). Our high-resolution observations confirm that AzTEC2 splits into two components (namely AzTEC2-A and AzTEC2-B) for which we detect [C$\,$II] and $^{12}$CO(5$\to$4) line emission, implying a redshift of $4.626\pm0.001$ ($4.633\pm0.001$) for AzTEC2-A (AzTEC2-B) and ruling out previous associations with a galaxy at $z\sim1$. We use the $^{12}$CO(5$\to$4) line emission and adopt typical SMG-like gas excitation conditions to estimate the molecular gas mass, which is $M_{\rm gas}(\alpha_{\rm CO}/2.5)=2.1\pm0.4 \times10^{11}{\rm M}_\odot$ for AzTEC2-A, and a factor four lower for AzTEC2-B. With the infrared-derived star formation rate of AzTEC2-A ($1920\pm100 \,M_\odot{\rm \, yr}^{-1}$) and AzTEC2-B ($710\pm 35\,M_\odot{\rm \,yr}^{-1}$), they both will consume their current gas reservoir within $(30-200)\,$Myr. We find evidence of a rotation-dominated [C$\,$II] disk in AzTEC2-A, with a de-projected rotational velocity of $v_{\rm rot}(i=39^\circ)=660\pm130{\rm \,km\,s}^{-1}$, velocity dispersion $\lesssim100{\rm \,km\,s}^{-1}$, and dynamical mass of $M_{\rm dyn}(i=39^\circ)=2.6^{+1.2}_{-0.9}\times10^{11}\,M_\odot$. We propose that an elevated gas accretion rate from the cosmic web might be the main driver of the intense levels of star formation in AzTEC2-A, which might be further enhanced by gravitational torques induced by its minor companion (AzTEC2-B). These results strengthen the picture whereby the population of single-dish selected SMGs is rather heterogeneous, including a population of pairs of massive, highly-active galaxies in a pre-coalescence phase.
- [38] arXiv:2001.07012 [pdf, other]
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Title: Gauss-Bonnet Inflation after Planck2018Comments: 52 pages, 16 figures, 16 tables, Accepted for publication in The Astrophysical JournalSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Phenomenology (hep-ph)
We study the primordial perturbations and reheating process in the models where the Gauss-Bonnet term is non-minimally coupled to the canonical and non-canonical (DBI and tachyon) scalar fields. We consider several potentials and Gauss-Bonnet coupling terms as power-law, dilaton-like, $\cosh$-type, E-model and T-model. To seek the observational viability of these models, we study the scalar perturbations numerically and compare the results with the Planck2018 TT, TE, EE+lowE+lensing+BK14+BAO joint data at $68\%$ CL and $95\%$ CL. We also study the tensor perturbations in confrontation with the Planck2018 TT, TE, EE+lowE+lensing+BK14+BAO+ LIGO$\&$Virgo2016 joint data at $68\%$ CL and $95\%$ CL. In this regard, we obtain some constraints on the Gauss-Bonnet coupling parameter $\beta$. Another important process in the early universe is the reheating phase after inflation which is necessary to reheat the universe for subsequent evolution. In this regard, we study the reheating process in these models and find some expressions for the e-folds number and temperature during that era. Considering that from Planck TT,TE,EE+lowEB+lensing data and BICEP2/Keck Array 2014, based on the $\Lambda$CDM$+r+\frac{dn_{s}}{d\ln k}$ model, we have $n_{s}=0.9658\pm 0.0038$ and $r<0.072$, we obtain some constraints on the e-folds number and temperature. From the values of the e-folds number and the effective equation of state and also the observationally viable value of the scalar spectral index, we explore the capability of the models in explaining the reheating phase.
- [39] arXiv:2001.07014 [pdf, other]
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Title: eXTP perspectives for the $ν$MSM sterile neutrino dark matter modelSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); Instrumentation and Methods for Astrophysics (astro-ph.IM)
We discuss the potential of the eXTP X-ray telescope, in particular its Soft Focusing Array (SFA) and Large Area Detector (LAD), for the detection of a signal from keV-scale decaying dark matter. We show that the sensitivity of the eXTP is sufficient to improve existing constraints on the mixing angle of the neutrino Minimal extension of the Standard Model ($\nu$MSM) by a factor of 5 within the dark matter mass range 2-50 keV, assuming a zero level of systematic uncertainty. At the same time the minimal level of systematic uncertainty (~0.5%) can significantly impair obtained constraints for $m_{DM}>20$ keV. We argue that even in this case the eXTP will be able to probe previously inaccessible range of $\nu$MSM parameters and serve as a precursor for the Athena mission in decaying dark matter searches.
- [40] arXiv:2001.07021 [pdf, ps, other]
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Title: The viable f(G) gravity models via reconstruction from the observationsComments: 17 pages, 9 figuresSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc)
We reconstruct the viable f(G) gravity models from the observations and provide the analytic solutions that well describe our numerical results. In order to avoid unphysical challenges that occur during the numerical reconstruction, we generalize f(G) models into f(GA), which is the simple extension of f(G) models with the introduction of a constant A parameter. We employ several observational data together with the stability condition, which reads d2f/dG2 > 0 and must be satisfied in the late-time evolution of the universe, to give proper initial conditions for solving the perturbation equation. As a result, we obtain the analytic functions that match the numerical solutions. Furthermore, it might be interesting if one can find the physical origin of those analytic solutions and its cosmological implications.
- [41] arXiv:2001.07030 [pdf, ps, other]
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Title: Physical parameters of selected Gaia mass asteroidsAuthors: E. Podlewska-Gaca, A. Marciniak, V. Alí-Lagoa, P. Bartczak, T. G. Müller, R. Szakáts, R. Duffard, L. Molnár, A. Pál, M. Butkiewicz-Bąk, G. Dudziński, K. Dziadura, P. Antonini, V. Asenjo, M. Audejean, Z. Benkhaldoun, R. Behrend, L. Bernasconi, J. M. Bosch, A. Chapman, B. Dintinjana, A. Farkas, M. Ferrais, S. Geier, J. Grice, R. Hirsh, H. Jacquinot, E. Jehin, A. Jones, D. Molina, N. Morales, N. Parley, R. Poncy, R.Roy, T. Santana-Ros, B. Seli, K. Sobkowiak, E. Verebélyi, K. ŻukowskiComments: Accepted for publication in A&ASubjects: Earth and Planetary Astrophysics (astro-ph.EP)
Thanks to the Gaia mission, it will be possible to determine the masses of approximately hundreds of large main belt asteroids with very good precision. We currently have diameter estimates for all of them that can be used to compute their volume and hence their density. However, some of those diameters are still based on simple thermal models, which can occasionally lead to volume uncertainties as high as 20-30%. The aim of this paper is to determine the 3D shape models and compute the volumes for 13 main belt asteroids that were selected from those targets for which Gaia will provide the mass with an accuracy of better than 10%. We used the genetic Shaping Asteroids with Genetic Evolution (SAGE) algorithm to fit disk-integrated, dense photometric lightcurves and obtain detailed asteroid shape models. These models were scaled by fitting them to available stellar occultation and/or thermal infrared observations. We determine the spin and shape models for 13 main belt asteroids using the SAGE algorithm. Occultation fitting enables us to confirm main shape features and the spin state, while thermophysical modeling leads to more precise diameters as well as estimates of thermal inertia values. We calculated the volume of our sample of main-belt asteroids for which the Gaia satellite will provide precise mass determinations. From our volumes, it will then be possible to more accurately compute the bulk density, which is a fundamental physical property needed to understand the formation and evolution processes of small solar system bodies.
- [42] arXiv:2001.07036 [pdf, other]
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Title: Formation of plasmoid chains and fast magnetic reconnection during nonlinear evolution of the tilt instabilityAuthors: Hubert BatyComments: Oral contribution from the 17th European Fusion Theory ConferenceSubjects: Solar and Stellar Astrophysics (astro-ph.SR); Plasma Physics (physics.plasm-ph); Space Physics (physics.space-ph)
We investigate, by means of two-dimensional incompressible magnetohydrodynamic (MHD) numerical simulations, the fast collisional magnetic reconnection regime that is supported by the formation of plasmoid chains when the Lundquist number $S$ exceeds a critical value. A recently developed characteristic-Galerkin finite-element code, FINMHD, that is specifically designed for this aim in a reduced visco-resistive MHD framework, is employed. Contrary to previous studies, a different initial setup of two repelling current channels is chosen in order to form two quasi-singular current layers on an Alfv\'enic time scale as a consequence of the tilt instability. If $S < 5 \times 10^3$, a subsequent stationary reconnection process is obtained with a rate scaling as $S^{-1/2}$ as predicted by the classical Sweet-Parker model. Otherwise, a stochastic time-dependent reconnection regime occurs, with a fast time-averaged rate independent of $S$ and having a normalized value of $0.014$. The latter regime is triggered by the formation of two chains of plasmoids disrupting the current sheets with a sudden super-Alfv\'enic growth following a quiescent phase, in agreement with the general theory of the plasmoid instability proposed by Comisso et al. [Phys. Plasmas 23, 100702 (2016)]. Moreover, the non-monotonic dependence of the plasmoid growth rate with $S$ following an asymptotically decreasing logarithmic law in the infinite $S$-limit is confirmed. We also closely compare our results to those obtained during the development of the coalescence instability setup in order to assess the generality of the mechanism. Finally, we briefly discuss the relevance of our results to explain the flaring activity in solar corona and internal disruptions in tokamaks.
- [43] arXiv:2001.07041 [pdf, ps, other]
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Title: The effect of warm gas on the buckling instability in galactic barsAuthors: Ewa L. LokasComments: 11 pages, 12 figures, accepted for publication in A&ASubjects: Astrophysics of Galaxies (astro-ph.GA)
By using $N$-body and hydro simulations, we study the formation and evolution of bars in galaxies with significant gas content focusing on the phenomenon of the buckling instability. The galaxies are initially composed of a spherical dark matter halo and only stellar, or stellar and gaseous, disks with parameters that are similar to the Milky Way and are evolved for 10 Gyr. We consider different values of the gas fraction $f =0-0.3$ and in order to isolate the effect of the gas, we kept the fraction constant during the evolution by not allowing the gas to cool and form stars. The stellar bars that form in simulations with higher gas fractions are weaker and shorter, and they do not form at all for gas fractions that are higher than 0.3. The bar with a gas fraction of 0.1 forms sooner due to initial perturbations in the gas, but despite the longer evolution, it does not become stronger than the one in the collisionless case at the end of evolution. The bars in the gas component are weaker; they reach their maximum strength around 4 Gyr and later decline to transform into spheroidal shapes. The distortion of the stellar bar during the buckling instability is weaker for higher gas fractions and weakens the bar less significantly, but it has a similar structure both in terms of radial profiles and in face-on projections. For $f=0.2,$ the first buckling lasts significantly longer and the bar does not undergo the secondary buckling event, while for $f=0.3,$ the buckling does not occur. Despite these differences, all bars develop boxy/peanut shapes in the stellar and gas component by the end of the evolution, although their thickness is smaller for higher gas fractions.
- [44] arXiv:2001.07048 [pdf]
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Title: On the variation of solar coronal rotation using SDO/AIA observationsComments: 9 pages, 5 figures, and 2 tables; MNRASSubjects: Solar and Stellar Astrophysics (astro-ph.SR)
We report on the variability of rotation periods of solar coronal layers with respect to temperature (or, height). For this purpose, we have used the observations from Atmospheric Imaging Assembly (AIA) telescope on board Solar Dynamics Observatory (SDO) space mission. The images used are at the wavelengths 94 {\AA}, 131 {\AA}, 171 {\AA}, 193 {\AA}, 211 {\AA}, and 335 {\AA} for the period from 2012 to 2018. Analysis of solar full disk images obtained at these wavelengths by AIA is carried out using flux modulation method. Seventeen rectangular strips/bins at equal interval of 10 degrees (extending from 80 degree South to 80 degree North on the Sun) are selected to extract a time series of extreme ultraviolet (EUV) intensity variations to obtain auto-correlation coefficient. The peak of Gaussian fit to first secondary maxima in the autocorrelogram gives synodic rotation period. Our analysis shows the differential rotation with respect to latitude as well as temperature (or, height). In the present study, we find that the sidereal rotation periods of different coronal layers decrease with increasing temperature (or, height). Average sidereal rotation period at the lowest temperature (~ 600000 Kelvin) corresponding to AIA-171 {\AA} which originates from the upper transition region/quiet corona is 27.03 days. The sidereal rotation period decreases with temperature (or, height) to 25.47 days at the higher temperature (~10 million Kelvin) corresponding to the flaring regions of solar corona as seen in AIA-131 {\AA} observations.
- [45] arXiv:2001.07065 [pdf, ps, other]
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Title: Update of the Solar Lyman-Alpha Profile Line ModelComments: 9 pages, 7 figures, 2 tables Submitted to ApJSubjects: Solar and Stellar Astrophysics (astro-ph.SR)
We present a modification of a model of solar cycle evolution of the solar Lyman-alpha line profile, along with a sensitivity study of interstellar neutral H hydrogen to uncertainties in radiation pressure level. The line profile model, originally developed by Kowalska-Leszczynska et al. 2018a, is parametrized by the composite solar Lyman-alpha flux, which recently was revised Machol et al. 2019. We present modified parameters of the previously-developed model of solar radiation pressure for neutral hydrogen and deuterium atoms in the heliosphere. The mathematical function used in the model, as well as the fitting procedure, remain unchanged. We show selected effects of the model modification on ISN H properties in the heliosphere and we discuss the sensitivity of these quantities to uncertainties in the calibration of the composite Lyman-alpha series.
- [46] arXiv:2001.07078 [pdf, other]
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Title: Tracking downflows from the chromosphere to the photosphere in a solar arch filament systemAuthors: S. J. González Manrique (1), C. Kuckein (2), A. Pastor Yabar (3), A. Diercke (2,4), M. Collados (5), P. Gömöry (1), S. Zhong (6,7), Y. Hou (6,7), C. Denker (2) ((1) Astronomical Institute, Slovak Academy of Sciences, (2) Leibniz-Institut für Astrophysik Potsdam, (3) Leibniz-Institut für Sonnenphysik, Freiburg, (4) Universität Potsdam, Institut für Physik und Astronomie, (5) Instituto de Astrofísica de Canarias, (6) CAS Key Laboratory of Solar Activity, National Astronomical Observatories, Chinese Academy of Sciences, (7) University of Chinese Academy of Sciences, Beijing)Comments: Accepted for publication in The Astrophysical Journal, 9 pages, 4 figuresSubjects: Solar and Stellar Astrophysics (astro-ph.SR)
We study the dynamics of plasma along the legs of an arch filament system (AFS) from the chromosphere to the photosphere, observed with high-cadence spectroscopic data from two ground-based solar telescopes: the GREGOR telescope (Tenerife) using the GREGOR Infrarred Spectrograph (GRIS) in the He I 10830 \r{A} range and the Swedish Solar Telescope (La Palma) using the CRisp Imaging Spectro-Polarimeter to observe the Ca II 8542 \r{A} and Fe I 6173 \r{A} spectral lines. The temporal evolution of the draining of the plasma was followed along the legs of a single arch filament from the chromosphere to the photosphere. The average Doppler velocities inferred at the upper chromosphere from the He I 10830 \r{A} triplet reach velocities up to 20-24~km~s$^{-1}$, in the lower chromosphere and upper photosphere the Doppler velocities reach up to 11~km~s$^{-1}$ and 1.5~km~s$^{-1}$ in the case of the Ca II 8542 \r{A} and Si I 10827 \r{A} spectral lines, respectively. The evolution of the Doppler velocities at different layers of the solar atmosphere (chromosphere and upper photosphere) shows that they follow the same LOS velocity pattern, which confirm the observational evidence that the plasma drains towards the photosphere as proposed in models of AFSs. The Doppler velocity maps inferred from the lower photospheric Ca I 10839 \r{A} or Fe I 6173 \r{A} spectral lines do not show the same LOS velocity pattern. Thus, there is no evidence that the plasma reaches the lower photosphere. The observations and the nonlinear force-free field extrapolations demonstrate that the magnetic field loops of the AFS rise with time. We found flow asymmetries at different footpoints of the AFS. The NLFFF values of the magnetic field strength give us a clue to explain these flow asymmetries.
- [47] arXiv:2001.07111 [pdf, ps, other]
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Title: Type Ic Supernova of a 22 $\text{M}_{\odot}$ ProgenitorAuthors: Jacob Teffs (1), Thomas Ertl (1), Paolo Mazzali (1, 2), Stephan Hachinger (3), Thomas Janka (2) ((1) ARI Liverpool John Moores University (2) Max-Planck Institut für Astrophysik, (3) Leibniz Supercomputing Centre)Comments: 17 pages,18 figures. to be published in MNRASSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR)
Type Ic supernovae (SNe Ic) are a sub-class of core-collapse supernovae that exhibit no helium or hydrogen lines in their spectra. Their progenitors are thought to be bare carbon-oxygen cores formed during the evolution of massive stars that are stripped of their hydrogen and helium envelopes sometime before collapse. SNe Ic present a range of luminosities and spectral properties, from luminous GRB-SNe with broad-lined spectra to less luminous events with narrow-line spectra. Modelling SNe\,Ic reveals a wide range of both kinetic energies, ejecta masses, and $^{56}\text{Ni}$ masses. To explore this diversity and how it comes about, light curves and spectra are computed from the ejecta following the explosion of an initially 22 $\text{M}_{\odot}$ progenitor that was artificially stripped of its hydrogen and helium shells, producing a bare CO core of $\sim$ 5 $\text{M}_{\odot}$, resulting in an ejected mass of $\sim$ 4 $\text{M}_{\odot}$, which is an average value for SNe Ic. Four different explosion energies are used that cover a range of observed SNe. Finally, $^{56}\text{Ni}$ and other elements are artificially mixed in the ejecta using two approximations to determine how element distribution affects light curves and spectra. The combination of different explosion energy and degree of mixing produces spectra that roughly replicate the distribution of near-peak spectroscopic features of SNe Ic. High explosion energies combined with extensive mixing can produce red, broad-lined spectra, while minimal mixing and a lower explosion energy produce bluer, narrow-lined spectra.
- [48] arXiv:2001.07122 [pdf, other]
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Title: Hunting for open clusters in \textit{Gaia} DR2: $582$ new OCs in the Galactic discAuthors: A. Castro-Ginard (1), C. Jordi (1), X. Luri (1), J. Álvarez Cid-Fuentes (2), L. Casamiquela (3), F. Anders (1), T. Cantat-Gaudin (1), M. Monguió (1), L. Balaguer-Núñez (1), S. Solà (2), R.M. Badia (2) ((1) Dept. Física Quàntica i Astrofísica, Institut de Ciències del Cosmos (ICCUB), Universitat de Barcelona (IEEC-UB), Martí i Franquès 1, E08028 Barcelona, Spain, (2) Barcelona Supercomputing Center (BSC), (3) Laboratoire d'Astrophysique de Bordeaux, Univ. Bordeaux, CNRS, B18N, allée Geoffroy Saint-Hilaire, 33615 Pessac, France)Comments: 11 pages, 9 figures, accepted for publication by Astronomy and Astrophysics (A&A) the 18th January, 2020. Tables 1 and 2 available at the CDSSubjects: Astrophysics of Galaxies (astro-ph.GA); Solar and Stellar Astrophysics (astro-ph.SR)
Open clusters are key targets for both Galaxy structure and evolution and stellar physics studies. Since \textit{Gaia} DR2 publication, the discovery of undetected clusters has proven that our samples were not complete. Our aim is to exploit the Big Data capabilities of machine learning to detect new open clusters in \textit{Gaia} DR2, and to complete the open cluster sample to enable further studies on the Galactic disc. We use a machine learning based methodology to systematically search in the Galactic disc, looking for overdensities in the astrometric space and identifying them as open clusters using photometric information. First, we use an unsupervised clustering algorithm, DBSCAN, to blindly search for these overdensities in \textit{Gaia} DR2 $(l,b,\varpi,\mu_{\alpha^*},\mu_\delta)$. After that, we use a deep learning artificial neural network trained on colour-magnitude diagrams to identify isochrone patterns in these overdensities, and to confirm them as open clusters. We find $582$ new open clusters distributed along the Galactic disc, in the region $|b| < 20$. We can detect substructure in complex regions, and identify the tidal tails of a disrupting cluster UBC~$274$ of $\sim 3$ Gyr located at $\sim 2$ kpc. Adapting the methodology into a Big Data environment allows us to target the search driven by physical properties of the open clusters, instead of being driven by its computational requirements. This blind search for open clusters in the Galactic disc increases in a $45\%$ the number of known open clusters.
- [49] arXiv:2001.07123 [pdf]
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Title: Thermal evolution of the early MoonComments: Accepted in Meteoritics & Planetary Science, 39 pages, 5 figuresJournal-ref: Meteorit Planet Sci, 53: 2193-2211 (2018)Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
The early thermal evolution of Moon has been numerically simulated to understand the magnitude of the impact induced heating and the initially stored thermal energy of the accreting Moonlets. The main objective of the present study is to understand the nature of processes leading to core-mantle differentiation and the production and cooling of the initial convective magma ocean. The accretion of Moon was commenced over a timescale of 100 years after the giant impact event around 30-100 million years in the early solar system. We studied the dependence of the planetary processes on the impact scenarios, the initial average temperature of the accreting moonlets and the size of the protoMoon that accreted rapidly beyond the Roche limit within the initial one year after the giant impact. The simulations indicate that the accreting Moonlets should have a minimum initial averaged temperature around 1600 K. The impacts would provide additional thermal energy. The initial thermal state of the moonlets depends upon the environment prevailing within the Roche limit that experienced episodes of extensive vaporization and re-condensation of silicates. The initial convective magma ocean of depth more than 1000 km is produced in the majority of simulations along with the global core-mantle differentiation in case the melt percolation of the molten metal through porous flow from bulk silicates was not the major mode of core-mantle differentiation. The possibility of shallow magma oceans cannot be ruled out in the presence of the porous flow. Our simulations indicate the core-mantle differentiation within the initial $10^2$-$10^3$ years of the Moon accretion. The majority of the convective magma ocean cooled down for crystallization within the initial $10^3$-$10^4$ years.
- [50] arXiv:2001.07126 [pdf, ps, other]
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Title: Chemical abundances of Seyfert 2 AGNs $-$II. N2 metallicity calibration based on SDSSAuthors: S. P. Carvalho, O. L. Dors, M. V. Cardaci, G. F. Hagele, A. C. Krabbe, E. Perez-Montero, A. F. Monteiro, M. Armah, P. Freitas-LemesComments: 10 pages, 6 figuras, accepted for publication in MNRASSubjects: Astrophysics of Galaxies (astro-ph.GA)
We present a semi-empirical calibration between the metallicity ($Z$) of Seyfert 2 Active Galactic Nuclei and the $N2$=log([N II]$\lambda$6584/H$\alpha$) emission-line intensity ratio. This calibration was derived through the [O III]$\lambda$5007/[O II]$\lambda$3727 versus $N2$ diagram containing observational data and photoionization model results obtained with the Cloudy code. The observational sample consists of 463 confirmed Seyfert 2 nuclei (redshift $z < 0.4$) taken from the Sloan Digital Sky Survey DR7 dataset. The obtained $Z$-$N2$ relation is valid for the range $0.3 < (Z/Z_{\odot}) < 2.0$ which corresponds to $-0.7 < \: (N2) < 0.6$. The effects of varying the ionization parameter ($U$), electron density and the slope of the spectral energy distribution on the $Z$ estimations are of the order of the uncertainty produced by the error measurements of $N2$. This result indicates the large reliability of our $Z-N2$ calibration. A relation between $U$ and the [O III]/[O II] line ratio, almost independent of other nebular parameter, was obtained.
- [51] arXiv:2001.07129 [pdf, ps, other]
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Title: Gravity and limb-darkening coefficients for compact stars: DA, DB, and DBA eclipsing white dwarfsComments: Accepted for publication in Astronomy&AstrophysicsSubjects: Solar and Stellar Astrophysics (astro-ph.SR)
The main objective of the present work is to extend these investigations by computing the gravity and limb-darkening coefficients for white dwarf atmosphere models with hydrogen, helium, or mixed compositions (types DA, DB, and DBA).
We computed gravity and limb-darkening coefficients for DA, DB, and DBA white dwarfs atmosphere models, covering the transmission curves of the Sloan, UBVRI, Kepler, TESS, and Gaia photometric systems. Specific calculations for the HiPERCAM instrument were also carried out. For all calculations of the limb-darkening coefficients we used the least-squares method. Concerning the effects of tidal and rotational distortions, we also computed for the first time the gravity-darkening coefficients $y(\lambda)$ for white dwarfs using the same models of stellar atmospheres as in the case of limb-darkening. A more general differential equation was introduced to derive these quantities, including the partial derivative $\left(\partial{\ln I_o(\lambda)}/{\partial{\ln g}}\right)_{T_{\rm eff}}$.
Six laws were adopted to describe the specific intensity distribution: linear, quadratic, square root, logarithmic, power-2, and a more general one with four coefficients. The computations are presented for the chemical compositions log[H/He] = $-$10.0 (DB), $-$2.0 (DBA) and He/H = 0 (DA), with log g varying between 5.0 and 9.5 and effective temperatures between 3750 K-100\,000 K. For effective temperatures higher than 40\,000 K, the models were also computed adopting nonlocal thermal equilibirum (DA). The adopted mixing-length parameters are ML2/$\alpha = 0.8$ (DA case) and 1.25 (DB and DBA). The results are presented in the form of 112 tables. Additional calculations, such as for other photometric systems and/or different values of log[H/He], $\log g,$ and T$_{\rm eff}$ can be performed upon request. - [52] arXiv:2001.07138 [pdf, ps, other]
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Title: A multi-wavelength study of the gamma-ray binary candidate HESS J1832-093Authors: Pak-Hin Thomas Tam (1), K. K. Lee (2), Yudong Cui (1), A. K. H. Kong (3), K. L. Li (4), Vlad Tudor (5), Xinbo He (1), C. P. Hu (6), Partha S. Pal (1) ((1) Sun Yat-sen University, (2) Chinese University of Hong Kong, (3) National Tsing Hua University, (4) UNIST, (5) Curtin U., (6) Kyoto U.)Comments: 9 pages, 5 figures, submittedSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
We investigate the nature of the unidentified very-high-energy (VHE) gamma-ray object, HESS J1832-093, in a multi-wavelength context. Based on X-ray variability and spectral index ($\Gamma_X\sim\,1.5$), and its broad-band spectrum (which was remarkably similar to HESS J0632+057, a confirmed gamma-ray binary), HESS J1832-093 has been considered to be a strong gamma-ray binary candidate in previous works. In this work, we provide further evidence for this scenario. We obtained a spectrum of its IR counterpart using Gemini/Flamingo, finding absorption lines that are usually seen in massive stars, in particular O stars. We also obtained a rather steep ATCA spectrum ($\alpha=-1.18^{+1.04}_{-0.88}$) which prefers a gamma-ray binary over an AGN scenario. Based on spatial-spectral analysis and variability search, we found that 4FGL J1832.9-0913 is possible to be associated with SNR G22.7-0.2 rather than with HESS J1832-093 only.
- [53] arXiv:2001.07159 [pdf, other]
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Title: First Detection of Spectral Variations of Anomalous Microwave Emission with QUIJOTE and C-BASSAuthors: R. Cepeda-Arroita (1), S. Harper (1), C. Dickinson (1, 2), J. A. Rubiño-Martín (3, 4), R. T. Génova-Santos (3, 4), Angela C. Taylor (5), T. J. Pearson (2), M. Ashdown (6, 7), A. Barr (1), R. B. Barreiro (8), B. Casaponsa (8), F. J. Casas (8), H. C. Chiang (9, 10), R. Fernandez-Cobos (8), R. D. P. Grumitt (5), F. Guidi (3, 4), H. M. Heilgendorff (10), D. Herranz (8), L. R. P. Jew (5), J. L. Jonas (11, 12), Michael E. Jones (5), A. Lasenby (6, 7), J. Leech (5), J. P. Leahy (1), E. Martínez-González (8), M. W. Peel (1, 3, 4), F. Poidevin (3, 4), L. Piccirillo (1), A. C. S. Readhead (2), R. Rebolo (3, 4, 13), B. Ruiz-Granados (3, 4, 14, 15), J. Sievers (9, 16), F. Vansyngel (3, 4), P. Vielva (8), R. A. Watson (1) ((1) University of Manchester, (2) California Institute of Technology, (3) Instituto de Astrofísica de Canarias, (4) Universidad de La Laguna, (5) University of Oxford, (6) Cavendish Laboratory, University of Cambridge, (7) Kavli Institute for Cosmology, University of Cambridge, (8) CSIC-Universidad de Cantabria, (9) McGill University (10) School of Mathematics, Statistics & Computer Science, University of KwaZulu-Natal (11) Rhodes University (12) South African Radio Astronomy Observatory (13) Consejo Superior de Investigaciones Científicas (14) Agenzia Spaziale Italiana (15) Istituto Nazionale di Fisica Nucleare (16) School of Chemistry & Physics, University of KwaZulu-Natal)Comments: 18 pages, 7 figures, submitted to MNRASSubjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
Anomalous Microwave Emission (AME) is a significant component of Galactic diffuse emission in the frequency range $10$-$60\,$GHz and a new window into the properties of sub-nanometre-sized grains in the interstellar medium. We investigate the morphology of AME in the $\approx10^{\circ}$ diameter $\lambda$ Orionis ring by combining intensity data from the QUIJOTE experiment at $11$, $13$, $17$ and $19\,$GHz and the C-Band All Sky Survey (C-BASS) at $4.76\,$GHz, together with 19 ancillary datasets between $1.42$ and $3000\,$GHz. Maps of physical parameters at $1^{\circ}$ resolution are produced through Markov Chain Monte Carlo (MCMC) fits of spectral energy distributions (SEDs), approximating the AME component with a log-normal distribution. AME is detected in excess of $20\,\sigma$ at degree-scales around the entirety of the ring along photodissociation regions (PDRs), with three primary bright regions containing dark clouds. A radial decrease is observed in the AME peak frequency from $\approx35\,$GHz near the free-free region to $\approx21\,$GHz in the outer regions of the ring, which is the first detection of AME spectral variations across a single region. A strong correlation between AME peak frequency, emission measure and dust temperature is an indication for the dependence of the AME peak frequency on the local radiation field. The AME amplitude normalised by the optical depth is also strongly correlated with the radiation field, giving an overall picture consistent with spinning dust where the local radiation field plays a key role.
- [54] arXiv:2001.07175 [pdf]
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Title: An Eclipsing Substellar Binary in a Young Triple System discovered by SPECULOOSAuthors: Amaury H.M.J. Triaud, Adam J. Burgasser, Artem Burdanov, Vedad Kunovac Hodžić, Roi Alonso, Daniella Bardalez Gagliuffi, Laetitia Delrez, Brice-Olivier Demory, Julien de Wit, Elsa Ducrot, Frederic V. Hessman, Tim-Oliver Husser, Emmanuël Jehin, Peter P. Pedersen, Didier Queloz, James McCormac, Catriona Murray, Daniel Sebastian, Samantha Thompson, Valérie Van Grootel, Michaël GillonComments: preprint to Nature AstronomySubjects: Solar and Stellar Astrophysics (astro-ph.SR); Earth and Planetary Astrophysics (astro-ph.EP)
Mass, radius, and age are three of the most fundamental parameters for celestial objects, enabling studies of the evolution and internal physics of stars, brown dwarfs, and planets. Brown dwarfs are hydrogen-rich objects that are unable to sustain core fusion reactions but are supported from collapse by electron degeneracy pressure. As they age, brown dwarfs cool, reducing their radius and luminosity. Young exoplanets follow a similar behaviour. Brown dwarf evolutionary models are relied upon to infer the masses, radii and ages of these objects. Similar models are used to infer the mass and radius of directly imaged exoplanets. Unfortunately, only sparse empirical mass, radius and age measurements are currently available, and the models remain mostly unvalidated. Double-line eclipsing binaries provide the most direct route for the absolute determination of the masses and radii of stars. Here, we report the SPECULOOS discovery of 2M1510A, a nearby, eclipsing, double-line brown dwarf binary, with a widely-separated tertiary brown dwarf companion. We also find that the system is a member of the $45\pm5$ Myr-old moving group, Argus. The system's age matches those of currently known directly-imaged exoplanets. 2M1510A provides an opportunity to benchmark evolutionary models of brown dwarfs and young planets. We find that widely-used evolutionary models do reproduce the mass, radius and age of the binary components remarkably well, but overestimate the luminosity by up to 0.65 magnitudes, which could result in underestimated photometric masses for directly-imaged exoplanets and young field brown dwarfs by 20 to 35%.
- [55] arXiv:2001.07182 [pdf, ps, other]
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Title: Could quasar lensing time delays hint to cored dark matter halos, instead of $H_0$ tension?Comments: 9 pages, 3 figuresSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Astrophysics of Galaxies (astro-ph.GA); High Energy Physics - Phenomenology (hep-ph)
The time delay measured between the images of gravitationally lensed quasars probes a combination of the angular diameter distance to the source-lens system and the mass density profile of the lens. Observational campaigns to measure such systems have reported a determination of the Hubble parameter $H_0$ that shows significant tension with independent determination based on the cosmic microwave background (CMB) and large scale structure (LSS). We show that lens mass models that exhibit a cored component, coexisting with a stellar cusp, probe a degenerate direction in the lens model parameter space, being an approximate mass sheet transformation. This family of lens models has not been considered by the cosmographic analyses. Once added to the model, the cosmographic error budget should become dependent on stellar kinematics uncertainties. We propose that a dark matter core coexisting with a stellar cusp could bring the lensing measurements of $H_0$ to accord with the CMB/LSS value.
- [56] arXiv:2001.07196 [pdf, other]
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Title: Detection of neutral atomic species in the ultra-hot jupiter WASP-121bComments: 15 pages, 14 figures, submitted to MNRAS after addressing reviewer commentsSubjects: Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)
The class of ultra-hot Jupiters comprises giant exoplanets undergoing intense irradiation from their host stars. They have proved to be a particularly interesting population for their orbital and atmospheric properties. One such planet, WASP-121~b, is in a highly misaligned orbit close to its Roche limit, and its atmosphere exhibits a thermal inversion. These properties make WASP-121~b an interesting target for additional atmospheric characterization. In this paper, we present analysis of archival high-resolution optical spectra obtained during transits of WASP-121~b. Artifacts from the Rossiter-McLaughlin effect and Center-to-Limb Variation are deemed negligible. However, we discuss scenarios where these effects warrant more careful treatment by modeling the WASP-121 system and varying its properties. We report a new detection of atmospheric absorption from H$\alpha$ in the planet with a transit depth of $1.87\pm0.11\%$. We further confirm a previous detection of the Na I doublet, and report a new detection of Fe I via cross-correlation with a model template. We attribute the H$\alpha$ absorption to an extended Hydrogen atmosphere, potentially undergoing escape, and the Fe I to equilibrium chemistry at the planetary photosphere. These detections help to constrain the composition and chemical processes in the atmosphere of WASP-121~b.
- [57] arXiv:2001.07214 [pdf, other]
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Title: The effects of subgrid models on the properties of giant molecular clouds in galaxy formation simulationsComments: 11 pages, 8 figures, MNRAS submittedSubjects: Astrophysics of Galaxies (astro-ph.GA)
Recent cosmological hydrodynamical simulations are able to reproduce numerous statistical properties of galaxies that are consistent with observational data. Yet, the adopted subgrid models strongly affect the simulation outcomes, limiting the predictive power of these simulations. In this work, we perform a suite of isolated galactic disk simulations under the {\it SMUGGLE} framework and investigate how different subgrid models affect the properties of giant molecular clouds (GMCs). We employ {\sc astrodendro}, a hierarchical clump-finding algorithm, to identify GMCs in the simulations. We find that different choices of subgrid star formation efficiency, $\epsilon_{\rm ff}$, and stellar feedback channels, yield dramatically different mass and spatial distributions for the GMC populations. Without feedback, the mass function of GMCs has a shallower power-law slope and extends to higher mass ranges compared to runs with feedback. Moreover, higher $\epsilon_{\rm ff}$ results in faster molecular gas consumption and steeper mass function slopes. Feedback also suppresses power in the two-point correlation function (TPCF) of the spatial distribution of GMCs. Specifically, radiative feedback strongly reduces the TPCF on scales below 0.2~kpc, while supernova feedback reduces power on scales above 0.2~kpc. Finally, runs with higher $\epsilon_{\rm ff}$ exhibit a higher TPCF than runs with lower $\epsilon_{\rm ff}$, because the dense gas is depleted more efficiently thereby facilitating the formation of well-structured supernova bubbles. We argue that comparing simulated and observed GMC populations can help better constrain subgrid models in the next-generation of galaxy formation simulations.
- [58] arXiv:2001.07215 [pdf, other]
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Title: High-resolution spectroscopy of the GD-1 stellar stream localizes the perturber near the orbital plane of SagittariusAuthors: Ana Bonaca, Charlie Conroy, David W. Hogg, Phillip A. Cargile, Nelson Caldwell, Rohan P. Naidu, Adrian M. Price-Whelan, Joshua S. Speagle, Benjamin D. JohnsonComments: submitted to AAS JournalsSubjects: Astrophysics of Galaxies (astro-ph.GA); Solar and Stellar Astrophysics (astro-ph.SR); High Energy Physics - Phenomenology (hep-ph)
The $100^\circ$-long thin stellar stream in the Milky Way halo, GD-1, has an ensemble of features that may be due to dynamical interactions. Using high-resolution MMT/Hectochelle spectroscopy we show that a spur of GD-1-like stars outside of the main stream are kinematically and chemically consistent with the main stream. In the spur, as in the main stream, GD-1 has a low intrinsic radial velocity dispersion, $\sigma_{V_r}\lesssim1\,\rm km\,s^{-1}$, is metal-poor, $\rm [Fe/H]\approx-2.3$, with little $\rm [Fe/H]$ spread and some variation in $\rm [\alpha/Fe]$ abundances, which point to a common globular cluster progenitor. At a fixed location along the stream, the median radial velocity offset between the spur and the main stream is smaller than $0.5\,\rm km\,s^{-1}$, comparable to the measurement uncertainty. A flyby of a massive, compact object can change orbits of stars in a stellar stream and produce features like the spur observed in GD-1. In this scenario, the radial velocity of the GD-1 spur relative to the stream constrains the orbit of the perturber and its current on-sky position to $\approx5,000\,\rm deg^2$. The family of acceptable perturber orbits overlaps the stellar and dark-matter debris of the Sagittarius dwarf galaxy in present-day position and velocity. This suggests that GD-1 may have been perturbed by a globular cluster or an extremely compact dark-matter subhalo formerly associated with Sagittarius.
- [59] arXiv:2001.07216 [pdf, ps, other]
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Title: On The Red Supergiant ProblemAuthors: C. S. Kochanek (1) ((1) Dept. of Astronomy, The Ohio State University)Comments: submitted to MNRASSubjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA)
We examine the problem of estimating the mass range corresponding to the observed red supergiant (RSG) progenitors of Type IIP supernovae. Using Monte Carlo simulations designed to reproduce the properties of the observations, we find that the approach of Davies & Beasor (2018) significantly overestimates the maximum mass, yielding an upper limit of Mh/Msun=20.5+/-2.6 for an input population with Mh/Msun=18. Our preferred Bayesian approach does better, with Mh/Msun=18.6+/-2.1 for the same input populations, but also tends to overestimate Mh. For the actual progenitor sample and a Salpeter initial mass function we find Mh/Msun=19.01-2.04+4.04 for the Eldridge et al. (2004) mass-luminosity relation used by Smartt et al. (2009) and Davies & Beasor (2018), and Mh/Msun=21.28_-2.28+4.52 for the Sukhbold et al. (2018) mass-luminosity relation. Based on the Monte Carlo simulations, we estimate that these are overestimated by 3.3+/-0.8Mh. The red supergiant problem remains.
- [60] arXiv:2001.07217 [pdf, other]
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Title: Close galaxy pairs with accurate photometric redshiftsAuthors: Facundo Rodriguez, Elizabeth J. Gonzalez, Ana L. O'Mill, Enrique Gaztañaga, Pablo Fosalba, Diego García Lambas, Mar Mezcua, Małgorzata SiudekComments: 10 pages, 12 Figures. Accepted for publication in A&ASubjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
Context. Studies of galaxy pairs can provide valuable information to jointly understand the formation and evolution of galaxies and galaxy groups. Consequently, taking into account the new high precision photo-z surveys, it is important to have reliable and tested methods that allow us to properly identify these systems and estimate their total masses and other properties. Aims. In view of the forthcoming Physics of the Accelerating Universe Survey (PAUS) we propose and evaluate the performance of an identification algorithm of projected close isolated galaxy pairs. We expect that the photometric selected systems can adequately reproduce the observational properties and the inferred lensing mass - luminosity relation of a pair of truly bound galaxies that are hosted by the same dark matter halo. Methods. We develop an identification algorithm that considers the projected distance between the galaxies, the projected velocity difference and an isolation criteria in order to restrict the sample to isolated systems. We apply our identification algorithm using a mock galaxy catalog that mimics the features of PAUS. To evaluate the feasibility of our pair finder, we compare the identified photometric samples with a test sample that considers that both members are included in the same halo. Also, taking advantage of the lensing properties provided by the mock catalog, we apply a weak lensing analysis to determine the mass of the selected systems. Results. Photometric selected samples tend to show high purity values, but tend to misidentify truly bounded pairs as the photometric redshift errors increase. Nevertheless, overall properties such as the luminosity and mass distributions are successfully reproduced. We also accurately reproduce the lensing mass - luminosity relation as expected for galaxy pairs located in the same halo.
- [61] arXiv:2001.07218 [pdf, other]
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Title: The WISSH quasars project VII. Outflows and metals in the circumgalactic medium around the hyper-luminous z~3.6 quasar J1538+08Authors: A. Travascio, L. Zappacosta, S. Cantalupo, E. Piconcelli, F. Arrigoni Battaia, M. Ginolfi, M. Bischetti, G. Vietri, A. Bongiorno, V. D'Odorico, F. Duras, C. Feruglio, C. Vignali, F. FioreComments: 14 pages, 16 figures, 2 tables. Accepted for publication in A&A JournalSubjects: Astrophysics of Galaxies (astro-ph.GA)
During the last years, Ly$\alpha$ nebulae have been routinely detected around high-z, radio-quiet quasars (RQQs) thanks to the advent of sensitive integral field spectrographs. Constraining the physical properties of the Ly$\alpha$ nebulae is crucial for a full understanding of the circum-galactic medium (CGM), which is a venue of feeding and feedback processes. The most luminous quasars are privileged test-beds to study these processes, given their large ionizing fluxes and dense CGM environments in which they are expected to be embedded. We aim at characterizing the rest-frame UV emission lines in the CGM around a hyper-luminous, broad emission line, RQQ at z~3.6, that exhibits powerful outflows at both nuclear and host galaxy scales. We analyze VLT/MUSE observations of the quasar J1538+08 and perform a search for extended UV emission lines to characterize its morphology, emissivity, kinematics and metal content. We report the discovery of a very luminous ($\sim2 \times10^{44}~erg~s^{-1}$), giant Ly$\alpha$ nebula and a likely associated extended CIV nebula. The Ly$\alpha$ nebula emission exhibits moderate blueshift compared with the quasar systemic redshift and large average velocity dispersion ($\sigma_{v}$ ~700 $km~s^{-1}$) across the nebula, while the CIV nebula shows $\sigma_{v}$~$350~km~s^{-1}$. The Ly$\alpha$ line profile exhibits a significant asymmetry towards negative velocity values at 20-30 kpc south of the quasar and is well parameterized by two Gaussian components: a narrow ($\sigma$~$470~km~s^{-1}$) systemic one plus a broad ($\sigma$~1200 $km~s^{-1}$), blueshifted (~1500 $km~s^{-1}$) one. Our analysis of the MUSE observation of J1538+08 reveals metal-enriched CGM around this hyper-luminous quasar and our detection of blueshifted emission in the line profile of the Ly$\alpha$ nebula suggests that powerful nuclear outflows can propagate through the CGM over tens of kpc.
- [62] arXiv:2001.07222 [pdf, ps, other]
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Title: A new mass-loss rate prescription for red supergiantsAuthors: Emma R. Beasor, Ben Davies, Nathan Smith, Jacco Th. van Loon, Robert D. Gehrz, Donald F. FigerComments: 13 pages, accepted to MNRASSubjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA)
Evolutionary models have shown the substantial effect that strong mass-loss rates ($\dot{M}$) can have on the fate of massive stars. Red supergiant (RSG) mass-loss is poorly understood theoretically, and so stellar models rely on purely empirical \mdot-luminosity relations to calculate evolution. Empirical prescriptions usually scale with luminosity and effective temperature, but $\dot{M}$ should also depend on the current mass and hence the surface gravity of the star, yielding more than one possible $\dot{M}$ for the same position on the Hertzsprung-Russell diagram. One can solve this degeneracy by measuring $\dot{M}$ for RSGs that reside in clusters, where age and initial mass ($M_{\rm init}$) are known. In this paper we derive $\dot{M}$ values and luminosities for RSGs in two clusters, NGC 2004 and RSGC1. Using newly derived $M_{\rm init}$ measurements, we combine the results with those of clusters with a range of ages and derive an $M_{\rm init}$-dependent $\dot{M}$-prescription. When comparing this new prescription to the treatment of mass-loss currently implemented in evolutionary models, we find models drastically over-predict the total mass-loss, by up to a factor of 20. Importantly, the most massive RSGs experience the largest downward revision in their mass-loss rates, drastically changing the impact of wind mass-loss on their evolution. Our results suggest that for most initial masses of RSG progenitors, quiescent mass-loss during the RSG phase is not effective at removing a significant fraction of the H-envelope prior to core-collapse, and we discuss the implications of this for stellar evolution and observations of SNe and SN progenitors.
- [63] arXiv:2001.07224 [pdf, ps, other]
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Title: High spin temperatures at large impact parameters: Ionisation in the outskirts of galaxiesAuthors: S. J. CurranComments: Accepted by A&ASubjects: Astrophysics of Galaxies (astro-ph.GA)
By including the most recent observations of HI 21-cm absorption through near-by galactic disks, we confirm our previous assertion that there is an anti-correlation between the abundance of cool neutral atomic gas and impact parameter. Comparing the measured neutral hydrogen column densities of the sample with the absorption strength, we find a peak in the mean spin temperature of ~2310 K at an impact parameter of ~ 14 kpc, with > 1000 K in the remainder of the disk. This is significantly different to the spin temperature distribution in the Milky Way, which exhibits a constant ~ 250 - 400 K over 8 - 25 kpc. The measured column densities may, however, suffer from beam dilution, which we show appears to be the case for the observations of HI 21-cm emission in which the beam subtends radii of > 10 kpc. We therefore apply the column density profile of the Milky Way, in addition to the mean of the sample, observed at sufficiently high resolution, and the mean profile for the near-by galaxies in the IllustrisTNG simulations. All of the models yield a peak in the mean spin temperature at similar radii/impact parameters (10 - 15 kpc) as the measured column densities. These radii are similar to those of the spiral arms where HII regions are often concentrated. We therefore suggest that the elevated spin temperatures trace the HII regions observed in the outer disk of many spiral galaxies.
- [64] arXiv:2001.07257 [pdf, other]
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Title: The extreme CNO-enhanced composition of the primitive iron-poor dwarf star J0815+4729\footnote{Based on observations made with Keck I telescope at Mauna Kea Observatory, Hawaii, USA}Authors: Jonay~I. González Hernández, David~S. Aguado, Carlos Allende Prieto, Adam~J. Burgasser, Rafael ReboloComments: Accepted for publication in The Astrophysical Journal LettersSubjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA)
We present an analysis of high-resolution Keck/HIRES spectroscopic observations of J0815+4729, an extremely carbon-enhanced, iron-poor dwarf star. These high-quality data allow us to derive a metallicity of [Fe/H]$=-5.49{\pm}0.14$ from the three strongest \ion{Fe}{1} lines and to measure a high [Ca/Fe]~$=0.75{\pm}0.14$. The large carbon abundance of A(C)~$=7.43{\pm}0.17$ (or [C/Fe]~$\sim 4.49{\pm}0.11$) places this star in the upper boundary of the low-carbon band in the A(C)-[Fe/H] diagram, suggesting no contamination from a binary AGB companion. We detect the oxygen triplet at 777nm for the first time in an ultra-metal poor star, indicating a large oxygen-to-iron abundance ratio of [O/Fe]~$=4.03{\pm}0.12$ (A(O)~$=7.23{\pm}0.14$), significantly higher than the previously most metal-poor dwarf J2209-0028 with an oxygen triplet detection with [O/Fe]~$\sim2.2$~dex at [Fe/H]~$\sim -3.9$. Nitrogen is also dramatically enhanced with (A(N)~$=6.75{\pm}0.08$) and an abundance ratio [N/Fe]~$\sim 4.41{\pm}0.08$. We also detect Ca, Na and Mg, while provide upper limits for eight other elements. The abundance pattern of J0815+4729 resembles that of HE~1327-2326, indicating that both are second-generation stars contaminated by a $\sim 21-27$~\msun~single, zero-metallicity low-energy supernova with very little mixing and substantial fallback. The absence of lithium implies an upper-limit abundance A(Li)~$<1.3$~dex, about 0.7~dex below the detected Li abundance in J0023+0307 which has a similar metallicity, exacerbating the cosmological lithium problem.
- [65] arXiv:2001.07262 [pdf, other]
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Title: Revisit of Y-junctions for strings with currents: transonic elastic caseAuthors: I. Yu. RybakComments: 10 pages, 3 figuresSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Theory (hep-th)
We studied the formation of Y-junctions for transonic elastic strings. Using the general solution for this type of strings, which is described by left- and right-moving modes, we obtained the dynamics of Y-junctions. Considering the linearized ansatz for straight strings, we constructed the region in "angle-velocity" space for which the formation of Y-junctions due to strings collisions is allowed. We argue that the obtained result is valid for all current carrying straight strings.
- [66] arXiv:2001.07285 [pdf, other]
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Title: Spectral evolution of the ultraluminous X-ray sources M82 X-1 and X-2Authors: Murray Brightman, Dominic J. Walton, Yanjun Xu, Hannah P. Earnshaw, Fiona, A. Harrison, Daniel Stern, Didier BarretComments: In press at ApJSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
M82 hosts two well-known ultraluminous X-ray sources (ULXs). X-1, an intermediate-mass black hole (IMBH) candidate, and X-2, an ultraluminous X-ray pulsar (ULXP). Here we present a broadband X-ray spectral analysis of both sources based on ten observations made simultaneously with Chandra and NuSTAR. Chandra provides the high spatial resolution to resolve the crowded field in the 0.5--8 keV band, and NuSTAR provides the sensitive hard X-ray spectral data, extending the bandpass of our study above 10 keV. The observations, taken in the period 2015--2016, cover a period of flaring from X-1, allowing us to study the spectral evolution of this source with luminosity. During four of these observations, X-2 was found to be at a low flux level, allowing an unambiguous view of the emission from X-1. We find that the broadband X-ray emission from X-1 is consistent with that seen in other ULXs observed in detail with NuSTAR, with a spectrum that includes a broadened disk-like component and a high-energy tail. We find that the luminosity of the disk scales with inner disk temperature as L~T^-3/2 contrary to expectations of a standard accretion disk and previous results. These findings rule out a thermal state for sub-Eddington accretion and therefore do not support M82 X-1 as an IMBH candidate. We also find evidence that the neutral column density of the material in the line of sight increases with L$_X$, perhaps due to an increased mass outflow with accretion rate. For X-2, we do not find any significant spectral evolution, but we find the spectral parameters of the phase-averaged broadband emission are consistent with the pulsed emission at the highest X-ray luminosities.
- [67] arXiv:2001.07288 [pdf]
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Title: The Spin-Period History of Intermediate PolarsAuthors: Joseph Patterson (1), Enrique de Miguel (2), Jonathan Kemp (3), Shawn Dvorak (4), Berto Monard (4), Franz-Josef Hambsch (4), Tonny Vanmunster (4), David R. Skillman (4), David Cejudo (4), Tut Campbell (4), George Roberts (4), Jim Jones (4), Lewis M. Cook (4), Greg Bolt (4), Robert Rea (4), Joseph Ulowetz (4), Thomas Krajci (4), Kenneth Menzies (4), Simon Lowther (4), William Goff (4), William Stein (4), Matt A. Wood (5), Gordon Myers (4), Geoffrey Stone (4), Helena Uthas (6), Emir Karamehmetoglu (7), Jim Seargeant (4), Jennie McCormick (4) ((1) Columbia Univ., (2) Univ. de Huelva, (3) Middlebury Coll., (4) Center for Backyard Astrophysics, (5) Texas A&M Univ.-Commerce, (6) Viktor Rydberg-Djursholm, (7) Aarhus Univ.)Comments: PDF, 13 pages, 1 table, 2 figures; submitted, ApJ; more info at this http URLSubjects: Solar and Stellar Astrophysics (astro-ph.SR)
We report the detailed history of spin-period changes in five intermediate polars (DQ Herculis, AO Piscium, FO Aquarii, V1223 Sagittarii, and BG Canis Minoris) during the 30-60 years since their original discovery. Most are slowly spinning up, although there are sometimes years-long episodes of spin-down. This is supportive of the idea that the underlying magnetic white dwarfs are near spin equilibrium. In addition to the ~40 stars sharing many properties and defined by their strong, pulsed X-ray emission, there are a few rotating much faster (P<80 s), whose membership in the class is still in doubt -- and who are overdue for closer study.
- [68] arXiv:2001.07291 [pdf, other]
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Title: Multi-scale dynamics of magnetic flux tubes and inverse magnetic energy transferComments: 30 pages, 18 figures, submitted for publicationSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); Plasma Physics (physics.plasm-ph)
We report on an analytical and numerical study of the dynamics of a three-dimensional array of identical magnetic flux tubes in the reduced-magnetohydrodynamic description of the plasma. We propose that the long time evolution of this system is dictated by flux-tube mergers; and that such mergers are dynamically constrained by the conservation of the pertinent (ideal) invariant, {\it viz.} the magnetic potential and axial fluxes of each tube. In the direction perpendicular to the merging plane, flux tubes evolve in critically-balanced fashion. These notions allow us to construct an analytical model for how quantities such as the magnetic energy and the energy-containing scale evolve as functions of time. Of particular importance is the conclusion that, like its two-dimensional counterpart, this system exhibits an inverse transfer of magnetic energy that terminates only at the system scale. We perform direct numerical simulations that confirm these predictions and reveal other interesting aspects of the evolution of the system. We find, for example, that the early time evolution is characterized by a sharp decay of the initial magnetic energy, which we attribute to the ubiquitous formation of current sheets. We also show that a quantitatively similar inverse transfer of magnetic energy is observed when the initial condition is a random, small-scale magnetic seed field.
- [69] arXiv:2001.07303 [pdf, other]
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Title: A Massive Star's Dying Breaths: Pulsating Red Supergaints and Their Resulting Type IIP SupernovaeComments: 9 pages, 8 figures, submitted to ApJ. Comments welcomeSubjects: Solar and Stellar Astrophysics (astro-ph.SR); High Energy Astrophysical Phenomena (astro-ph.HE)
Massive stars undergo fundamental-mode and first-overtone radial pulsations with periods of 100-1000 days as Red Supergiants (RSGs). At large amplitudes, these pulsations substantially modify the outer envelope's density structure encountered by the outgoing shock wave from the eventual core collapse of these $M>9M_\odot$ stars. Using Modules for Experiments in Stellar Astrophysics (MESA), we model the effects of fundamental-mode and first-overtone pulsations in the RSG envelopes, and the resulting Type IIP supernovae (SNe) using MESA+STELLA. We find that, in the case of fundamental mode pulsations, SN plateau observables such as the luminosity at day 50, $L_{50}$, time-integrated shock energy $ET$, and plateau duration $t_{\rm p}$ are consistent with radial scalings derived considering explosions of non-pulsating stars. Namely, most of the effect of the pulsation is consistent with the behavior expected for a star of a different size at the time of explosion. However, in the case of overtone pulsations, the Lagrangian displacement is not monotonic. Therefore, in such cases, excessively bright or faint SN emission at different times reflects the underdense or overdense structure of the emitting region near the SN photosphere.
- [70] arXiv:2001.07328 [pdf, other]
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Title: The nuclear region of NGC 613. I -- Multiwavelength analysisComments: 21 pages, 22 figures, 4 tablesSubjects: Astrophysics of Galaxies (astro-ph.GA)
In this paper, we report a detailed study with a variety of data from optical, near-infrared, X-ray, and radio telescopes of the nuclear region of the galaxy NGC 613 with the aim of understanding its complexity. We detected an extended stellar emission in the nucleus that, at first, appears to be, in the optical band, two stellar nuclei separated by a stream of dust. The active galactic nucleus (AGN) is identified as a variable point-like source between these two stellar components. There is a central hard X-ray emission and an extended soft X-ray emission that closely coincides with the ionization cone, as seen in the [O III]$\lambda$5007 emission. The centroid of the [O I]$\lambda$6300 emission does not coincide with the AGN, being shifted by 0.24 arcsec towards the ionization cone; this shift is probably caused by a combination of differential dust extinction together with emission and reflection in the ionization cone. The optical spectra extracted from the central region are typical of low-ionization nuclear emission-line regions. We also identify 10 H II regions, eight of them in a star forming ring that is visible in Br$\gamma$, [Fe II]$\lambda$16436 and molecular CO(3-2) images observed in previous studies. Such a ring also presents weak hard X-ray emission, probably associated with supernova remnants, not detected in other studies. The position of the AGN coincides with the centre of a nuclear spiral (detected in previous works) that brings gas and dust from the bar to the nucleus, causing the high extinction in this area.
- [71] arXiv:2001.07345 [pdf, other]
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Title: TOI-257b (HD 19916b): A Warm sub-Saturn on a Moderately Eccentric Orbit Around an Evolved F-type StarAuthors: Brett C. Addison, Duncan J. Wright, Belinda A. Nicholson, Bryson Cale, Teo Mocnik, Daniel Huber, Peter Plavchan, Robert A. Wittenmyer, Andrew Vanderburg, William J. Chaplin, Ashley Chontos, Jake T. Clark, Jason D. Eastman, Carl Ziegler, Rafael Brahm, Bradley D. Carter, Mathieu Clerte, Néstor Espinoza, Jonathan Horner, John Bentley, Stephen R. Kane, John F. Kielkopf, Emilie Laychock, Matthew W. Mengel, Jack Okumura, Keivan G. Stassun, Timothy R. Bedding, Brendan P. Bowler, Andrius Burnelis, Michaela Collins, Ian Crossfield, Allen B. Davis, Dag Evensberget, Alexis Heitzmann, Steve B. Howell, Nicholas Law, Andrew W. Mann, Stephen Marsden, James O'Connor, Avi Shporer, Catherine Stevens, C.G. Tinney, Christopher Tylor, Songhu Wang, Hui Zhang, Thomas Henning, Diana Kossakowski, George Ricker, et al. (39 additional authors not shown)Comments: 21 pages, 20 figures, 5 tables, submitted to MNRAS. Feedback welcome!Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)
We report the discovery of a warm sub-Saturn, TOI-257b (HD 19916b), based on data from NASA's Transiting Exoplanet Survey Satellite (TESS). The transit signal was detected by TESS and confirmed to be of planetary origin based on radial-velocity observations with the Minerva-Australis telescope array. An analysis of the TESS photometry, the Minerva-Australis, FEROS, and HARPS radial velocities, and the asteroseismic data of the stellar oscillations reveals that TOI-257b has a mass of $M_P=0.134^{+0.023}_{-0.022}$$\rm{M_J}$ ($42.6^{+7.3}_{-7.0}$$\rm{M_{\oplus}}$), a radius of $R_P=0.626^{+0.013}_{-0.012}$$\rm{R_J}$ ($7.02^{+0.15}_{-0.13}$$\rm{R_{\oplus}}$), and an orbit with eccentricity $0.242^{+0.040}_{-0.065}$ and period $18.38827\pm0.00072$$\rm{days}$. TOI-257b orbits a bright ($\mathrm{V}=7.570$mag) somewhat evolved late F-type star with $M_*=1.390\pm0.046$$\rm{M_{\odot}}$, $R_*=1.888\pm0.033$$\rm{R_{\odot}}$, $T_{\rm eff}=6075\pm90$$\rm{K}$, and $v\sin{i}=11.3\pm0.5$km/s. Additionally, we statistically validate a second non-transiting sub-Saturn mass planet on a $\sim71$day orbit using the radial velocity data. This system joins the ranks of a small number of exoplanet host stars that have been characterized with asteroseismology. Warm sub-Saturns are rare in the known sample of exoplanets, and thus the discovery of TOI-257b is important in the context of future work studying the formation and migration history of similar planetary systems.
- [72] arXiv:2001.07347 [pdf, other]
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Title: Discovery of a Remarkably Powerful Broad Absorption Line Quasar Outflow in SDSS J135246.37+423923.5Authors: Hyunseop Choi, Karen M. Leighly, Donald M. Terndrup, Sarah C. Gallagher, Gordon T. RichardsSubjects: Astrophysics of Galaxies (astro-ph.GA)
Broad absorption line (BAL) features in quasar spectra reveal an unambiguous signature of energetic outflows from central supermassive black holes, and thus BAL quasars are prime targets for investigating the potential process of luminous quasar feedback on galaxies. We analyzed the rest-UV spectrum of an "overlapping trough" iron low-ionization broad absorption line quasar (FeLoBAL) SDSS J135246.37+423923.5 using the novel spectral synthesis code SimBAL (Leighly et al. 2018) and discovered an extraordinarily fast and energetic BAL outflow. Our analysis revealed outflow velocities reaching $\sim -38000\rm \, km\, s^{-1}$ with a velocity width of $\sim 10000\rm \, km\, s^{-1}$ which is the largest FeLoBAL outflow velocity measured to date. The column density of the outflow gas is log$N_H\sim23.2\,[\rm cm^{-1}]$ with the log kinetic luminosity $\log L_{KE}\sim48.1$ [erg $\rm s^{-1}$] which exceeds the bolometric luminosity of the quasar and is energetic enough to effectively drive quasar feedback. The energy estimate for the outflow is far greater than the estimates from any BAL object previously reported.
The object also shows "anomalous reddening" and a significant scattered component that we were able to model with SimBAL. We found the first definitive case for radiation filtering in an additional zero-velocity absorption component that required an absorbed continuum to produce the particular absorption lines observed (MgII, AlIII and AlII) without also producing the high ionization lines such as CIV. - [73] arXiv:2001.07367 [pdf, other]
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Title: Kinematic unrest of low mass galaxy groupsAuthors: G. Gozaliasl, A. Finoguenov, H. G. Khosroshahi, C. Laigle, C. C. Kirkpatrick, K. Kiiveri, J. Devriendt, Y. Dubois, J. AhorantaComments: 9 pages, 5 figuresSubjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
In an effort to better understand the formation of galaxy groups, we examine the kinematics of a large sample of spectroscopically confirmed X-ray galaxy groups in the Cosmic Evolution Survey (COSMOS) with a high sampling of galaxy group members up to $z=1$. We compare our results with predictions from the cosmological hydrodynamical simulation of {\sc Horizon-AGN}. Using a phase-space analysis of dynamics of groups with halo masses of $M_{\mathrm{200c}}\sim 10^{12.6}-10^{14.50}M_\odot$, we show that the brightest group galaxies (BGG) in low mass galaxy groups ($M_{\mathrm{200c}}<2 \times 10^{13} M_\odot$) have larger proper motions relative to the group velocity dispersion than high mass groups. The dispersion in the ratio of the BGG proper velocity to the velocity dispersion of the group, $\sigma_{\mathrm{BGG}}/\sigma_{group}$, is on average $1.48 \pm 0.13$ for low mass groups and $1.01 \pm 0.09$ for high mass groups. A comparative analysis of the {\sc Horizon-AGN} simulation reveals a similar increase in the spread of peculiar velocities of BGGs with decreasing group mass, though consistency in the amplitude, shape, and mode of the BGG peculiar velocity distribution is only achieved for high mass groups. The groups hosting a BGG with a large peculiar velocity are more likely to be offset from the $L_x-\sigma_{v}$ relation; this is probably because the peculiar motion of the BGG is influenced by the accretion of new members.
- [74] arXiv:2001.07398 [pdf, ps, other]
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Title: Study of open cluster King 13 using CCD VI, 2MASS and Gaia DR2 AstrometryComments: 32 pages (including figures), 13 figures, This paper is accepted in New Astronomy for the publicationSubjects: Astrophysics of Galaxies (astro-ph.GA)
In this paper, we present astrophysical parameters of the open cluster King 13 based on the VI CCD and 2MASS JHKs photometric data. This is a poorly studied cluster, for which new results have been found in the present work. To identify probable members, we use proper motion data from Gaia DR2 catalogue. The mean proper motion of the cluster is determined as -2.8 \pm 0.2 and -0.88 \pm 0.14 mas yr{-1} and cluster extent is derived as 3'.2. Using color-magnitude diagrams, we estimate the age and distance of the cluster as 510 \pm 60 Myr and 3.84 \pm 0.15 kpc respectively. Interstellar reddening E(B-V) in the direction of the cluster is determined as 0.80 \pm 0.2 mag using color-color diagram. Mass function slope of the cluster is found to be comparable with the Salpeter value. The total mass of this cluster is derived as 270 M_{\odot}. The present analysis shows that King 13 is a dynamically relaxed cluster.
- [75] arXiv:2001.07435 [pdf, ps, other]
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Title: The "dynamical clock": dating the internal dynamical evolution of star clusters with Blue Straggler StarsAuthors: F. R. Ferraro (1,2), B. Lanzoni (1,2), E. Dalessandro (2) (1 Bologna University, Italy, (2) INAF-OAS, Bologna, Italy)Comments: 15 pages, 12 figures, in press on Rendiconti Lincei, Scienze Fisiche e NaturaliSubjects: Astrophysics of Galaxies (astro-ph.GA); Solar and Stellar Astrophysics (astro-ph.SR)
We discuss the observational properties of a special class of objects (the so-called "Blue Straggler Stars", BSSs) in the framework of using this stellar population as probe of the dynamical processes occurring in high-density stellar systems. Indeed, the shape of the BSS radial distribution and their level of central concentration are powerful tracers of the stage of dynamical evolution reached by the host cluster since formation. Hence, they can be used as empirical chronometers able to measure the dynamical age of stellar systems. In addition, the presence of a double BSS sequence in the color-magnitude diagram is likely the signature of the most extreme dynamical process occurring in globular cluster life: the core collapse event. Such a feature can therefore be used to reveal the occurrence of this process and, for the first time, even date it.
- [76] arXiv:2001.07446 [pdf, other]
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Title: Extreme variability in an active galactic nucleus: Gaia16aaxAuthors: G. Cannizzaro, M. Fraser, P. G. Jonker, J. E. Pringle, S. Mattila, P. C. Hewett, T. Wevers, E. Kankare, Z. Kostrzewa-Rutkowska, Ł. Wyrzykowski, F. Onori, J. Harmanen, K. E. S. Ford, B. McKernan, C. J. NixonComments: 21 pages, 17 figure - accepted for publication in MNRAS main journalSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); Astrophysics of Galaxies (astro-ph.GA)
We present the results of a multi-wavelength follow up campaign for the luminous nuclear transient Gaia16aax, which was first identified in January 2016. The transient is spatially consistent with the nucleus of an active galaxy at z=0.25, hosting a black hole of mass $\rm \sim6\times10^8M_\odot$. The nucleus brightened by more than 1 magnitude in the Gaia G-band over a timescale of less than one year, before fading back to its pre-outburst state over the following three years. The optical spectra of the source show broad Balmer lines similar to the ones present in a pre-outburst spectrum. During the outburst, the $\rm H\alpha$ and $\rm H\beta$ emission lines develop a secondary peak. We also report on the discovery of two transients with similar light curve evolution and spectra: Gaia16aka and Gaia16ajq. We consider possible scenarios to explain the observed outbursts. We exclude that the transient event could be caused by a microlensing event, variable dust absorption or a tidal encounter between a neutron star and a stellar mass black hole in the accretion disk. We consider variability in the accretion flow in the inner part of the disk, or a tidal disruption event of a star $\geq 1 M_{\odot}$ by a rapidly spinning supermassive black hole as the most plausible scenarios. We note that the similarity between the light curves of the three Gaia transients may be a function of the Gaia alerts selection criteria.
- [77] arXiv:2001.07447 [pdf, other]
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Title: Submillimeter Galaxy studies in the next decade: EAO Submillimetre Futures White Paper Series, 2019Comments: 10 pages 3 figures. EAO Submillimetre Futures White Paper Series, 2019Subjects: Astrophysics of Galaxies (astro-ph.GA)
Over the last two decades, the Submillimetre Common-User Bolometer Array (SCUBA) and SCUBA-2 on the James Clerk Maxwell Telescope (JCMT) achieved gread success in discovering the population of dusty starburst galaxies in the early universe. The SCUBA-2 surveys at 450 micron and 850 micron set important constraints on the obscured star formation over cosmic time, and in combination of deep optical and near-IR data, allows the study of protoclusters and structure formation. However, the current submillimeter (submm) surveys by JCMT are still limited by area of sky coverage (confusion limit mapping of only a few deg^2), which prevent a systematic study of large samples of the obscured galaxy population. In this white paper, we review the studies of the submm galaxies with current submillimeter/millimeter (submm/mm) observations, and discuss the important science with the new submm instruments in the next decade. In particular, with a 10 times faster mapping speed of the new camera, we will expect deep 850 micron surveys over 10 to 100 times larger sky area to i) largely increase the sample size of submm detections toward the highest redshift, ii) improve our knowledge of galaxy and structure formation in the early universe.
- [78] arXiv:2001.07452 [pdf, ps, other]
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Title: Identification of QPO frequency of GRS 1915+105 as the relativistic dynamic frequency of a truncated accretion diskComments: 7 Pages, 4 Figures, 1 Table, Accepted for publication in Astrophysical Journal Letters (ApJL)Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)
We have analyzed AstroSat observations of the galactic micro-quasar system GRS 1915+105, when the system exhibited C-type Quasi-periodic Oscillations (QPOs) in the frequency range of 3.4-5.4 Hz. The broad band spectra (1-50 keV) obtained from simultaneous LAXPC and SXT can be well described by a dominant relativistic truncated accretion disk along with thermal Comptonization and reflection. We find that while the QPO frequency depends on the inner radii with a large scatter, a much tighter correlation is obtained when both the inner radii and accretion rate of the disk are taken into account. In fact, the frequency varies just as the dynamic frequency (i.e. the inverse of the sound crossing time) as predicted decades ago by the relativistic standard accretion disk theory for a black hole with spin parameter of ~0.9. We show that this identification has been possible due to the simultaneous broad band spectral coverage with temporal information as obtained from AstroSat.
- [79] arXiv:2001.07459 [pdf, other]
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Title: A model for the onset of self-gravitation and star formation in molecular gas governed by galactic forces: II. the bottleneck to collapse set by cloud-environment decouplingAuthors: Sharon E. Meidt, Simon C. O. Glover, J. M. Diederik Kruijssen, Adam K. Leroy, Erik Rosolowsky, Andreas Schruba, Annie Hughes, Eva Schinnerer, Antonio Usero, Frank Bigiel, Guillermo Blanc, Melanie Chevance, Jerome Pety, Miguel Querejeta, Dyas UtomoComments: Accepted for publication in ApJ, 32 pages, 11 figuresSubjects: Astrophysics of Galaxies (astro-ph.GA)
In Meidt et al. (2018), we showed that gas kinematics on the scale of individual molecular clouds are not dominated by self-gravity but also track a component that originates with orbital motion in the potential of the host galaxy. This agrees with observed cloud line widths, which show systematic variations from virial motions with environment, pointing at the influence of the galaxy potential. In this paper, we hypothesize that these motions act to slow down the collapse of gas and so help regulate star formation. Extending the results of Meidt et al. (2018), we derive a dynamical collapse timescale that approaches the free-fall time only once the gas has fully decoupled from the galactic potential. Using this timescale we make predictions for how the fraction of free-falling, strongly self-gravitating gas varies throughout the disks of star-forming galaxies. We also use this collapse timescale to predict variations in the molecular gas star formation efficiency, which is lowered from a maximum, feedback-regulated level in the presence of strong coupling to the galactic potential. Our model implies that gas can only decouple from the galaxy to collapse and efficiently form stars deep within clouds. We show that this naturally explains the observed drop in star formation rate per unit gas mass in the Milky Way's CMZ and other galaxy centers. The model for a galactic bottleneck to star formation also agrees well with resolved observations of dense gas and star formation in galaxy disks and the properties of local clouds.
- [80] arXiv:2001.07472 [pdf, ps, other]
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Title: Detection of fluorine in hot Extreme Helium StarsComments: 41 pages, 18 figures, 5 tables, Accepted for publication in ApJSubjects: Solar and Stellar Astrophysics (astro-ph.SR)
The main objective of this paper is to explore abundances of fluorine in hot Extreme Helium Stars (EHes). Overabundance of fluorine is a characteristic feature for cool EHes and R Coronae Borealis (RCB) stars and further enforces their close connection. For hot EHes this relationship with the cooler EHes, based on their fluorine abundance is unexplored. We present in this paper the first abundance estimates of fluorine determined from singly ionised fluorine lines (F\,{\sc ii}) for 10 hot EHe stars from optical spectra. Fluorine abundances were determined using the F\,{\sc ii} lines in two windows centered at 3505 \AA \ and 3850 \AA . Six of the 10 stars show significant enhancement of fluorine similar to the cool EHes. Two carbon-poor hot EHes show no signature of fluorine and have a significant low upper limit for the F abundance. These fluorine abundances are compared with the other elemental abundances observed in these stars which provide an idea about the formation and evolution of these stars. The trends of fluorine with C, O, and Ne show that significant helium burning after a CO-He white dwarf merger can account for a majority of the observed abundances. Predictions from simulations of white dwarf mergers are discussed in light of the observed abundances.
- [81] arXiv:2001.07476 [pdf, other]
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Title: Axion Stars Nucleation in Dark Mini-Halos around Primordial Black HolesComments: 6 pages, 3 figuresSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Phenomenology (hep-ph)
We consider a general class of axion models, including the QCD and string axion, in which the PQ symmetry is broken before or during inflation. Assuming the axion is the dominant component of the dark matter, we discuss axion star formation in virialized dark mini-halos around primordial black holes through gravitational Bose-Einstein condensation. We determine the conditions for mini-halos to kinetically produce axion stars before galaxy formation. Today, we expect up to $\sim 10^{17}$ ($\sim 10^9$) axion stars in a radius of 100 parsecs around the sun for the case of the QCD (string) axion.
- [82] arXiv:2001.07486 [pdf, other]
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Title: X-ray properties of dwarf nova EY Cyg and the companion star using an XMM-Newton observationComments: 7 pages, 3 figures, 3 tables. Accepted for publication in a Special Issue of Advances in Space Research, entitled "Nova Eruptions, Cataclysmic Variables and Related Systems: observational vs theoretical challenges in the 2020 era", edited BY S. Balman and P. A. SheaSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
We present the X-ray analysis of dwarf nova EY Cyg using the 45 ks \textit{XMM-Newton} observatory archival data obtained in quiescence. We find orbital modulations in X-rays. We simultaneously fitted EPIC pn, MOS1 and MOS2 data using a model for interstellar medium absorption (\textit{tbabs}) and a multi-temperature plasma emission model with a power-law distribution of temperatures (CEVMKL) as expected from low accretion rate quiescent dwarf novae. The \textit{XMM-Newton} EPIC spectra of the source yields a maximum temperature $kT_{\rm max}$ $\sim$ 14.9$^{+3.3}_{-2.2}$ keV with an unabsorbed X-ray flux and luminosity of (1.8--2.0) $\times$ 10$^{-12}$ ergs$^{-1}$ cm$^{-1}$ and (8.7--9.7) $\times$ 10$^{31}$ ergs$^{-1}$, respectively, in the energy range 0.1 to 50 keV. There is 3--4 sigma excess at energies below 0.5 keV, we model the excess using \textit{MEKAL}, POWERLAW and BBODY models and favor the model \textit{MEKAL} which is physical. According to previous studies, the secondary in this system is thought to be a K-type star which may radiate in the soft X-ray region. The fit with an additive \textit{MEKAL} model gives a temperature of $kT$ $\sim$ 0.1 keV with an unabsorbed X-ray flux and luminosity of (2.7--8.8) $\times$ 10$^{-14}$ ergs$^{-1}$ cm$^{-1}$ and (1.3--4.2) $\times$ 10$^{30}$ ergs$^{-1}$, respectively, for the companion star. Based on the results from the timing and spectral analysis, we highly suggest that the secondary of EY Cyg is a K-type star.
- [83] arXiv:2001.07503 [pdf, ps, other]
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Title: Rapid spectral transition of the black hole binary V404 CygComments: 6 pages, 2 figures, accepted to A&ASubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
During the June 2015 outburst of the black hole binary V404 Cyg, rapid changes in the X-ray brightness and spectra were common. The INTEGRAL monitoring campaign detected spectacular Eddington-limited X-ray flares, but also rapid variations at much lower flux levels. On 2015 June 21 at 20 h 50 min, the 3-10 keV JEM-X data as well as simultaneous optical data started to display a gradual brightening from one of these low-flux states. This was followed 15 min later by an order-of-magnitude increase of flux in the 20-40 keV IBIS/ISGRI light curve in just 15 s. The best-fitting model for both the pre- and post-transition spectra required a Compton-thick partially covering absorber. The absorber parameters remained constant, but the spectral slope varied significantly during the event, with the photon index decreasing from $\Gamma \approx 3.7$ to $\Gamma \approx 2.3$. We propose that the rapid 20-40 keV flux increase was either caused by a spectral state transition that was hidden from our direct view, or that there was a sudden reduction in the amount of Compton down-scattering of the primary X-ray emission in the disk outflow.
- [84] arXiv:2001.07508 [pdf, other]
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Title: Working Group Report on the Combined Analysis of Muon Density Measurements from Eight Air Shower ExperimentsAuthors: Lorenzo Cazon (for the EAS-MSU, IceCube, KASCADE-Grande, NEVOD-DECOR, Pierre Auger, SUGAR, Telescope Array, and Yakutsk EAS Array collaborations)Comments: 36th International Cosmic Ray Conference, ICRC2019, Madison, USA 2019Journal-ref: PoS(ICRC2019)214Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics - Experiment (hep-ex)
We present a meta-analysis of recent muon density measurements made by eight air shower experiments which cover shower energies ranging from PeV to tens of EeV regarding the muon puzzle in extensive air showers. Some experimental analyses reported deviations between recorded and simulated muon densities in extensive air showers, and others reported no discrepancies. Comparisons between experiments were made using a universal reference scale based on the relative difference to simulated proton and iron initiated air showers. We have applied a cross-calibration of energy scales between experiments based on the isotropic flux of cosmic rays as a reference. Above 10 PeV, most experimental data show a muon excess with respect to simulated air showers, including those performed with the recent post-LHC high-energy interaction models. The discrepancy increases with the shower energy with a slope 8 sigma away from the predictions by EPOS-LHC and QGSJet-II.04. The effect of measurements being made at different zenith angles and energy threshold of muons across different experiments will be addressed.
- [85] arXiv:2001.07510 [pdf, other]
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Title: The Diffuse Supernova Neutrino BackgroundJournal-ref: Research Notes of the AAS, Volume 4, Issue 1, article id. 4 (2020)Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)
The Diffuse Supernova Neutrino Background (DSNB) in the MeV regime represents the cumulative cosmic neutrino emission, predominantly due to core collapse supernovae. We estimate the DSNB flux for different Star Formation Rate Density (SFRD) models. We find that the DSNB flux estimated using the SFRD derived from Fermi-LAT Collaboration et al. (2018) is significantly higher ($\approx$ 32$\%$) relative to the flux estimated using the SFRD from Madau & Fragos (2017). This depicts the sensitivity between the DSNB flux and the SFRD estimates which shows that future detection of the DSNB can be used as a valuable tool to constrain the SFRD.
- [86] arXiv:2001.07516 [pdf, other]
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Title: The H IX galaxy survey III: The gas-phase metallicity in HI eXtreme galaxiesAuthors: K. A. Lutz (1 and 2), V. Kilborn (2), B. Catinella (3 and 4), L. Cortese (3 and 4), T. H. Brown (2 and 5), B. Koribalski (6) ((1) Université de Strasbourg, CNRS, CDS, Observatoire astronomique de Strasbourg, (2) Centre for Astrophysics and Supercomputing, Swinburne University of Technology, (3) International Centre for Radio Astronomy Research (ICRAR), M468, The University of Western Australia, (4) Australian Research Council, Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D), (5) Department of Physics and Astronomy, McMaster University (6) Australia Telescope National Facility, CSIRO Astronomy and Space Science)Comments: Main body: 10 pages, 6 figures; Appendix: 11 pages; Accepted by A&ASubjects: Astrophysics of Galaxies (astro-ph.GA)
This paper presents the analysis of optical integral field spectra for the HI eXtreme (HIX) galaxy sample. HIX galaxies host at least 2.5 times more atomic gas (HI) than expected from their optical R-band luminosity. Previous examination of their star formation activity and HI kinematics suggested that these galaxies stabilise their large HI discs (radii up to 94 kpc) against star formation due to their higher than average baryonic specific angular momentum. A comparison to semi-analytic models further showed that the elevated baryonic specific angular momentum is inherited from the high spin of the dark matter host. In this paper we now turn to the gas-phase metallicity as well as stellar and ionised gas kinematics in HIX galaxies to gain insights into recent accretion of metal-poor gas or recent mergers. We compared the stellar, ionised, and atomic gas kinematics, and examine the variation in the gas-phase metallicity throughout the stellar disc of HIX galaxies. We find no indication for counter-rotation in any of the components, the central metallicities tend to be lower than average, but as low as expected for galaxies of similar HI mass. Metallicity gradients are comparable to other less HI-rich, local star forming galaxies. We conclude that HIX galaxies show no conclusive evidence for recent major accretion or merger events. Their overall lower metallicities are likely due to being hosted by high spin halos, which slows down their evolution and thus the enrichment of their interstellar medium.
- [87] arXiv:2001.07536 [pdf, other]
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Title: Resolving the $H_0$ tension with diffusionSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Theory (hep-th)
The tension between the value of the Hubble constant $H_0$ determined from local supernovae data and the one inferred from the cosmic microwave background based on the $\Lambda$CDM cosmological model may indicate the need for new physics. Here, we show that this `Hubble tension' can be resolved in models involving an effective energy flux from the matter sector into dark energy resulting naturally from a combination of unimodular gravity and an energy diffusion process. The scheme is one where dark energy has the standard equation of state $w=-1$. This proposal provides an alternative phenomenological paradigm accounting for the observations, while offering a general framework to study diffusion effects coming from novel fundamental physical processes.
- [88] arXiv:2001.07548 [pdf, other]
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Title: Particle acceleration with anomalous pitch angle scattering in 3D separator reconnectionComments: 18 pages, 10 figures, accepted to Astronomy & AstrophysicsSubjects: Solar and Stellar Astrophysics (astro-ph.SR); Plasma Physics (physics.plasm-ph); Space Physics (physics.space-ph)
Understanding how the release of stored magnetic energy contributes to the generation of non-thermal high energy particles during solar flares is an important open problem in solar physics. Magnetic reconnection plays a fundamental role in the energy release and conversion processes taking place during flares. A common approach for investigating particle acceleration is to use test particles in fields derived from magnetohydrodynamic (MHD) simulations of reconnection. These MHD simulations use anomalous resistivities that are much larger than the Spitzer resistivity based on Coulomb collisions. The processes leading to enhanced resistivity should also affect the test particles. We explore the link between resistivity and particle orbits building on a previous study using a 2D MHD simulation of magnetic reconnection. This paper extends the previous investigation to a 3D magnetic reconnection configuration and to study the effect on test particle orbits. We carried out orbit calculations using a 3D MHD simulation of separator reconnection. We use the relativistic guiding centre approximation including stochastic pitch angle scattering. The effects of varying the resistivity and the models for pitch angle scattering on particle orbit trajectories, final positions, energy spectra, final pitch angle distribution, and orbit duration are all studied in detail. Pitch angle scattering widens collimated beams of orbit trajectories, allowing orbits to access previously unaccessible field lines; this causes final positions to spread to topological structures that were previously inaccessible. Scattered orbit energy spectra are found to be predominantly affected by the level of anomalous resistivity, with the pitch angle scattering model only playing a role in isolated cases. Scattering is found to play a crucial role in determining the pitch angle and orbit duration distributions.
- [89] arXiv:2001.07550 [pdf, other]
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Title: 13C17O suggests gravitational instability in the HL Tau discComments: Accepted 2020 January 21. Received 2020 January 21; in original form 2019 November 27Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Earth and Planetary Astrophysics (astro-ph.EP); Astrophysics of Galaxies (astro-ph.GA)
We present the first detection of the 13C17O J=3-2 transition toward the HL Tau protoplanetary disc. We find significantly more gas mass (at least a factor of ten higher) than has been previously reported using C18O emission. This brings the observed total disc mass to 0.2 M, which we consider to be a conservative lower limit. Our analysis of the Toomre Q profile suggests that this brings the disc into the regime of gravitational instability. The radial region of instability (50-110 au) coincides with the location of a proposed planet-carved gap in the dust disc and a spiral in the gas. We, therefore, propose that if the origin of the gap is confirmed to be due to a forming giant planet, then it is likely to have formed via the gravitational fragmentation of the protoplanetary disc.
- [90] arXiv:2001.07579 [pdf, other]
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Title: Long-term orbital dynamics of trans-Neptunian objectsAuthors: Melaine SaillenfestComments: 50 pages, 16 figures, 1 table. Accepted for publication in Celestial Mechanics and Dynamical Astronomy, special issue about trans-Neptunian objectsSubjects: Earth and Planetary Astrophysics (astro-ph.EP)
This article reviews the different mechanisms affecting the orbits of trans-Neptunian objects, ranging from internal perturbations (planetary scattering, mean-motion resonances, secular effects) to external perturbations (galactic tides, passing stars). We outline the theoretical tools that can be used to model and study them, focussing on analytical approaches. We eventually compare these mechanisms to the observed distinct populations of trans-Neptunian objects and conclude on how they participate to the sculpting of the whole distribution.
- [91] arXiv:2001.07581 [pdf, ps, other]
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Title: Impact of a companion and of chromospheric emission on the shape of chromosome maps for globular clustersAuthors: Fabrice Martins (1), Julien Morin (1), Corinne Charbonnel (2,3), Carmela Lardo (4), William Chantereau (5) ((1) LUPM, CNRS & Montpellier University, (2) Geneva Observatory, University of Geneva, (3), IRAP, (4) EPFL, (5) Liverpool John Moores University)Comments: 11 pages, 10 figures. Accepted in Astronomy & AstrophysicsSubjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA)
We investigate the role of binaries and chromospheric emission on HST photometry of globular clusters' stars. We quantify their respective effects on the position of stars in the chromosome map, especially among the first population. We computed atmosphere models and synthetic spectra for stars of different chemical compositions, based on isochrones produced by stellar evolution calculations with abundance variations representative of first and second populations in GCs. From this we built synthetic chromosome maps for a mixture of stars of different chemical compositions. We subsequently replaced a fraction of stars with binaries, or stars with chromospheric emission, using synthetic spectroscopy. We studied how the position of stars is affected in the chromosome map. Binaries can, in principle, explain the extension of the first population in the chromosome map. However, we find that given the binary fraction reported for GCs, the density of stars in the extended part is too small. Another difficulty of the binary explanation is that the shape of the distribution of the first population in the chromosome map is different in clusters with similar binary fractions. Additionally, we find that the contribution of chromospheric emission lines to the HST photometry is too small to have an observable impact on the shape of the chromosome map. Continuum chromospheric emission has an effect qualitatively similar to binaries. We conclude that binaries do have an impact on the morphology of the chromosome map of GCs, but they are unlikely to explain entirely the shape of the extended distribution of the first population stars. Uncertainties in the properties of continuum chromospheric emission of stars in GCs prevent any quantitative conclusion. Therefore, the origin of the extended first population remains unexplained.
- [92] arXiv:2001.07596 [pdf, other]
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Title: The LASCO Coronal Brightness IndexComments: 35 pages, 9 Figures. Accepted to Solar PhysicsSubjects: Solar and Stellar Astrophysics (astro-ph.SR)
We present the construction of a new white-light coronal brightness index (CBI) from the entire archive of observations recorded by the Large Angle Spectrometric Coronagraph (LASCO) C2 camera between 1996 and 2017, comprising two full solar cycles. We reduce all fully calibrated daily C2 observations of the white light corona into a single daily coronal brightness observation for every day of observation recorded by the instrument, with mean daily brightness values binned into 0.1 Rsun radial x 1 degree angular regions from 2.4 -- 6.2 Rsun for a full 360-degrees. As a demonstration of the utility of the CBI, we construct a new solar irradiance proxy that correlates well with a variety of direct solar irradiance observations, with correlations shown to be in the range of 0.77-0.89. We also present a correlation mapping technique to show how irradiance correlations depend on, and relate to, coronal structure/locations, and to demonstrate how the LASCO CBI can be used to perform long-term "spatial correlation" studies to investigate relationships between the solar corona and any arbitrary concurrent geophysical index. Using this technique we find possible relationships between coronal brightness and plasma temperature, interplanetary magnetic field magnitude and (very weakly) proton density.
- [93] arXiv:2001.07602 [pdf, other]
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Title: The contribution of nearby supernova remnants on the cosmic ray flux at EarthJournal-ref: Monthly Notices of the Royal Astronomical Society, Manuscript: staa171,2020Subjects: Astrophysics of Galaxies (astro-ph.GA); High Energy Astrophysical Phenomena (astro-ph.HE)
We consider anisotropic diffusion of Galactic cosmic rays in the Galactic magnetic field, using the Jansson-Farrar model for the field. In this paper we investigate the influence of source position on the cosmic ray flux at Earth in two ways: [1] by considering the contribution from cosmic ray sources located in different intervals in Galacto-centric radius, and [2] by considering the contribution from a number of specific and individual close-by supernova remnants. Our calculation is performed by using a fully three-dimensional stochastic method. This method is based on the numerical solution of a set of stochastic differential equations, equivalent to Ito formulation, that describes the propagation of the Galactic cosmic rays.
- [94] arXiv:2001.07611 [pdf, other]
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Title: Effects of neighbouring planets on the formation of resonant dust rings in the inner Solar SystemSubjects: Earth and Planetary Astrophysics (astro-ph.EP)
Context. Findings by the Helios and STEREO mission have indicated the presence of a resonant circumsolar ring of dust associated with Venus. Attempts to model this phenomenon as an analogue to the resonant ring of Earth - as a result of migrating dust trapped in external mean-motion resonances (MMRs) - have so far been unable to reproduce the observed dust feature. Other theories of origin have recently been put forward. However, the reason for the low trapping efficiency of Venus's external MMRs remains unclear. Aims. Here we look into the nature of the dust trapping resonant phenomena that arise from the multi-planet configuration of the inner Solar System, aiming to add to the existent understanding of resonant dust rings in single planet systems. Methods. We numerically modelled resonant dust features associated with the inner planets and specifically looked into the dependency of these structures and the trapping efficiency of particular resonances on the configuration of planets. Results. Besides Mercury showing no resonant interaction with the migrating dust cloud, we find Venus, Earth, and Mars to considerably interfere with each other's resonances, influencing their ability to form circumsolar rings. We find that the single most important reason for the weakness of Venus's external MMR ring is the perturbing influence of its outer neighbour - Earth. In addition, we find Mercury and Mars to produce crescent-shaped density features, caused by a directed apsidal precession occurring in particles traversing their orbital region.
- [95] arXiv:2001.07619 [pdf, other]
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Title: Gravity in the infrared and effective nonlocal modelsComments: 84 pages, 22 figuresSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Theory (hep-th)
We provide a systematic and updated discussion of a research line carried out by our group over the last few years, in which gravity is modified at cosmological distances by the introduction of nonlocal terms, assumed to emerge at an effective level from the infrared behavior of the quantum theory. The requirement of producing a viable cosmology turns out to be very stringent and basically selects a unique model, in which the nonlocal term describes an effective mass for the conformal mode. We discuss how such a specific structure could emerge from a fundamental local theory of gravity, and we perform a detailed comparison of this model with the most recent cosmological datasets, confirming that it fits current data at the same level as $\Lambda$CDM.
Most notably, the model has striking predictions in the sector of tensor perturbations, leading to a very large effect in the propagation of gravitational wave (GWs) over cosmological distances. At the redshifts relevant for the next generation of GW detectors such as Einstein Telescope, Cosmic Explorer and LISA, this leads to deviations from GR that could be as large as $80\%$, and could be verified with the detection of just a single coalescing binary with electromagnetic counterpart. This would also have potentially important consequences for the search of the counterpart since, for a given luminosity distance to the source, as inferred through the GW signal, the actual source redshift could be significantly different from that predicted by $\Lambda$CDM. At the redshifts relevant for advanced LIGO/Virgo/Kagra the effect is smaller, but still potentially observable over a few years of runs at target sensitivity. - [96] arXiv:2001.07633 [pdf, other]
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Title: The signature of primordial black holes in the dark matter halos of galaxiesAuthors: M. R. S. HawkinsComments: 15 pages, 8 figures, published in A&AJournal-ref: A&A, 633, A107, (2020)Subjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
The aim of this paper is to investigate the claim that stars in the lensing galaxy of a gravitationally lensed quasar system can always account for the observed microlensing of the individual quasar images. A small sample of gravitationally lensed quasar systems was chosen where the quasar images appear to lie on the fringe of the stellar distribution of the lensing galaxy. As with most quasar systems, all the individual quasar images were observed to be microlensed. The surface brightness of the lensing galaxy at the positions of the quasar images was measured from HST frames, and converted to stellar surface mass density. The surface density of smoothly distributed dark matter at the image positions was obtained from lensing models of the quasar systems and applied to the stellar surface mass density to give the optical depth to microlensing. This was then used to assess the probability that the stars in the lensing galaxy could be responsible for the observed microlensing. The results were supported by microlensing simulations of the star fields around the quasar images combined with values of convergence and shear from the lensing models. Taken together, the probability that all the observed microlensing is due to stars was found to be ~0.0003. Errors resulting from surface brightness measurement, mass-to-light ratio and the contribution of the dark matter halo do not significantly affect this result. It is argued that the most plausible candidates for the microlenses are primordial black holes, either in the dark matter halos of the lensing galaxies, or more generally distributed along the lines of sight to the quasars.
- [97] arXiv:2001.07651 [pdf, other]
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Title: Progenitors of early-time interacting supernovaeComments: Submitted for publication to MNRAS. 31 pages, 25 figuresSubjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA)
We compute an extensive set of early-time spectra of supernovae interacting with circumstellar material using the radiative transfer code CMFGEN. Our models are applicable to events observed from 1 to a few days after explosion. Using these models, we constrain the progenitor and explosion properties of a sample of 17 observed interacting supernovae at early-times. Because massive stars have strong mass loss, these spectra provide valuable information about supernova progenitors, such as mass-loss rates, wind velocities, and surface abundances. We show that these events span a wide range of explosion and progenitor properties, exhibiting supernova luminosities in the 1e8 to 1e12 Lsun range, temperatures from 10000 to 60000 K, progenitor mass-loss rates from a few 1e-4 up to 1 Msun/yr, wind velocities from 100 to 800 km/s, and surface abundances from solar-like to H-depleted. Our results suggest that many progenitors of supernovae interacting with circumstellar material have significantly increased mass-loss before explosion compared to what massive stars show during the rest of their lifetimes. We also infer a lack of correlation between surface abundances and mass-loss rates. This may point to the pre-explosion mass-loss mechanism being independent of stellar mass. We find that the majority of these events have CNO-processed surface abundances. In the single star scenario this points to a preference towards high-mass RSGs as progenitors of interacting SNe, while binary evolution could impact this conclusion. Our models are publicly available and readily applicable to analyze results from ongoing and future large scale surveys such as the Zwicky Transient Factory.
- [98] arXiv:2001.07659 [pdf, other]
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Title: Discovery of a Sirius-like binary system with a very strongly magnetic white dwarf. Binarity among magnetic white dwarfsComments: Accepted by A&A LettersSubjects: Solar and Stellar Astrophysics (astro-ph.SR)
Binary systems containing a magnetic white dwarf and a main-sequence star are considered extremely rare, perhaps non-existent. In the course of a search of magnetic fields in high-mass white dwarfs we have discovered a Sirius-like wide binary system composed of a main-sequence G0 star and a $M\sim 1.1\,M_\odot$ white dwarf with a huge (hundreds of MG) magnetic field. This star, WDS J03038+0608B, shows a circular polarisation amplitude of 5% in the continuum, with no evidence of variability in a 1d time-scale, little or no linear polarisation in the blue part of the spectrum, and about 2% linear polarisation in the red part of the optical spectrum. A search in the literature reveals the existence of at least four more binary systems that include a magnetic white dwarf and a non-degenerate companion - three such systems passed unremarked in previous studies. We estimate that up to a few percent of magnetic white dwarfs may be found to occur in wide binary pairs. However, at least four of the five known binary systems with a magnetic white dwarf are too widely separated to be expected to evolve into systems experiencing Roche lobe overflow, and cannot be considered as progenitors of magnetic cataclysmic variable (AM Her and DQ Her) systems.
- [99] arXiv:2001.07663 [pdf, other]
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Title: X-ray spectra and polarization from magnetar candidatesComments: Accepted for publication in MNRAS. 18 pages, 16 figures, 4 tablesSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
Magnetars are believed to host the strongest magnetic fields in the present universe ($B\gtrsim10^{14}$ G) and the study of their persistent emission in the X-ray band offers an unprecendented opportunity to gain insight into physical processes in the presence of ultra-strong magnetic fields. Up to now, most of our knowledge about magnetar sources came from spectral analysis, which allowed to test the resonant Compton scattering scenario and to probe the structure of the star magnetosphere. On the other hand, radiation emitted from magnetar surface is expected to be strongly polarized and its observed polarization pattern bears the imprint of both scatterings onto magnetospheric charges and QED effects as it propagates in the magnetized vacuum around the star. X-ray polarimeters scheduled to fly in the next years will finally allow to exploit the wealth of information stored in the polarization observables. Here we revisit the problem of assessing the spectro-polarimetric properties of magnetar persistent emission. At variance with previous investigations, proper account for more physical surface emission models is made by considering either a condensed surface or a magnetized atmosphere. Results are used to simulate polarimetric observations with the forthcoming Imaging X-ray Polarimetry Explorer (IXPE). We find that X-ray polarimetry will allow to detect QED vacuum effects for all the emission models we considered and to discriminate among them.
- [100] arXiv:2001.07665 [pdf, other]
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Title: Extracting high-level information from gamma-ray burst supernova spectraComments: Accepted for publication in MNRASSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
Radiation transport codes are often used in astrophysics to construct spectral models. In this work we demonstrate how producing these models for a time series of data can provide unique information about supernovae (SNe). Unlike previous work, we specifically concentrate on the method for obtaining the best synthetic spectral fits, and the errors associated with the preferred model parameters. We demonstrate how varying the ejecta mass, bolometric luminosity ($L_{bol}$) and photospheric velocity ($v_{ph}$), affects the outcome of the synthetic spectra. As an example we analyses the photospheric phase spectra of the GRB-SN\,2016jca. It is found that for most epochs (where the afterglow subtraction is small) the error on $L_{bol}$ and $v_{ph}$ was $\sim$5\%. The uncertainty on ejecta mass and K.E. was found to be $\sim$20%, although this can be expected to dramatically decrease if models of nebular phase data can be simultaneously produced. We also demonstrate how varying the elemental abundance in the ejecta can produce better synthetic spectral fits. In the case of SN\,2016jca it is found that a decreasing $^{56}$Ni abundance as a function of decreasing velocity produces the best fit models. This could be the case if the $^{56}$Ni was sythesised at the side of the GRB jet, or dredged up from the centre of the explosion. The work presented here can be used as a guideline for future studies on supernovae which use the same or similar radiation transfer code.
- [101] arXiv:2001.07667 [pdf, other]
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Title: Confirmation of WASP-107b's extended Helium atmosphere with Keck II/NIRSPECComments: Accepted for publication in The Astronomical Journal. 12 pages, 7 figures, 2 tablesSubjects: Earth and Planetary Astrophysics (astro-ph.EP)
We present the detection of helium in the extended atmosphere of the sub-Saturn WASP-107b using high resolution ($R \approx 25000$) near-infrared spectra from Keck II/NIRSPEC. We find peak excess absorption of $7.26 \pm 0.24\%$ (30$\sigma$) centered on the HeI triplet at 10833A. The amplitude and shape of the helium absorption profile is in excellent agreement with previous observations of escaping helium from this planet made by CARMENES and HST. This suggests there is no significant temporal variation in the signature of escaping helium from the planet over a two year baseline. This result demonstrates Keck II/NIRSPEC's ability to detect atmospheric escape in exoplanets, making it a useful instrument to further our understanding of the evaporation of exoplanetary atmospheres via ground-based observations of HeI.
- [102] arXiv:2001.07684 [pdf, other]
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Title: Stellar metallicities from SkyMapper photometry I: A study of the Tucana II ultra-faint dwarf galaxyComments: 24 pages; 12 figures, 4 tables; Accepted for publication in ApJSubjects: Astrophysics of Galaxies (astro-ph.GA)
We present a study of the ultra-faint Milky Way dwarf satellite galaxy Tucana II using deep photometry from the 1.3m SkyMapper telescope at Siding Spring Observatory, Australia. The SkyMapper filter-set contains a metallicity-sensitive intermediate-band $v$ filter covering the prominent Ca II K feature at 3933.7A. When combined with photometry from the SkyMapper $u, g$, and $i$ filters, we demonstrate that $v$ band photometry can be used to obtain stellar metallicities with a precision of $\sim0.20$dex when [Fe/H] $> -2.5$, and $\sim0.34$dex when [Fe/H] $< -2.5$. Since the $u$ and $v$ filters bracket the Balmer Jump at 3646A, we also find that the filter-set can be used to derive surface gravities. We thus derive photometric metallicities and surface gravities for all stars down to a magnitude of $g\sim20$ within $\sim$75 arcminutes of Tucana II. Photometric metallicity and surface gravity cuts remove nearly all foreground contamination. By incorporating Gaia proper motions, we derive quantitative membership probabilities which recover all known members on the red giant branch of Tucana II. Additionally, we identify multiple likely new members in the center of the system and candidate members several half-light radii from the center of the system. Finally, we present a metallicity distribution function derived from the photometric metallicities of likely Tucana II members. This result demonstrates the utility of wide-field imaging with the SkyMapper filter-set in studying UFDs, and in general, low surface brightness populations of metal-poor stars. Upcoming work will clarify the membership status of several distant stars identified as candidate members of Tucana II.
- [103] arXiv:2001.07691 [pdf, other]
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Title: Identifying New X-ray Binary Candidates in M31 using Random Forest ClassificationComments: 16 pages, 8 figures; accepted to MNRASSubjects: Astrophysics of Galaxies (astro-ph.GA); High Energy Astrophysical Phenomena (astro-ph.HE); Instrumentation and Methods for Astrophysics (astro-ph.IM)
Identifying X-ray binary (XRB) candidates in nearby galaxies requires distinguishing them from possible contaminants including foreground stars and background active galactic nuclei. This work investigates the use of supervised machine learning algorithms to identify high-probability X-ray binary candidates. Using a catalogue of 943 Chandra X-ray sources in the Andromeda galaxy, we trained and tested several classification algorithms using the X-ray properties of 163 sources with previously known types. Amongst the algorithms tested, we find that random forest classifiers give the best performance and work better in a binary classification (XRB/non-XRB) context compared to the use of multiple classes. Evaluating our method by comparing with classifications from visible-light and hard X-ray observations as part of the Panchromatic Hubble Andromeda Treasury, we find compatibility at the 90% level, although we caution that the number of sources in common is rather small. The estimated probability that an object is an X-ray binary agrees well between the random forest binary and multiclass approaches and we find that the classifications with the highest confidence are in the X-ray binary class. The most discriminating X-ray bands for classification are the 1.7-2.8, 0.5-1.0, 2.0-4.0, and 2.0-7.0 keV photon flux ratios. Of the 780 unclassified sources in the Andromeda catalogue, we identify 16 new high-probability X-ray binary candidates and tabulate their properties for follow-up.
- [104] arXiv:2001.07700 [pdf, other]
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Title: Fundamental Plane of BOSS galaxies: Correlations with galaxy properties, density field and impact on RSD measurementsComments: 28 pages, 17+ figures. Main results in Fig. 2, 3, 4, 8, 13, 17. Submitted to MNRASSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Astrophysics of Galaxies (astro-ph.GA)
Fundamental plane of elliptical galaxies can be used to predict the intrinsic size of galaxies and has a number of plausible application to study cosmology and galaxy physics. We present a detailed analysis of the fundamental plane of the SDSS-III BOSS LOWZ and CMASS galaxies. For the standard fundamental plane, we find a strong redshift evolution for the mean residual and show that it is primarily driven by the redshift evolution of the surface brightness of the galaxies. After correcting for the redshift evolution, the FP residuals are strongly correlated with the galaxy properties and some observational systematics. We show that the variations in the FP between the central and satellite galaxies, that have been observed in the literature, can primarily be explained by the correlation of the FP with the galaxy luminosity. We also measure the cross correlations of the FP residuals with the galaxy density field. The amplitude of the cross correlations depends on the galaxy properties and environment with brighter and redder galaxies showing stronger correlation. In general, galaxies in denser environments (higher galaxy bias ) show stronger correlations. We also compare FP amplitude with the amplitudes of intrinsic alignments of galaxy shapes (IA), finding the two to be correlated. Finally, using the FP residuals we also study the impact of intrinsic alignments on the constraint of growth rate using redshift space distortions. We do not observe any significant trends in measurements of the growth rate $f$ as function of the amplitude of FP-density correlations, resulting in null detection of the effects of IA on the RSD measurements.
Cross-lists for Wed, 22 Jan 20
- [105] arXiv:1911.02427 (cross-list from physics.ins-det) [pdf, other]
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Title: KLASH Conceptual Design ReportAuthors: D. Alesini, D. Babusci, P. Beltrame S.J., F. Björkeroth, F. Bossi, P. Ciambrone, G. Delle Monache, D. Di Gioacchino, P. Falferi, A. Gallo, C. Gatti, A. Ghigo, M. Giannotti, G. Lamanna, C. Ligi, G. Maccarrone, A. Mirizzi, D. Montanino, D. Moricciani, A. Mostacci, M. Mück, E. Nardi, F. Nguyen, L. Pellegrino, A. Rettaroli, R. Ricci, L. Sabbatini, S. Tocci, L. VisinelliSubjects: Instrumentation and Detectors (physics.ins-det); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Experiment (hep-ex); High Energy Physics - Phenomenology (hep-ph)
The last decade witnessed an increasing interest in axions and axion-like particles with many theoretical works published and many new experimental proposals that started a real race towards their discovery. This paper is the Conceptual Design Report of the KLASH (KLoe magnet for Axion SearcH) experiment at the Laboratori Nazionali di Frascati (LNF). The idea of this experiment has been stimulated by the availability of the large volume superconducting magnet, with a moderate magnetic field of 0.6 T, used in the KLOE detector at the DAFNE collider. The main conclusion we draw from this report is the possibility to build and put in operation at LNF in 2-3 years a large haloscope with the sensitivity to KSVZ axions in the low mass range between 0.2 and 1 $\mu$eV, complementary to that of other experiments. Timeline and cost are competitive with respect to other proposals in the same mass region thanks to the availability of most of the infrastructure, in particular the superconducting magnet and the cryogenics plant.
- [106] arXiv:2001.06490 (cross-list from gr-qc) [pdf, other]
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Title: A trend in the effective spin distribution of LIGO binary black holes with massComments: 10 pages, 7 figures, submitted as a revision to ApJ main journalSubjects: General Relativity and Quantum Cosmology (gr-qc); High Energy Astrophysical Phenomena (astro-ph.HE)
Binary black holes (BBHs) detected by gravitational wave (GW) observations could be broadly divided into two formation channels: those formed through field binary evolution and those assembled dynamically in dense stellar systems. Each of these formation channels, and their sub-channels, populate a distinct region in the effective spin-mass ($\chi_{\rm eff}-M$) plane. Depending on the branching ratio of different channels, an ensemble of BBHs could show a trend in this plane. Here we fit a mass-dependent distribution for $\chi_{\rm eff}$ to the GWTC-1 BBHs from the first and second observing runs of Advanced LIGO and Advanced Virgo. We find a negative correlation between mass and the mean effective spin ($\bar{\chi}_{\mathrm{eff}}$), and positive correlation with its dispersion ($\sigma_{\chi_\mathrm{eff}}$) at 75\% and 80\% confidence. This trend is robust against the choice of mass variable, but most pronounced when the mass variable is taken to be the chirp mass of the binary. The result is consistent with significant contributions from both dynamically assembled and field binaries in the GWTC-1 catalog. The upcoming LIGO O3a data release will critically test this interpretation.
- [107] arXiv:2001.06518 (cross-list from hep-th) [pdf, other]
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Title: Large Field Excursions from Dimensional (De)constructionComments: 1+27 pagesSubjects: High Energy Physics - Theory (hep-th); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
An inflation model based on dimensional (de)construction of a massive gauge theory is proposed. The inflaton in this model is the "zero-mode" of a component of the massive gauge field in the (de)constructed extra dimensions. The inflaton potential originates from the gauge invariant Stueckelberg potential. At low energy, the field range of the inflaton is enhanced by a factor $N^{\frac{d}{2}}$ compared to the field range of the original fields in the model, where $d$ is the number of the (de)constructed extra dimensions and $N$ is the number of the lattice points in each (de)constructed dimension. This enhancement of the field range is used to achieve a trans-Planckian inflaton field excursion. The extension of the mechanism ``excursions through KK modes'' to the case of (de)constructed extra dimensions is also studied. The burst of particle productions by this mechanism may have observable consequences in a region of the model parameter space.
- [108] arXiv:2001.06581 (cross-list from gr-qc) [pdf, ps, other]
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Title: Constraint on the radius of five-dimensional dS spacetime with GW170817 and GRB 170817AComments: 11 pages, 2 figuresSubjects: General Relativity and Quantum Cosmology (gr-qc); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics - Theory (hep-th)
The recent detections of the gravitational wave (GW) event GW170817 and its electromagnetic counterpart GRB 170817A produced by a binary neutron star (NS) merger is a new milestone of multi-messenger astronomy. The time interval between these two signals has attracted widespread attention from physicists. In the braneworld scenario, GWs could propagate through the bulk while electromagnetic waves (EMWs) are bounded on the brane, i.e., our Universe. Therefore, the trajectories of GWs and EMWs may follow different pathes. If GWs and EMWs are originated simultaneously from the same source on the brane, they are expected to arrive at the observer successively. Consequently, the time delay between GW170817 and GRB 170817A may carry the information of the extra dimension. In this paper, we try to investigate the phenomenon in the context of a five-dimensional dS ($\text{dS}_5$) spacetime. We assume two special models for our Universe, i.e., the de Sitter model and the Einstein-de Sitter model, and compare the gravitation horizon radius and photon horizon radius in each case. Our results show that the $\text{dS}_5$ radius will contribute to the time delay in the latter case. With the data of the observation, we constrain the $\text{dS}_5$ radius to $\ell\gtrsim7.5\times10^{2}\,\text{Tpc}$. After considering the uncertainty in the source redshift and the time-lags given by different astrophysical processes of the binary NS merger, we find that our constraint is not sensitive to the redshift in the range of (0.005, 0.01) and the time-lag in the range of (-100 s, 1.734 s).
- [109] arXiv:2001.06695 (cross-list from gr-qc) [pdf, ps, other]
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Title: Gravitational Tensor and Acoustic Waves in A Radiation Dominated Universe: Weyl Curvature and Polarization PatternsComments: 29 pagesSubjects: General Relativity and Quantum Cosmology (gr-qc); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Theory (hep-th)
We provide evidence that gravitational radiation in a 4D radiation-dominated universe, with equation-of-state $w=1/3$, consists of two components: helicity-2 gravitons and massless scalar acoustic waves. On physical grounds, we would expect the homogeneous solution of the Weyl tensor components to be a good approximation to its inhomogeneous counterparts, whenever the observer is located well in the far zone of an isolated astrophysical source of cosmological gravitational radiation. We show explicitly that these homogeneous and inhomogeneous solutions both receive contributions from the gauge-invariant tensor {\it and} the two Bardeen (acoustic) scalars. Comparison of these Weyl tensor computations thus allows us to not only identify, in the high frequency limit, the corresponding gravitational tensor and scalar radiation; but also their oscillatory polarization patterns.
- [110] arXiv:2001.06830 (cross-list from gr-qc) [pdf, ps, other]
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Title: Geometric Inflation and Dark Energy with Axion $F(R)$ GravityComments: PRD AcceptedSubjects: General Relativity and Quantum Cosmology (gr-qc); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Theory (hep-th)
We present a model of $F(R)$ gravity in the presence of a string theory motivated misalignment axion like particle materialized in terms of a canonical scalar field minimally coupled with gravity, and we study the cosmological phenomenology of the model, emphasizing mainly on the late-time era. The main result of the paper is that inflation and the dark energy era may be realized in a geometric way by an $F(R)$ gravity, while the axion is the dark matter constituent of the Universe. The $F(R)$ gravity model consists of an $R^2$ term, which as we show dominates the evolution during the early time, thus producing a viable inflationary phenomenology, and a power law term $\sim R^{\delta}$ with $\delta\ll 1 $ and positive, which eventually controls the late-time era. The axion field remains frozen during the inflationary era, which is an effect known for misalignment axions, but as the Universe expands, the axion starts to oscillate, and its energy density scales eventually as we show, as $\rho_a\sim a^{-3}$. After appropriately rewriting the gravitational equations in terms of the redshift $z$, we study in detail the late-time phenomenology of the model, and we compare the results with the $\Lambda$CDM model and the latest Planck 2018 data. As we show, the model for small redshifts $0<z<5$ is phenomenologically similar to the $\Lambda$CDM model, however at large redshifts and deeply in the matter domination era, the results are different from those of the $\Lambda$CDM model due to the dark energy oscillations. For the late-time study we investigate the behavior of several well-known statefinder quantities, like the deceleration parameter, the jerk and $Om(z)$, and we demonstrate that the statefinders which contain lower derivatives of the Hubble rate have similar behavior for both the $\Lambda$CDM and the axion $F(R)$ gravity model.
- [111] arXiv:2001.07009 (cross-list from physics.ao-ph) [pdf, other]
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Title: Global climate modeling of Saturn's atmosphere. Part IV: stratospheric equatorial oscillationAuthors: Deborah Bardet, Aymeric Spiga, Sandrine Guerlet, Simon Cabanes, Ehouarn Millour, Alexandre BoissinotComments: 57 pages, 22 figures, submitted to Icarus (under review)Subjects: Atmospheric and Oceanic Physics (physics.ao-ph); Earth and Planetary Astrophysics (astro-ph.EP)
The Composite InfraRed Spectrometer (CIRS) on board Cassini revealed an equatorial oscillation of stratospheric temperature, reminiscent of the Earth's Quasi-Biennial Oscillation (QBO), as well as anomalously high temperatures under Saturn's rings. To better understand these predominant features of Saturn's atmospheric circulation in the stratosphere, we have extended towards higher altitudes the DYNAMICO-Saturn global climate model (GCM), already used in a previous publication to study the tropospheric dynamics, jets formation and planetary-scale waves activity. Firstly, we study the higher model top impact on the tropospheric zonal jets and kinetic energy distribution. Raising the model top prevents energy and enstrophy accumulation at tropopause levels. The reference GCM simulation with 1/2$^{\circ}$ latitude/longitude resolution and a raised model top exhibits a QBO-like oscillation produced by resolved planetary-scale waves. However, the period is more irregular and the downward propagation faster than observations. Furthermore, compared to the CIRS observation retrievals, the modeled QBO-like oscillation underestimates by half both the amplitude of temperature anomalies at the equator and the vertical characteristic length of this equatorial oscillation. This QBO-like oscillation is mainly driven by westward-propagating waves; a significant lack of eastward wave-forcing explains a fluctuating eastward phase of the QBO-like oscillation. At 20$^{\circ}$N and 20$^{\circ}$S latitudes, the DYNAMICO-Saturn GCM exhibits several strong seasonal eastward jets, alternatively in the northern and southern hemisphere. These jets are correlated with the rings' shadowing. Using a GCM simulation without rings' shadowing, we show its impact on Saturn's stratospheric dynamics. Both residual-mean circulation and eddy forcing are impacted by rings' shadowing.
- [112] arXiv:2001.07087 (cross-list from nucl-ex) [pdf, ps, other]
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Title: Measurement and analysis of nuclear $γ$-ray production cross sections in proton interactions with Mg, Si and Fe nuclei abundant in astrophysical sites over the incident energy range $E=30-66$ MeVAuthors: W. Yahia-Cherif, S. Ouichaoui, J. Kiener, E.A. Lawrie, J.J. Lawrie, V. Tatischeff, A. Belhout, D. Moussa, P. Papka, H. Benhabiles, T.D. Bucher, A. Chafa, J.L. Conradie, S. Damache, M. Debabi, I. Deloncle, J.L. Easton, C. Hamadache, F. Hammache, P. Jones, B.V. Kheswa, N.A. Khumalo, T. Lamula, S.N.T. Majola, J. Ndayishimye, D. Negi, S.P. Noncolela, N. de Séréville, J.F. Sharpey-Schafer, O. Shirinda, M. Wiedeking, S. WyngaardtComments: 22 pages, 10 figures, five tables; regular article submitted to Phys Rev CSubjects: Nuclear Experiment (nucl-ex); Solar and Stellar Astrophysics (astro-ph.SR)
Gamma-ray production cross section excitation functions have been measured for $30$, $42$, $54$ and $66$ MeV proton beams accelerated onto targets of astrophysical interest, $^{nat}$C, C + O (Mylar), $^{nat}$Mg, $^{nat}$Si and $^{56}$Fe, at the Sector Separated Cyclotron (SSC) of iThemba LABS (near Cape Town, South Africa). The AFRODITE array equipped with 8 Compton suppressed HPGe clover detectors was used to record $\gamma$-ray data. For known, intense $\gamma$-ray lines the previously reported experimental data measured up to $E_{p}\simeq$ $25$ MeV at the Washington and Orsay tandem accelerators were extended to higher proton energies. Our experimental data for the last 3 targets are reported here and discussed with respect to previous data and the Murphy \textit{et al.} compilation [ApJS 183, 142 (2009)], as well as to predictions of the nuclear reaction code TALYS. The overall agreement between theory and experiment obtained in first-approach calculations using default input parameters of TALYS has been appreciably improved by using modified optical model potential (OMP), deformation, and level density parameters. The OMP parameters have been extracted from theoretical fits to available experimental elastic/inelastic nucleon scattering angular distribution data by means of the coupled-channels reaction code OPTMAN. Experimental data for several new $\gamma$-ray lines are also reported and discussed. The astrophysical implications of our results are emphasised.
- [113] arXiv:2001.07172 (cross-list from physics.space-ph) [pdf, ps, other]
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Title: Dependence of ion temperatures on alpha-proton differential flow vector and heating mechanisms in the solar windComments: 21 pages, 5 figures, accepted for publication in ApJ LettersSubjects: Space Physics (physics.space-ph); Solar and Stellar Astrophysics (astro-ph.SR)
According to \emph{Wind} observations between June 2004 and May 2019, this Letter investigates the proton and alpha particle temperatures in the space of ($\theta_d$, $V_d/V_A$) for the first time, where $\theta_d$ and $V_d$ are the radial angle and magnitude of alpha$-$proton differential flow vector respectively, $V_A$ is the local Alfv\'en speed. Results show that the temperatures significantly depend on $\theta_d$ as well as $V_d/V_A$. In case of low proton parallel beta ($\beta_{p{\parallel}} < 1$), it is found that the proton perpendicular temperature is clearly enhanced when $\theta_d$ is small ($\lesssim 45^\circ$) and $V_d/V_A \gtrsim 0.5$. On the contrary, the perpendicular temperature of alpha particles is considerably enhanced when $\theta_d$ is large ($\gtrsim 90^\circ$) or $V_d/V_A$ is sufficiently small. The maximum of proton parallel temperature takes place at $\theta_d \sim 90^\circ$ accompanied by higher $\beta_{p{\parallel}}$ and by larger turbulence amplitude of magnetic fluctuations in inertial range. This study should present strong evidence for cyclotron resonance heating of protons and alpha particles in the solar wind. Other mechanisms including Landau resonance and stochastic heating are also proposed, which tend to have different ($\theta_d$, $V_d/V_A$) spaces than cyclotron resonance heating.
- [114] arXiv:2001.07240 (cross-list from hep-ex) [pdf, other]
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Title: Search for multi-messenger signals in NOvA coincident with LIGO/Virgo detectionsAuthors: NOvA Collaboration: M. A. Acero (2), P. Adamson (12), L. Aliaga (12), T. Alion (40), V. Allakhverdian (27), N. Anfimov (27), A. Antoshkin (27), L. Asquith (40), A. Aurisano (6), A. Back (24), C. Backhouse (45), M. Baird (20 and 40 and 46), N. Balashov (27), P. Baldi (25), B. A. Bambah (17), S. Bashar (44), K. Bays (4 and 19), S. Bending (45), R. Bernstein (12), V. Bhatnagar (33), B. Bhuyan (14), J. Bian (25 and 31), J. Blair (16), A. C. Booth (40), P. Bour (9), C. Bromberg (29), N. Buchanan (8), A. Butkevich (22), S. Calvez (8), T. J. Carroll (43 and 49), E. Catano-Mur (24 and 48), S. Childress (12), B. C. Choudhary (11), T. E. Coan (38), M. Colo (48), L. Corwin (37), L. Cremonesi (45), G. S. Davies (32 and 20), P. F. Derwent (12), R. Dharmapalan (1), P. Ding (12), Z. Djurcic (1), D. Doyle (8), et al. (136 additional authors not shown)Comments: 11 pages, 6 figuresSubjects: High Energy Physics - Experiment (hep-ex); High Energy Astrophysical Phenomena (astro-ph.HE)
Using the NOvA neutrino detectors, a broad search has been performed for any signal coincident with 28 gravitational wave events detected by the LIGO/Virgo Collaboration between September 2015 and July 2019. For all of these events, NOvA is sensitive to possible arrival of neutrinos and cosmic rays of GeV and higher energies. For five (seven) events in the NOvA Far (Near) Detector, timely public alerts from the LIGO/Virgo Collaboration allowed recording of MeV-scale events. No signal candidates were found.
- [115] arXiv:2001.07552 (cross-list from hep-th) [pdf, other]
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Title: Exact solutions of domain wall junctions in arbitrary dimensionsComments: 33 pages, 10 figuresSubjects: High Energy Physics - Theory (hep-th); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Phenomenology (hep-ph)
Exact analytic solutions of static, stable, non-planar BPS domain wall junctions are obtained in extended Abelian-Higgs models in $(D+1)$-dimensional spacetime. For specific choice of mass parameters, the Lagrangian is invariant under the symmetric group ${\cal S}_{D+1}$ of degree $D+1$ spontaneously broken down to ${\cal S}_D$ in vacua, admitting ${\cal S}_{D+1}/{\cal S}_D$ domain wall junctions. In $D=2$, there are three vacua and three domain walls meeting at a junction point, in which the conventional topological charges $Y$ and $Z$ exist for the BPS domain wall junctions and the BPS domain walls, respectively as known before. In $D=3$, there are four vacua, six domain walls, four junction lines on which three domain walls meet, and one junction point on which all the six domain walls meet. We define a new topological charge $X$ for the junction point in addition to the conventional topological charges $Y$ and $Z$. In general dimensions, we find that the configuration expressed in the $D$-dimensional real space is dual to a regular $D$-simplex in the $D$-dimensional internal space and that a $d$-dimensional subsimplex of the regular $D$-simplex corresponds to a $(D-d)$-dimensional intersection. Topological charges are generalized to the level-$d$ wall charge $W_d$ for the $d$-dimensional subsimplexes.
- [116] arXiv:2001.07637 (cross-list from hep-ph) [pdf, other]
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Title: Gravitational waves from neutrino mass and dark matter genesisComments: 6 pages, 3 figures, 1 tableSubjects: High Energy Physics - Phenomenology (hep-ph); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Experiment (hep-ex); High Energy Physics - Theory (hep-th)
We introduce a model in which the genesis of dark matter and neutrino masses is associated with a first order phase transition of a scalar singlet field. During the phase transition a source right-handed neutrino acquires a spacetime-dependent mass dynamically, a small fraction of which is converted via resonant oscillations into a very weakly mixed dark right-handed neutrino with the observed dark matter relic abundance. Neutrino masses are generated via a traditional two right-handed neutrino type-I seesaw between a third right-handed neutrino and the source neutrino. The gravitational waves produced during the phase transition have a peak frequency that increases with the dark matter mass, and are detectable at future gravitational wave interferometers for dark matter masses in the 1 MeV - 20 GeV range. For source right-handed neutrinos heavier than a GeV, successful leptogenesis is also possible.
Replacements for Wed, 22 Jan 20
- [117] arXiv:1801.01494 (replaced) [pdf, ps, other]
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Title: Coincident SZ and $γ$-ray signals from cluster virial shocksComments: Minor changes in presentationSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Astrophysical Phenomena (astro-ph.HE)
- [118] arXiv:1811.06499 (replaced) [pdf, other]
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Title: Cosmological constraints from galaxy-lensing cross correlations using BOSS galaxies with SDSS and CMB lensingComments: Published in MNRASSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
- [119] arXiv:1812.08754 (replaced) [pdf, other]
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Title: Higgs-$R^2$ inflation -- full slow-roll study at tree-levelComments: v2. Added references, corrected numerical analysis of inflationary trajectories. Range of values for the spectral index narrowed down. v3. Added references and clarified text, fixed typos. Published version. 18 pages, 5 figuresJournal-ref: JCAP01(2020)041Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Phenomenology (hep-ph)
- [120] arXiv:1902.00037 (replaced) [pdf, other]
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Title: Signatures of Bimodality in Nebular Phase Type Ia Supernova SpectraComments: 12 pages, 4 tables, 6 figures. Accepted for publication in MNRASSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
- [121] arXiv:1902.04550 (replaced) [pdf, other]
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Title: A nontrivial footprint of standard cosmology in the future observations of low-frequency gravitational wavesComments: 19 pages, 7 figures, 3 tables. Initially submitted to ApJ on March 5, 2019Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc)
- [122] arXiv:1902.09343 (replaced) [pdf, other]
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Title: Some new hints on cosmic-ray propagation from AMS-02 nuclei spectraComments: 11 pages, 5 figures, and 2 tables. Discussions added. JCAP versionJournal-ref: JCAP01(2020)036Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics - Phenomenology (hep-ph)
- [123] arXiv:1902.10475 (replaced) [pdf, other]
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Title: Searching for Axino-Like Particle at Fixed Target ExperimentsComments: 10 pages, 7 figures, Published in Physics of the Dark UniverseJournal-ref: Physics of the Dark Universe, Volume 27, January 2020, 100460Subjects: High Energy Physics - Phenomenology (hep-ph); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
- [124] arXiv:1905.02205 (replaced) [pdf, other]
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Title: The Most Rapidly Declining Type I Supernova 2019bkc/ATLAS19dqrAuthors: Ping Chen, Subo Dong, M. D. Stritzinger, Simon Holmbo, Jay Strader, C. S. Kochanek, Eric W. Peng, S. Benetti, D. Bersier, Sasha Brownsberger, David A. H. Buckley, Mariusz Gromadzki, Shane Moran, A. Pastorello, Elias Aydi, Subhash Bose, Thomas Connor, N. Elias-Rosa, K. Decker French, Thomas W.-S. Holoien, Seppo Mattila, B. J. Shappee, Antony A. Stark, Samuel J. SwihartComments: Match the version published by ApJLJournal-ref: ApJL 889 L6 (2020)Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR)
- [125] arXiv:1905.03512 (replaced) [pdf, other]
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Title: Constraints on Flavor-Diagonal Non-Standard Neutrino Interactions from Borexino Phase-IIAuthors: S. K. Agarwalla, M. Agostini, K. Altenmüller, S. Appel, V. Atroshchenko, Z. Bagdasarian, D. Basilico, G. Bellini, J. Benziger, D. Bick, G. Bonfini, D. Bravo, B. Caccianiga, F. Calaprice, A. Caminata, L. Cappelli, P. Cavalcante, F. Cavanna, A. Chepurnov, K. Choi, D. D'Angelo, S. Davini, A. Derbin, A. Di Giacinto, V. Di Marcello, X.F. Ding, A. Di Ludovico, L. Di Noto, I. Drachnev, K. Fomenko, A. Formozov, D. Franco, F. Gabriele, C. Galbiati, M. Gschwender, C. Ghiano, M. Giammarchi, A. Goretti, M. Gromov, D. Guffanti, C. Hagner, E. Hungerford, Aldo Ianni, Andrea Ianni, A. Jany, D. Jeschke, S. Kumaran, V. Kobychev, G. Korga, T. Lachenmaier, M. Laubenstein, E. Litvinovich, P. Lombardi, L. Ludhova, G. Lukyanchenko, L. Lukyanchenko, I. Machulin, G. Manuzio, S. Marcocci, J. Maricic, J. Martyn, et al. (45 additional authors not shown)Comments: 28 pages, 7 figures. Slight modifications in the title, abstract, and conclusion. Few references added. Text expanded for clarity. Accepted in JHEPSubjects: High Energy Physics - Phenomenology (hep-ph); Solar and Stellar Astrophysics (astro-ph.SR); High Energy Physics - Experiment (hep-ex); Instrumentation and Detectors (physics.ins-det)
- [126] arXiv:1905.07100 (replaced) [pdf, other]
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Title: A strategy to search for an inner binary black hole from the motion of the tertiary starComments: 20 pages, 10 figures, 5 tables Substantially revised and now accepted for publication in ApJSubjects: Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR); General Relativity and Quantum Cosmology (gr-qc)
- [127] arXiv:1905.07378 (replaced) [pdf, other]
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Title: Black hole shadow with a cosmological constant for cosmological observersComments: 8 pages, 2 figures, a few typos in table numbers and text correctedSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc)
- [128] arXiv:1905.08540 (replaced) [pdf, other]
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Title: Confirmation of the Stellar Binary Microlensing Event, Macho 97-BLG-28Authors: Joshua W. Blackman, Jean-Philippe Beaulieu, Andrew A. Cole, Aikaterini Vandorou, Naoki Koshimoto, Etienne Bachelet, Aparna Bhattacharya, David BennettComments: 9 pages, 5 figuresSubjects: Solar and Stellar Astrophysics (astro-ph.SR); Earth and Planetary Astrophysics (astro-ph.EP)
- [129] arXiv:1906.00866 (replaced) [pdf, other]
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Title: Wide-band Rotation Measure SynthesisComments: 17 Pages, 13 Figures. Accepted to ApJSubjects: Instrumentation and Methods for Astrophysics (astro-ph.IM)
- [130] arXiv:1906.06641 (replaced) [pdf, other]
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Title: Fitting formulae for evolution tracks of massive stars under extreme metal poor environments for population synthesis calculations and star cluster simulationsComments: 15 pages, 11 figures, 5 tablesSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR)
- [131] arXiv:1906.10302 (replaced) [pdf, other]
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Title: Rapid Particle Acceleration due to Recollimation Shocks and Turbulent Magnetic Fields in Injected Jets with Helical Magnetic FieldsAuthors: Kenichi Nishikawa, Yosuke Mizuno, Jose L. Gomez, Ioana Dutan, Jacek Niemiec, Oleh Kobzar, Nicholas MacDonald, Athina Meli, Martin Pohl, Kouichi HirotaniComments: 8 pages, 5 figures, submitted to ApJL, movie will be added if possible (dBtotByz11MF_011.mp4 5.8MB), significantly revised with corrected figures. After rejected by ApJL, submitted to MNRAS, revised, 8 pages, 6 figuresSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
- [132] arXiv:1907.03897 (replaced) [pdf, other]
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Title: Future Prospects for Probing Scalar-Tensor Theories with Gravitational Waves from Mixed BinariesComments: 8 pages, 8 figures; updated to match with the version published in CQGSubjects: General Relativity and Quantum Cosmology (gr-qc); High Energy Astrophysical Phenomena (astro-ph.HE)
- [133] arXiv:1907.05899 (replaced) [pdf, other]
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Title: X-ray Plateaus in Gamma Ray Bursts' light-curves from jets viewed slightly off-axisComments: 11 pages, 6 figures. Accepted for publication in MNRASSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
- [134] arXiv:1907.13375 (replaced) [pdf, ps, other]
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Title: Effects of the equation of state on the bulk properties of maximally-rotating neutron starsComments: v1: 16 pages, 24 figures. v2: 18 pages, 14 labeled figures, 5 tables, sections and references had been updated, accepted for publication in Phys. Rev. CSubjects: Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc)
- [135] arXiv:1908.00587 (replaced) [pdf, other]
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Title: nsCouette -- A high-performance code for direct numerical simulations of turbulent Taylor-Couette flowAuthors: Jose Manuel Lopez, Daniel Feldmann, Markus Rampp, Alberto Vela-Martin, Liang Shi, Marc AvilaComments: ~3000 words, 3 figures (in colour)Journal-ref: SoftwareX, Volume 11, 100395, 2020Subjects: Fluid Dynamics (physics.flu-dyn); Solar and Stellar Astrophysics (astro-ph.SR); Chaotic Dynamics (nlin.CD); Atmospheric and Oceanic Physics (physics.ao-ph)
- [136] arXiv:1908.02201 (replaced) [pdf, other]
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Title: Clouds of Fluffy Aggregates: How They Form in Exoplanetary Atmospheres and Influence Transmission SpectraComments: 23 pages, 12 figures, accepted for publication in ApJ. v3: Figures 5-9 have been correctedSubjects: Earth and Planetary Astrophysics (astro-ph.EP)
- [137] arXiv:1908.03084 (replaced) [pdf, other]
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Title: On the impact of magnetic-field models in galaxy clusters on constraints on axion-like paricles from the lack of irregularities in high-energy spectra of astrophysical sourcesComments: 8 pages, 4 figures, elsarticle.sty. V2: extended explanations, corrected figures (including the would-be exclusion plot) - conclusions unchanged. Version accepted by Phys. Lett. BSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics - Phenomenology (hep-ph)
- [138] arXiv:1908.08580 (replaced) [pdf, other]
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Title: The long-lived Type IIn SN 2015da: Infrared echoes and strong interaction within an extended massive shellAuthors: L. Tartaglia, A. Pastorello, J. Sollerman, C. Fransson, S. Mattila, M. Fraser, F. Taddia, L. Tomasella, M. Turatto, A. Morales-Garoffolo, N. Elias-Rosa, P. Lundqvist, J. Harmanen, T. Reynolds, E. Cappellaro, C. Barbarino, A. Nyholm, E. Kool, E. Ofek, X. Gao, Z. Jin, H. Tan, D. J. Sand, F. Ciabattari, X. Wang, J. Zhang, F. Huang, W. Li, J. Mo, L. Rui, D. Xiang, T. Zhang, G. Hosseinzadeh, D. A. Howell, C. McCully, S. Valenti, S. Benetti, E. Callis, A. S. Carracedo, C. Fremling, T. Kangas, A. Rubin, A. Somero, G. TerreranComments: 23 pages (19+appendix), 15 figures, 11 tables (Tables A.1-A.4 at CDS only). Accepted for publication on Astronomy and AstrophysicsSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
- [139] arXiv:1908.10590 (replaced) [pdf, other]
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Title: Cosmological parameter estimation from large-scale structure deep learningAuthors: Shuyang Pan, Miaoxin Liu, Jaime Forero-Romero, Cristiano G. Sabiu, Zhigang Li, Haitao Miao, Xiao-Dong LiComments: 16 pages, 10 figuresSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc)
- [140] arXiv:1908.11418 (replaced) [pdf, other]
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Title: kiloHertz gravitational waves from binary neutron star remnants: time-domain model and constraints on extreme matterAuthors: Matteo Breschi, Sebastiano Bernuzzi, Francesco Zappa, Michalis Agathos, Albino Perego, David Radice, Alessandro NagarJournal-ref: Phys. Rev. D 100, 104029 (2019)Subjects: General Relativity and Quantum Cosmology (gr-qc); High Energy Astrophysical Phenomena (astro-ph.HE)
- [141] arXiv:1908.11508 (replaced) [pdf, other]
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Title: Quantifying the accuracy of the Alcock-Paczynski scaling of baryon acoustic oscillation measurementsComments: 42 pages, 8 figures, 2 tables; v2: Small corrections, matches published versionJournal-ref: JCAP 01 (2020) 038Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc)
- [142] arXiv:1909.01305 (replaced) [pdf, other]
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Title: Microwave multiplexing on the Keck ArrayAuthors: Ari Cukierman, Zeeshan Ahmed, Shawn Henderson, Edward Young, Cyndia Yu, Denis Barkats, David Brown, Saptarshi Chaudhuri, James Cornelison, John M. D'Ewart, Marion Dierickx, Bradley J. Dober, John Dusatko, Sofia Fatigoni, Jeff P. Filippini, Josef C. Frisch, Gunther Haller, Mark Halpern, Gene C. Hilton, Johannes Hubmayr, Kent D. Irwin, Kirit S. Karkare, Ethan Karpel, Sarah A. Kernasovskiy, John M. Kovac, Attila Kovacs, Stephen E. Kuenstner, Chao-Lin Kuo, Dale Li, John A. B. Mates, Stephen Smith, Tyler St. Germaine, Joel N. Ullom, Leila R. Vale, Daniel D. Van Winkle, Jesus Vasquez, Justin Willmert, Lingzhen Zeng, P. A. R. Ade, M. Amiri, R. Basu Thakur, C. A. Bischoff, J. J. Bock, H. Boenish, E. Bullock, V. Buza, J. Cheshire, J. Connors, M. Crumrine, L. Duband, G. Hall, S. Harrison, S. R. Hildebrandt, et al. (32 additional authors not shown)Comments: 9 pages, 11 figures, Accepted by the Journal of Low Temperature Physics (Proceedings of the 18th International Workshop on Low Temperature Detectors)Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM)
- [143] arXiv:1909.02615 (replaced) [pdf, other]
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Title: Game of cones: A nulling strategy for modelling lensing convergence in cones with large deviation theoryComments: 23 pages, accepted to MNRAS, comments welcomeSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
- [144] arXiv:1909.07395 (replaced) [pdf, other]
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Title: Cusp-to-core transition in low-mass dwarf galaxies induced by dynamical heating of cold dark matter by primordial black holesAuthors: Pierre Boldrini, Yohei Miki, Alexander Y. Wagner, Roya Mohayaee, Joseph Silk, Alexandre ArbeyComments: 8 pages, 7 figures, Accepted by MNRASSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Astrophysics of Galaxies (astro-ph.GA)
- [145] arXiv:1909.09179 (replaced) [pdf, other]
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Title: Kelvin-Helmholtz versus Tearing Instability: What Drives Turbulence in Stochastic Reconnection?Comments: 20 pages, 8 figuresSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); Astrophysics of Galaxies (astro-ph.GA); Solar and Stellar Astrophysics (astro-ph.SR); Plasma Physics (physics.plasm-ph); Space Physics (physics.space-ph)
- [146] arXiv:1909.09672 (replaced) [pdf, other]
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Title: Re-evaluating evidence for Hawking points in the CMBSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
- [147] arXiv:1909.11683 (replaced) [pdf, other]
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Title: Terrestrial and Martian Heat Flow Limits on Dark MatterComments: 20 pages, 18 figures, PRD versionSubjects: High Energy Physics - Phenomenology (hep-ph); Earth and Planetary Astrophysics (astro-ph.EP); High Energy Physics - Experiment (hep-ex)
- [148] arXiv:1910.02038 (replaced) [pdf, other]
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Title: Calibration and Performance of the NIKA2 camera at the IRAM 30-meter TelescopeAuthors: L. Perotto, N. Ponthieu, J.-F. Macías-Pérez, R. Adam, P. Ade, P. André, A. Andrianasolo, H. Aussel, A. Beelen, A. Benoît, S. Berta, A. Bideaud, O. Bourrion, M. Calvo, A. Catalano, B. Comis, M. De Petris, F.-X. Désert, S. Doyle, E. F. C. Driessen, P. García, A. Gomez, J. Goupy, D. John, F. Kéruzoré, C. Kramer, B. Ladjelate, G. Lagache, S. Leclercq, J.-F. Lestrade, A. Maury, P. Mauskopf, F. Mayet, A. Monfardini, S. Navarro, J. Peñalver, F. Pierfederici, G. Pisano, V. Revéret, A. Ritacco, C. Romero, H. Roussel, F. Ruppin, K. Schuster, S. Shu, A. Sievers, C. Tucker, R. ZylkaComments: 37 pages, accepted for publication in A&ASubjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Instrumentation and Detectors (physics.ins-det)
- [149] arXiv:1910.04793 (replaced) [pdf, other]
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Title: Improved constraints from ultra-faint dwarf galaxies on primordial black holes as dark matterSubjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
- [150] arXiv:1910.05228 (replaced) [pdf, other]
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Title: Assessment of the Systematic Uncertainties in the Cosmological Analysis of the SDSS Supernovae Photometric SampleSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
- [151] arXiv:1910.05336 (replaced) [pdf, other]
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Title: KiDS+VIKING-450 and DES-Y1 combined: Mitigating baryon feedback uncertainty with COSEBIsAuthors: Marika Asgari, Tilman Tröster, Catherine Heymans, Hendrik Hildebrandt, Jan Luca van den Busch, Angus H. Wright, Ami Choi, Thomas Erben, Benjamin Joachimi, Shahab Joudaki, Arun Kannawadi, Konrad Kuijken, Chieh-An Lin, Peter Schneider, Joe ZuntzComments: Accepted for publication in A&A. 15 pages, 7 figuresSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
- [152] arXiv:1911.00014 (replaced) [pdf, other]
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Title: From Hydrogen to Helium: The Spectral Evolution of White Dwarfs as Evidence for Convective MixingAuthors: Tim Cunningham, Pier-Emmanuel Tremblay, Nicola Pietro Gentile Fusillo, Mark Hollands, Elena CukanovaiteComments: 14 pages, 13 figures, accepted for publication in MNRASSubjects: Solar and Stellar Astrophysics (astro-ph.SR)
- [153] arXiv:1911.01418 (replaced) [pdf, ps, other]
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Title: Physics Beyond The Standard Model with Circular Polarization in the CMB and CMB-21cm Cross-CorrelationComments: 29 pages. v2: matches published versionJournal-ref: JCAP 2001 (2020) no.01, 032Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Phenomenology (hep-ph); High Energy Physics - Theory (hep-th)
- [154] arXiv:1911.03484 (replaced) [pdf, other]
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Title: Hubble-induced phase transitions: Walls are not foreverComments: 18 pages, 8 figures, minor revision matches published versionSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Phenomenology (hep-ph)
- [155] arXiv:1911.06461 (replaced) [pdf, other]
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Title: Perturbation theory for the redshift-space matter power spectra after reconstructionComments: 15 pages, 3 figures, accepted for publications in PRDSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
- [156] arXiv:1911.10542 (replaced) [pdf, other]
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Title: The running curvatonComments: 22 pages, 3 figures, comments are welcomeSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Phenomenology (hep-ph); High Energy Physics - Theory (hep-th)
- [157] arXiv:1911.12685 (replaced) [pdf, other]
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Title: Primordial black hole merger rates: distributions for multiple LIGO observablesComments: 23 pages + appendices, 17 figures; v2: Minor changes, clarification of probabilities in table 1 supersedes published versionJournal-ref: JCAP01(2020)031Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc)
- [158] arXiv:1912.00110 (replaced) [pdf, other]
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Title: Detection of the 511 keV Galactic positron annihilation line with COSIAuthors: Carolyn A. Kierans, Steven E. Boggs, Andreas Zoglauer, Alex W. Lowell, Clio C. Sleator, Jacqueline Beechert, Terri J. Brandt, Pierre Jean, Hadar Lazar, Jarred M. Roberts, Thomas Siegert, John A. Tomsick, Peter von BallmoosComments: 14 pages, 12 figures. Submitted to ApJSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
- [159] arXiv:1912.00860 (replaced) [pdf, other]
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Title: Characterization of Transition Edge Sensors for the Simons ObservatoryAuthors: Jason R. Stevens, Nicholas F. Cothard, Eve M. Vavagiakis, Aamir Ali, Kam Arnold, Jason E. Austermann, Steve K. Choi, Bradley J. Dober, Cody Duell, Shannon M. Duff, Gene C. Hilton, Shuay-Pwu Patty Ho, Thuong D. Hoang, Johannes Hubmayr, Adrian T. Lee, Aashrita Mangu, Federico Nati, Michael D. Niemack, Christopher Raum, Mario Renzullo, Maria Salatino, Trevor Sasse, Sara M. Simon, Suzanne Staggs, Aritoki Suzuki, Patrick Truitt, Joel Ullom, John Vivalda, Michael R. Vissers, Samantha Walker, Benjamin Westbrook, Edward J. Wollack, Zhilei Xu, Daniel YohannesComments: 9 Pages, 5 figures, Low Temperature Detectors 19Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM)
- [160] arXiv:1912.01911 (replaced) [pdf, other]
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Title: Global Site Selection for AstronomyComments: 19 Pages, 4 Figures, 7 tables, Accepted for publication in MNRASSubjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Earth and Planetary Astrophysics (astro-ph.EP)
- [161] arXiv:1912.03794 (replaced) [pdf, other]
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Title: The Young Planet DS Tuc Ab has a Low ObliquityAuthors: Benjamin T. Montet, Adina D. Feinstein, Rodrigo Luger, Megan E. Bedell, Michael A. Gully-Santiago, Johanna K. Teske, Sharon Xuesong Wang, R. Paul Butler, Erin Flowers, Stephen A. Shectman, Jeffrey D. Crane, Ian B. ThompsonComments: 18 pages, four figures, AJ acceptedSubjects: Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)
- [162] arXiv:1912.04903 (replaced) [pdf, ps, other]
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Title: Early-type Host Galaxies of Type Ia Supernovae. II. Evidence for Luminosity Evolution in Supernova CosmologyComments: To be published in 20 January 2020 issue of ApJ; see Figure 16 for the luminosity evolution mimicking dark energySubjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
- [163] arXiv:1912.06577 (replaced) [pdf, other]
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Title: The spectral evolution of disc dominated tidal disruption eventsComments: 20 pages, 19 figures. Accepted for publication in MNRAS. Comments welcomeSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
- [164] arXiv:1912.06662 (replaced) [pdf, other]
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Title: Properties of simulated galaxies and supermassive black holes in cosmic voidsAuthors: Melanie Habouzit, Alice Pisani, Andy Goulding, Yohan Dubois, Rachel S. Somerville, Jenny E. GreeneComments: accepted by MNRAS without modification, 24 pages, 17 figuresSubjects: Astrophysics of Galaxies (astro-ph.GA)
- [165] arXiv:1912.06970 (replaced) [pdf, other]
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Title: Generalized Lomb-Scargle analysis of $\rm{^{36}Cl}$ decay rate measurements at PTB and BNLComments: 7 pages, 4 figuresSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); Instrumentation and Methods for Astrophysics (astro-ph.IM); Nuclear Experiment (nucl-ex)
- [166] arXiv:1912.07608 (replaced) [pdf, other]
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Title: Type Ia supernovae from non-accreting progenitorsComments: accepted in Astronomy & Astrophysics; v2 matches the accepted version. Comments are welcomeSubjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA)
- [167] arXiv:1912.07677 (replaced) [pdf, other]
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Title: MAVKA: Program Of Statistically Optimal Determination Of Phenomenological Parameters Of Extrema. Parabolic Spline Algorithm and Analysis of Variability of the Semi-Regular Star Z UMaComments: Journal of Physical Studies, 2020, v. 24 (Paper in Ukrainian)Subjects: Solar and Stellar Astrophysics (astro-ph.SR)
- [168] arXiv:1912.08231 (replaced) [pdf, other]
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Title: Magnetically charged black holes from non-linear electrodynamics and the Event Horizon TelescopeComments: 28 pages, 9 figures, 4 tables, accepted for publication in JCAPSubjects: General Relativity and Quantum Cosmology (gr-qc); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics - Theory (hep-th)
- [169] arXiv:1912.09809 (replaced) [pdf, other]
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Title: Twin stars and the stiffness of the nuclear equation of state: ruling out strong phase transitions below $1.7n_0$ with the new NICER radius measurementsComments: 7 pages, 6 figuresSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
- [170] arXiv:2001.00049 (replaced) [pdf, other]
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Title: High-resolution Spectra and Biosignatures of Earth-like Planets Transiting White DwarfsComments: 10 pages, 1 table, 4 figures; accepted to ApJLSubjects: Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)
- [171] arXiv:2001.00194 (replaced) [pdf, other]
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Title: EDGES signal in presence of magnetic fieldsComments: 4 pages, 4 figuresSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
- [172] arXiv:2001.02211 (replaced) [pdf, other]
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Title: Spectrophotometric calibration of low-resolution spectraSubjects: Instrumentation and Methods for Astrophysics (astro-ph.IM)
- [173] arXiv:2001.02304 (replaced) [pdf, other]
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Title: Spherical and cylindrical solutions in f (T) gravity by Noether Symmetry ApproachComments: 9 pages, accepted for publication in EPJ CSubjects: General Relativity and Quantum Cosmology (gr-qc); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics - Theory (hep-th)
- [174] arXiv:2001.02689 (replaced) [pdf, other]
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Title: A physically motivated definition for the size of galaxies in an era of ultra-deep imagingComments: 19 pages, 10 figures, MNRAS, in press. Key results of the paper are shown in Figures 2, 3 and 4. Chamba et al. (2020) applies this new size definition to ultra-diffuse galaxies showing that they have sizes of dwarf galaxiesSubjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
- [175] arXiv:2001.02808 (replaced) [pdf, other]
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Title: A Comparison of Flare Forecasting Methods. IV. Evaluating Consecutive-Day Forecasting PatternsAuthors: Sung-Hong Park, K. D. Leka, Kanya Kusano, Jesse Andries, Graham Barnes, Suzy Bingham, D. Shaun Bloomfield, Aoife E. McCloskey, Veronique Delouille, David Falconer, Peter T. Gallagher, Manolis K. Georgoulis, Yuki Kubo, Kangjin Lee, Sangwoo Lee, Vasily Lobzin, JunChul Mun, Sophie A. Murray, Tarek A. M. Hamad Nageem, Rami Qahwaji, Michael Sharpe, Rob A. Steenburgh, Graham Steward, Michael TerkildsenComments: 33 pages, 13 figures, accepted for publication in ApJSubjects: Solar and Stellar Astrophysics (astro-ph.SR)
- [176] arXiv:2001.03134 (replaced) [pdf, ps, other]
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Title: Sensor Distortion Effects in Photon Monte Carlo SimulationsAuthors: J. R. Peterson, P. O'Connor, A. Nomerotski, E. Magnier, J. G. Jernigan, J. Cheng, W. Cui, E. Peng, A. Rasmussen, G. SembroskiComments: Accepted for publication in ApJ; 13 pages, 12 figuresSubjects: Instrumentation and Methods for Astrophysics (astro-ph.IM)
- [177] arXiv:2001.04532 (replaced) [pdf, other]
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Title: The high-energy environment and atmospheric escape of the mini-Neptune K2-18 bAuthors: Leonardo A. dos Santos, David Ehrenreich, Vincent Bourrier, Nicola Astudillo-Defru, Xavier Bonfils, François Forget, Christophe Lovis, Francesco Pepe, Stéphane UdryComments: 5 pages, 4 figures, accepted for publication in A&A Letters, V2 with editorial correctionsSubjects: Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)
- [178] arXiv:2001.04548 (replaced) [pdf, other]
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Title: Tidal Disruption Flares from Stars on Marginally Bound and Unbound OrbitsComments: 37 pages, 11 figures, 2 tables, submitted for publication, comments welcomeSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
- [179] arXiv:2001.04587 (replaced) [pdf, other]
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Title: A Merged Search-Coil and Fluxgate Magnetometer Data Product for Parker Solar Probe FIELDSAuthors: Trevor A. Bowen, Stuart D. Bale, John W. Bonnell, Thierry Dudok de Wit, Keith Goetz, Katherine Goodrich, Jacob Gruesbeck, Peter R. Harvey, Guillaume Jannet, Andriy Koval Robert J. MacDowall, David M. Malaspina, Marc Pulupa, Claire Revillet, David Sheppard, Adam SzaboSubjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Solar and Stellar Astrophysics (astro-ph.SR); Instrumentation and Detectors (physics.ins-det); Space Physics (physics.space-ph)
- [180] arXiv:2001.05392 (replaced) [pdf, ps, other]
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Title: Gravitational radiation by magnetic field: application to millisecond magnetarsComments: 3 figures, v2: presentation improved, Comments welcome!Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc)
- [181] arXiv:2001.05436 (replaced) [pdf, other]
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Title: Limits on the Electromagnetic Counterpart to S190814bvAuthors: Alan M. Watson, Nathaniel R. Butler, William H. Lee, Rosa L. Becerra, Margarita Pereyra, Fernando Angeles, Alejandro Farah, Liliana Figueroa, Diego González-Buitrago, Fernando Quirós, Jaime Ruíz-Díaz-Soto, Carlos Tejada de Vargas, Silvio J. Tinoco, Tanner WolframComments: Accepted by MNRAS. 6 pages. Fixed typos and referencesSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); Instrumentation and Methods for Astrophysics (astro-ph.IM)
- [182] arXiv:2001.05623 (replaced) [pdf, ps, other]
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Title: CO-Line and Radio Continuum Study of Elephant Trunks: The Pillars of Creation in M16Authors: Yoshiaki SofueComments: 15 pages, 16 figures, 2 tables, MNRAS in pressSubjects: Astrophysics of Galaxies (astro-ph.GA)
- [183] arXiv:2001.06239 (replaced) [pdf, other]
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Title: The effects of surface fossil magnetic fields on massive star evolution: II. Implementation of magnetic braking in MESA and implications for the evolution of surface rotation in OB starsAuthors: Z. Keszthelyi, G. Meynet, M.E. Shultz, A. David-Uraz, A. ud-Doula, R.H.D. Townsend, G.A. Wade, C. Georgy, V. Petit, S.P. OwockiComments: accepted for publication in MNRAS, a zenodo record is available at: this https URLSubjects: Solar and Stellar Astrophysics (astro-ph.SR)
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