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New submissions for Wed, 13 Nov 19

[1]  arXiv:1911.04495 [pdf, other]

Title: Formation of Mass Gap Black Holes in Gravitational Wave Merger Events from Wide Hierarchical Quadruple Systems

Authors: Mohammadtaher Safarzadeh, Adrian S. Hamers, Abraham Loeb, Edo Berger

Comments: submitted to ApJL

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)

We investigate secular evolution in hierarchical quadruple systems as a formation channel of mass-gap black holes (with masses of about $3-5$ $M_{\odot}$) in systems that will eventually lead to binary black hole mergers detectable by ground-based gravitational wave detectors (LIGO/Virgo). We show that in a 3+1 hierarchical system, two episodes of induced mergers would first cause two neutron stars to merge and form a mass-gap black hole, which will subsequently merge with another (more massive) black hole through a second induced merger. We demonstrate that such systems are stable to flybys, and their formation would predict a high mass ratio and eccentric merger of a mass-gap black hole with a more massive black hole companion. Such a formation channel may explain observed gravitational wave events such as the recently-discovered LIGO/Virgo events S190814bv and S190924h.

[2]  arXiv:1911.04496 [pdf, other]

Title: Star formation histories of the LEGUS dwarf galaxies (III): the non-bursty nature of 23 star forming dwarf galaxies

Authors: M. Cignoni (1 and 2 and 3), E. Sacchi (4), M. Tosi (3), A. Aloisi (4), D. O. Cook (5 and 6), D. Calzetti (7), J. C. Lee (6), E. Sabbi (4), D. A. Thilker (13), A. Adamo (8), D. A. Dale (9), B. G. Elmegreen (10), J.S. Gallagher III (14), E. K. Grebel (11), K. E. Johnson (15), M. Messa (8), L. J. Smith (12), L. Ubeda (4) ((1) Department of Physics - University of Pisa, Pisa, Italy, (2) INFN, Pisa, Italy, (3) INAF-Osservatorio di Astrofisica e Scienza dello Spazio, Bologna, Italy, (4) STSCI, Baltimore, USA, (5) Department of Physics & Astronomy, California Institute of Technology, Pasadena, USA, (6) IPAC/Caltech, Pasadena, USA, (7) Department of Astronomy, University of Massachusetts, Amherst, USA, (8) Department of Astronomy, The Oskar Klein Centre, Stockholm University, Sweden, (9) Department of Physics and Astronomy, University of Wyoming, USA, (10) IBM Research Division, T.J. Watson Research Center, NY, USA, (11) Astronomisches Rechen-Institut, Zentrum für Astronomie der Universität Heidelberg, Heidelberg, Germany, (12) European Space Agency/Space Telescope Science Institute, Baltimore, USA, (13) Department of Physics and Astronomy, The Johns Hopkins University, Baltimore USA (14) Dept. of Astronomy, University of Wisconsin--Madison, USA, (15) Department of Astronomy, University of Virginia, Charlottesville, USA)

Comments: 29 pages, 19 figures, accepted for publication in ApJ

Subjects: Astrophysics of Galaxies (astro-ph.GA); Instrumentation and Methods for Astrophysics (astro-ph.IM); Solar and Stellar Astrophysics (astro-ph.SR)

We derive the recent star formation histories of 23 active dwarf galaxies using HST observations from the Legacy Extragalactic UV Survey (LEGUS). We apply a color-magnitude diagram fitting technique using two independent sets of stellar models, PARSEC-COLIBRI and MIST. Despite the non-negligible recent activity, none of the 23 star forming dwarfs show enhancements in the last 100 Myr larger than three times the 100-Myr-average. The unweighted mean of the individual SFHs in the last 100 Myr is also consistent with a rather constant activity, irrespective of the atomic gas fraction. We confirm previous results that for dwarf galaxies the CMD-based average star formation rates (SFRs) are generally higher than the FUV-based SFR. For half of the sample, the 60-Myr-average CMD-based SFR is more than two times the FUV SFR. In contrast, we find remarkable agreement between the 10-Myr-average CMD-based SFR and the H${\alpha}$-based SFR. Finally, using core helium burning stars of intermediate mass we study the pattern of star formation spatial progression over the past 60 Myr, and speculate on the possible triggers and connections of the star formation activity with the environment in which these galaxies live. Approximately half of our galaxies show spatial progression of star formation in the last 60 Myr, and/or very recent diffuse and off-center activity compared to RGB stars.

[3]  arXiv:1911.04497 [pdf, other]

Title: Testing Self-Interacting Dark Matter with Galaxy Warps

Authors: Kris Pardo, Harry Desmond, Pedro G. Ferreira

Comments: 12 pages, 5 figures; accepted for publication in PRD

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Astrophysics of Galaxies (astro-ph.GA)

Self-interacting dark matter (SIDM) is an able alternative to collisionless dark matter. If dark matter does have self-interactions, we would expect this to cause a separation between the collisionless stars and the dark matter halo of a galaxy as it falls through a dark matter medium. For stars arranged in a disk, this would generate a U-shaped warp. The magnitude of this warping depends on the SIDM cross section, type of self-interaction, relative velocity of galaxy and background, halo structure, and density of the dark matter medium. In this paper, we set constraints on long-range (light mediator) dark matter self-interaction by means of this signal. We begin by measuring U-shaped warps in 3,213 edge-on disk galaxies within the Sloan Digital Sky Survey. We then forward-model the expected warp from SIDM on a galaxy-by-galaxy basis by combining models of halo structure, density and velocity field reconstructions, and models for the dark matter interactions. We find no evidence for a contribution to the warps from SIDM. Our constraints are highly dependent on the uncertain velocities of our galaxies: we find $\tilde{\sigma}/m_{\rm{DM}} \lesssim 3\times 10^{-13}~\rm{cm}^2/\rm{g}$ at fixed velocity $v = 300~\rm{km/s}$ -- a bound that scales roughly linearly with increasing $v$. We also consider galaxy velocities from the CosmicFlows-3 catalogue. These limits are stronger than those from dwarf galaxy evaporation, and we show that they will scale well with additional data from the next generation of photometric galaxy surveys. Finally, we forecast constraints for contact and intermediate-range interactions that could be achieved with a similar sample of galaxies in cluster environments, where multi-streaming and the fluid approximation are satisfied.

[4]  arXiv:1911.04499 [pdf, other]

Title: Two-year Cosmology Large Angular Scale Surveyor (CLASS) Observations: 40 GHz Telescope Pointing, Beam Profile, Window Function, and Polarization Performance

Authors: Zhilei Xu, Michael K. Brewer, Pedro Fluxa, Yunyang Li, Keisuke Osumi, Bastian Pradenas, Aamir Ali, John W. Appel, Charles L. Bennett, Ricardo Bustos, Manwei Chan, David T. Chuss, Joseph Cleary, Jullianna Couto, Sumit Dahal, Rahul Datta, Kevin Denis, Rolando Dunner, Joseph Eimer, Thomas Essinger-Hileman, Kathleen Harrington, Jeffrey Iuliano, Tobias A. Marriage, Nathan Miller, Carolina Núñez, Ivan L. Padilla, Lucas Parker, Matthew A. Petroff, Rodrigo Reeves, Karwan Rostem, Duncan J. Watts, Janet Weiland, Edward J. Wollack

Comments: 31 pages, 24 figures, submitted to ApJ

Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM)

The Cosmology Large Angular Scale Surveyor (CLASS) is a telescope array that observes the cosmic microwave background (CMB) over 75% of the sky from the Atacama Desert, Chile, at frequency bands centered near 40, 90, 150, and 220 GHz. CLASS measures the large angular scale ($1^\circ\lesssim\theta\leqslant 90^\circ$) CMB polarization to constrain the tensor-to-scalar ratio at the $r\sim0.01$ level and the optical depth to last scattering to the sample variance limit. This paper presents the optical characterization of the 40 GHz telescope during its first observation era, from September 2016 to February 2018. High signal-to-noise observations of the Moon establish the pointing and beam calibration. The telescope boresight pointing variation is $<0.023^\circ$ ($<1.6$% of the beam's full width at half maximum (FWHM)). We estimate beam parameters per detector and in aggregate, as in the CMB survey maps. The aggregate beam has a FWHM of $1.579^\circ\pm.001^\circ$ and a solid angle of $838 \pm 6\ \mu{\rm sr}$, consistent with physical optics simulations. The corresponding beam window function has sub-percent error per multipole at $\ell < 200$. An extended $90^\circ$ beam map reveals no significant far sidelobes. The observed Moon polarization shows that the instrument polarization angles are consistent with the optical model and that the temperature-to-polarization leakage fraction is $<10^{-4}$ (95% C.L.). We find that the Moon-based results are consistent with measurements of M42, RCW 38, and Tau A from CLASS's CMB survey data. In particular, Tau A measurements establish degree-level precision for instrument polarization angles.

[5]  arXiv:1911.04500 [pdf, other]

Title: E0102-VR: exploring the scientific potential of Virtual Reality for observational astrophysics

Authors: E. Baracaglia, F.P.A. Vogt

Comments: 8 pages, 4 figures, 1 table, accepted for publication in Astronomy & Computing. Compiled VR application available at this https URL

Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR)

Virtual Reality (VR) technology has been subject to a rapid democratization in recent years, driven in large by the entertainment industry, and epitomized by the emergence of consumer-grade, plug-and-play, room-scale VR devices. To explore the scientific potential of this technology for the field of observational astrophysics, we have created an experimental VR application: E0102-VR. The specific scientific goal of this application is to facilitate the characterization of the 3D structure of the oxygen-rich ejecta in the young supernova remnant 1E 0102.2-7219 in the Small Magellanic Cloud. Using E0102-VR, we measure the physical size of two large cavities in the system, including a (7.0$\pm$0.5) pc-long funnel structure on the far-side of the remnant. The E0102-VR application, albeit experimental, demonstrates the benefits of using human depth perception for a rapid and accurate characterization of complex 3D structures. Given the implementation costs (time-wise) of a dedicated VR application like E0102-VR, we conclude that the future of VR for scientific purposes in astrophysics most likely resides in the development of a robust, generic application dedicated to the exploration and visualization of 3D observational datasets, akin to a ``ds9-VR''.

[6]  arXiv:1911.04505 [pdf, other]

Title: The Schrödinger-Poisson method for Large-Scale Structure

Authors: Mathias Garny, Thomas Konstandin, Henrique Rubira

Comments: 29 pages, 17 figures

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)

We study the Schr\"odinger-Poisson (SP) method in the context of cosmological large-scale structure formation in an expanding background. In the limit $\hbar \to 0$, the SP technique can be viewed as an effective method to sample the phase space distribution of cold dark matter that remains valid on non-linear scales. We present results for the 2D and 3D matter correlation function and power spectrum at length scales corresponding to the baryon acoustic oscillation (BAO) peak. We discuss systematic effects of the SP method applied to cold dark matter and explore how they depend on the simulation parameters. In particular, we identify a combination of simulation parameters that controls the scale-independent loss of power observed at low redshifts, and discuss the scale relevant to this effect.

[7]  arXiv:1911.04507 [pdf, other]

Title: Probing the galaxy-halo connection with total satellite luminosity

Authors: Jeremy L. Tinker, Junzhi Cao, Mehmet Alpaslan, Joseph DeRose, Yao-Yuan Mao, Risa H. Wechsler

Comments: 21 pages, submitted to MNRAS

Subjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO)

We demonstrate how the total luminosity in satellite galaxies is a powerful probe of dark matter halos around central galaxies. The method cross-correlates central galaxies in spectroscopic galaxy samples with fainter galaxies detected in photometric surveys. After background subtraction, the excess galaxies around the central galaxies represent faint satellite galaxies within the dark matter halo. Using abundance matching models, we show that the the total galaxy luminosity, L_sat, scales linearly with host halo mass, making L_sat an excellent proxy for M_h. L_sat is also sensitive to the formation time of the halo, as younger halos have more substructure at fixed M_h. We demonstrate that probes of galaxy large-scale environment can break this degeneracy. Although this is an indirect probe of the halo, it can yield a high-S/N measurement for galaxies expected to occupy halos at $<10^{12}$ M_sol, where other methods suffer from larger errors. In this paper we focus on observational and theoretical systematics in the L_sat method. We test the robustness of our method of finding central galaxies and our methods of estimating the number of background galaxies. We implement this method on central galaxies in SDSS data, with satellites identified in faint imaging from the DESI Legacy Imaging Surveys. We find excellent agreement between our theoretical predictions and the observational measurements. Finally, we compare our L_sat measurements to weak lensing estimates of M_h for red and blue subsamples. In the stellar mass range where the measurements overlap, we find consistent results, where red galaxies live in larger halos. However, the L_sat approach allows us to probe significantly lower mass galaxies. At these masses, the L_sat values are equivalent. This example shows the potential of L_sat as a probe of dark halos. (Abridged)

[8]  arXiv:1911.04508 [pdf, other]

Title: Order-disorder phase transition in black-hole star clusters. II. A scale-free cluster

Authors: Scott Tremaine

Comments: MNRAS, in press

Subjects: Astrophysics of Galaxies (astro-ph.GA)

The supermassive black holes found at the centers of galaxies are often surrounded by dense star clusters. The ages of these clusters are generally longer than the resonant-relaxation time and shorter than the two-body relaxation time over a wide range of radii. We explore the thermodynamic equilibria of such clusters using a simple self-similar model. We find that the cluster exhibits a phase transition between a high-temperature spherical equilibrium and a low-temperature equilibrium in which the stars are on high-eccentricity orbits with nearly the same orientation. In the absence of relativistic precession, the spherical equilibrium is metastable below the critical temperature and the phase transition is first-order. When relativistic effects are important, the spherical equilibrium is linearly unstable below the critical temperature and the phase transition is continuous. A similar phase transition has recently been found in a model cluster composed of stars with a single semimajor axis. The presence of the same phenomenon in two quite different cluster models suggests that lopsided equilibria may form naturally in a wide variety of black-hole star clusters.

[9]  arXiv:1911.04509 [pdf, other]

Title: Connecting SDSS central galaxies to their host halos using total satellite luminosity

Authors: Mehmet Alpaslan, Jeremy L. Tinker

Comments: 21 pages, 16 figures. To be submitted to MNRAS

Subjects: Astrophysics of Galaxies (astro-ph.GA)

The total luminosity of satellite galaxies around a central galaxy, L$_{sat}$, is a powerful metric for probing dark matter halos. In this paper we use data from the Sloan Digital Sky Survey and DESI Legacy Imaging Surveys to explore the relationship between L$_{sat}$ and various observable galaxy properties for a sample of 117,966 central galaxies out to $z = 0.15$. At fixed stellar mass, every galaxy property we explore shows a correlation with L$_{sat}$. This implies that dark matter halos play a possibly significant role in determining these secondary galaxy properties. We quantify these correlations by computing the mutual information between L$_{sat}$ and secondary properties and explore how this mutual information varies as a function of stellar mass and when separating the sample into star-forming and quiescent central galaxies. We find that absolute r-band magnitude correlates more strongly with L$_{sat}$ than stellar mass across all galaxy populations; and that effective radius, velocity dispersion, and S\'ersic index do so as well for star-forming and quiescent galaxies. L$_{sat}$ is sensitive to both the mass of the host halo as well as the halo formation history, with younger halos having higher L$_{sat}$. L$_{sat}$ by itself cannot distinguish between these two effects, but measurements of galaxy large-scale environment can break this degeneracy. For star-forming central galaxies, we find that r$_{\rm eff}$, $\sigma_v$, and S\'ersic index all correlate with large-scale density, implying that these halo age plays a role in determining these properties. For quiescent galaxies, we find that all secondary properties are independent of environment, implying that correlations with L$_{sat}$ are driven only by halo mass. These results are a significant step forward in quantifying the full extent of the galaxy-halo connection, and present a new test of galaxy formation models.

[10]  arXiv:1911.04510 [pdf, other]

Title: Global axisymmetric simulations of photoevaporation and magnetically driven protoplanetary disk winds

Authors: Peter J. Rodenkirch, Hubert Klahr, Christian Fendt, Cornelis P. Dullemond

Comments: Accepted for publication in Astronomy & Astrophysics

Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)

Photoevaporation and magnetically driven winds are two independent mechanisms to remove mass from protoplanetary disks. In addition to accretion, the effect of these two principles acting concurrently could be significant and the transition between those two has not been extensively studied and quantified in the literature yet. In order to contribute to the understanding of disk winds, we present the phenomena emerging in the framework of two-dimensional axisymmetric, non-ideal magnetohydrodynamic simulations including EUV-/ X-ray driven photoevaporation. Of particular interest are the examination of the transition region between photoevaporation and magnetically driven wind, the possibility of emerging magneto-centrifugal wind effects, as well as the morphology of the wind itself depending on the strength of the magnetic field. We use the PLUTO code in a 2.5D axisymmetric configuration with additional treatment of EUV-/ X-ray heating and dynamic ohmic diffusion based on a semi-analytical chemical model. We identify the transition between both outflow types to occur for values of the initial plasma beta $\beta \geq 10^7$, while magnetically driven winds generally outperform photoevaporation for stronger fields. In our simulations we observe irregular and asymmetric outflows for stronger magnetic fields. In the weak field regime the photoevaporation rates are slightly lowered by perturbations of the gas density in the inner regions of the disk. Overall, our results predict a wind with a lever arm smaller than 1.5, consistent with a hot magneto-thermal wind. Stronger accretion flows are present for values of $\beta < 10^7$.

[11]  arXiv:1911.04517 [pdf, other]

Title: VIS3COS: III. environmental effects on the star formation histories of galaxies at z~0.8 seen in [OII], H$δ$, and Dn4000

Authors: Ana Paulino-Afonso, David Sobral, Behnam Darvish, Bruno Ribeiro, Ian Smail, Philip Best, Andra Stroe, Joseph Cairns

Comments: 20 pages, 13 figures, accepted for publication in A&A

Subjects: Astrophysics of Galaxies (astro-ph.GA)

[ABRIDGED] We present spectroscopic observations of 466 galaxies in and around a superstructure at $z\sim0.84$ targeted by the VIMOS Spectroscopic Survey of a Supercluster in the COSMOS field (VIS$^{3}$COS). We use [OII]$\lambda$3727, H$\delta$, and $D_n4000$ to trace the recent, mid-, and long-term star formation histories and investigate how stellar mass and the local environment impacts those. By studying trends both in individual and composite galaxy spectra, we find that both stellar mass and environment play a role in the observed galactic properties. We find that the median [OII] equivalent width (|EW$_\mathrm{[OII]}|$) decreases from $27\pm2$ {\AA} to $2.0_{-0.4}^{+0.5}$ {\AA} and $D_n4000$ increases from $1.09\pm0.01$ to $1.56\pm0.03$ with increasing stellar mass (from $\sim10^{9.25}$ to $\sim10^{11.35}\ \mathrm{M_\odot}$). Concerning the dependence on the environment, we find that at fixed stellar mass |EW$_\mathrm{[OII]}|$ is tentatively lower in higher density environments. Regarding $D_n4000$, we find that the increase with stellar mass is sharper in denser environments, hinting that such environments may accelerate galaxy evolution. Moreover, we find larger $D_n4000$ values in denser environments at fixed stellar mass, suggesting that galaxies are on average older and/or more metal-rich in such dense environments. This set of tracers depicts a scenario where the most massive galaxies have, on average, the lowest sSFRs and the oldest stellar populations (age $\gtrsim1$ Gyr, showing a mass-downsizing effect). We also hypothesize that the observed increase in star formation (higher EW$_\mathrm{[OII]|}$, higher sSFR) at intermediate densities may lead to quenching since we find the quenched fraction to increase sharply from the filament to cluster-like regions at similar stellar masses.

[12]  arXiv:1911.04518 [pdf, other]

Title: Chemical Evolution in the Milky Way: Rotation-based ages for APOGEE-Kepler cool dwarf stars

Authors: Zachary R. Claytor, Jennifer L. van Saders, Angela R. G. Santos, Rafael A. Garcia, Savita Mathur, Jamie Tayar, Marc H. Pinsonneault, Matthew Shetrone

Comments: 22 pages, 11 figures, 3 tables. Submitted to AAS Journals. Electronic version of Table 3 is available as ancillary file (sidebar on the right). For a brief video explaining this paper, see this https URL The code developed to interact with, interpolate, and sample the stellar models is publicly available at this https URL

Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA)

We use models of stellar angular momentum evolution to determine ages for $\sim500$ stars in the APOGEE-\textit{Kepler} Cool Dwarfs sample. We focus on lower main-sequence stars, where other age-dating tools become ineffective. Our age distributions are compared to those derived from asteroseismic and giant samples and solar analogs. We are able to recover gyrochronological ages for old, lower-main-sequence stars, a remarkable improvement over prior work in hotter stars. Under our model assumptions, our ages have a median relative uncertainty of $14\%$, comparable to the age precision inferred for more massive stars using traditional methods. We investigate trends of galactic $\alpha$-enhancement with age, finding evidence of a detection threshold between the age of the oldest $\alpha$-poor stars and that of the bulk $\alpha$-rich population. We argue that gyrochronology is an effective tool reaching ages of 10--12 Gyr in K- and early M-dwarfs. Finally, we present the first effort to quantify the impact of detailed abundance patterns on rotational evolution. We estimate a $\sim15\%$ bias in age for cool, $\alpha$-enhanced (+ 0.4 dex) stars when standard solar-abundance-pattern rotational models are used for age inference, rather than models that appropriately account for $\alpha$-enrichment.

[13]  arXiv:1911.04520 [pdf, other]

Title: Testing interacting dark matter and dark energy model with cosmological data

Authors: Gong Cheng, Yinzhe Ma, Fengquan Wu, Jiajun Zhang, Xuelei Chen

Comments: 9 pages, 8 figures

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Theory (hep-th)

We investigate the model of dark matter-dark energy (DM-DE) interaction with coupling strength proportional to the multiplication of dark sector densities with different power indices $Q = \gamma \rho_{\rm c}^{\alpha} \rho_{\rm d}^{\beta}$. We first investigate the modification of the cosmic expansion history, and then further develop the formalism to take into account the cosmological perturbations and dark matter temperature evolution. We then use the latest observational cosmology data, including cosmic microwave background (CMB) data, baryon acoustic oscillations (BAO) data, redshift-space distortion (RSD) data and Type Ia supernovae (SNe) data to constrain the model parameters. We find in the phantom region, a positive $\alpha$ is preferred by the data above $2\, \sigma$ statistic significance. If we choose the power indices to be integers or half-integers for {\it plausible} physics of particle interaction, the allowed values within $1\, \sigma$ confidence regions are $\alpha = 0.5$ and $\beta = 0, 0.5, 1$. The inclusion of BAO and RSD data from large-scale structure and SNe data improves the constraints significantly. Our model predicts lower values of $f(z) \sigma_8(z)$ at $z<1$ comparing to $\Lambda$CDM model, which alleviates the tension of $\Lambda$CDM with various RSD data from optical galaxy surveys. Overall, the DM-DE interaction model is consistent with the current observational data, especially providing a better fit to the RSD data.

[14]  arXiv:1911.04524 [pdf, ps, other]

Title: Hyperbolic Orbits in the Solar System: Interstellar Origin or Perturbed Oort Cloud Comets?

Authors: Arika Higuchi, Eiichiro Kokubo

Comments: 9 pages, 7 figures, accepted for publication in MNRAS

Subjects: Earth and Planetary Astrophysics (astro-ph.EP)

We study the dynamical properties of objects in hyperbolic orbits passing through the inner Solar system in the context of two different potential sources: interstellar space and the Oort cloud. We analytically derive the probability distributions of eccentricity, $e$, and perihelion distance, $q$, for each source and estimate the numbers of objects produced per unit of time as a function of these quantities. By comparing the numbers from the two sources, we assess which origin is more likely for a hyperbolic object having a given eccentricity and perihelion distance. We find that the likelihood that a given hyperbolic object is of interstellar origin increases with decreasing eccentricity and perihelion. Conversely, the likelihood that a hyperbolic object has been scattered from the Oort cloud by a passing star increases with decreasing eccentricity and increasing perihelion. By carefully considering their orbital elements, we conclude that both 1I/2017 U1 'Oumuamua ($e\simeq$ 1.2 and $q\simeq$ 0.26 au) and 2I/2019 Q4 Borisov ($e\simeq$ 3.3 and $q\simeq$ 2 au) are most likely of interstellar origin, not scattered from the Oort cloud. However, we also find that Oort cloud objects can be scattered into hyperbolic orbits like those of the two known examples, by sub-stellar and even sub-Jovian mass perturbers. This highlights the need for better characterization of the low mass end of the free-floating brown dwarf and planet population.

[15]  arXiv:1911.04527 [pdf, other]

Title: Line intensity mapping: a "novel" window to the cosmic web

Authors: José Fonseca

Comments: Invited talk at the IAU Symposium 355: The Realm of the Low Surface Brightness Universe, Tenerife, Spain, July 2019; to appear in The Realm of the Low-Surface-Brightness Universe, Proceedings IAU Symposium No. 355, 2019, Eds. D. Valls-Gabaud, I. Trujillo & S. Okamoto [15 pages, 5 figures, 1 table]

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Astrophysics of Galaxies (astro-ph.GA)

Intensity mapping has been attracting increasing interest as a way to study galaxy evolution and the large scale structure of the Universe. Instead of detecting individual galaxies, we measure the integrated emission from a volume of the universe. Contrary to galaxy surveys, it includes light from the faintest objects in the cosmic web. We will start this overview by introducing line intensity mapping and review its current observational status. We will enumerate the most prominent emission lines for intensity mapping and discuss how to model their observed signal. The prospects of using this technique in the near future are very good with a wide range of experiments in different parts of the electromagnetic spectrum. As for any other observational tool, intensity mapping is not free of systematic uncertainties, some of which are intrinsic to it. We will briefly discuss them as well as the means to deal with foreground and background contamination. Here, we will focus on the science cases for intensity mapping in the post-reionization universe. These range from the history of star formation to measuring the acoustic scale and the fundamental physics.

[16]  arXiv:1911.04544 [pdf, other]

Title: Simultaneous Millimeter-wave and X-ray monitoring of the Seyfert Galaxy NGC 7469

Authors: Ehud Behar, Shai Kaspi, Gabriel Paubert, Nicolas Billot, Uria Peretz, Ranieri D. Baldi, Ari Laor, Jelle Kaastra, Missagh Mehdipour

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)

We report on daily monitoring of the Seyfert galaxy NGC 7469, around 95 GHz and 143 GHz, with the IRAM 30 m radio telescope, and with the Swift X-Ray and UV/Optical telescopes, over an overlapping period of 45 days. The source was observed on 36 days with IRAM, and the flux density in both mm bands was on average $\sim 10$ mJy, but varied by $\pm50\%$, and by up to a factor of 2 between days. The present IRAM variability parameters are consistent with earlier CARMA monitoring, which had only 18 data points. The X-ray light curve of NGC 7469 over the same period spans a factor of 5 in flux with small uncertainties. Similar variability in the mm-band and in the X-rays lends support to the notion of both sources originating in the same physical component of the AGN, likely the accretion disk corona. Simultaneous monitoring in eight UV/optical bands shows much less variability than the mm and X-rays, implying this light originates from a different AGN component, likely the accretion disk itself. We use a tentative 14 day lag of the X-ray light curve with respect to the 95 GHz light curve to speculate on coronal implications. More precise mm-band measurements of a sample of X-ray-variable AGN are needed, preferably also on time scales of less than a day where X-rays vary dramatically, in order to properly test the physical connection between the two bands.

[17]  arXiv:1911.04551 [pdf, other]

Title: 3D structure of HII region Sh2-235 from tunable filter optical observations

Authors: M. S. Kirsanova, P. A. Boley, A. V. Moiseev, D. S. Wiebe, R. I. Uklein

Comments: submitted to MNRAS, comments are welcome

Subjects: Astrophysics of Galaxies (astro-ph.GA); Solar and Stellar Astrophysics (astro-ph.SR)

We present observations of the H-alpha, H-beta, [SII] 6716, 6731 and [NII] 6583 emission lines in the galactic HII region Sh2-235 with the Mapper of Narrow Galaxy Lines (MaNGaL), a tunable filter at the 1-m telescope of Special Astrophysical Observatory of the Russian Academy of Sciences. We show that the HII region is obscured by neutral material with AV = 2-4 mag. The area with the highest AV is situated to the south-west from the ionizing star and coincides with a maximum detected electron density of >=150 cm(-3). The combination of these results with archive AKARI far-infrared data allows us to estimate the contribution of the front and rear walls to the total column density of neutral material in S235, and explain the three-dimensional structure of the region. The HII region consist of a denser, more compact portion deeply embedded in the neutral medium and the less dense and obscured gas. The front and rear walls of the HII region are inhomogeneous, with the material in the rear wall having a higher column density. We find a two-sided photodissociation region in the dense clump S235 East 1, illuminated by a UV field with G0=50-70 and 200 in the western and eastern parts, respectively.

[18]  arXiv:1911.04557 [pdf, other]

Title: The Milky Way total mass profile as inferred from Gaia DR2

Authors: Marius Cautun, Alejandro Benitez-Llambay, Alis J. Deason, Carlos S. Frenk, Azadeh Fattahi, Facundo A. Gómez, Robert J. J. Grand, Kyle A. Oman, Julio F. Navarro, Christine M. Simpson

Comments: 21 pages, 14 figures, main results: figs 3, 7, 10 and 11; submitted to MNRAS, comments are welcomed

Subjects: Astrophysics of Galaxies (astro-ph.GA)

We determine the Milky Way (MW) mass profile inferred from fitting physically motivated models to the \textit{Gaia} DR2 Galactic rotation curve and other data. Using various hydrodynamical simulations of MW-mass haloes, we show that the presence of baryons induces a contraction of the dark matter (DM) distribution in the inner regions, $r\lesssim 20$ kpc. We provide an analytic expression that relates the baryonic distribution to the change in the DM halo profile. For our galaxy, the contraction increases the enclosed DM halo mass by factors of roughly 1.3, 2 and 4 at radial distances of 20, 8 and 1 kpc, respectively compared to an uncontracted halo. Ignoring this contraction results in systematic biases in the inferred halo mass and concentration. We provide a best-fitting contracted NFW halo model to the MW rotation curve that matches the data very well. The best-fit has a DM halo mass, $M_{200}^{\rm DM}=0.99_{-0.20}^{+0.18}\times10^{12} M_\odot$, and concentration before baryon contraction of $8.2_{-1.5}^{+1.7}$, which lie close to the median halo mass--concentration relation predicted in $\Lambda$CDM. The inferred total mass, $M_{200}^{\rm total}=1.12_{-0.22}^{+0.20} \times 10^{12} M_\odot$, is in good agreement with recent measurements. The model gives a MW stellar mass of $4.99_{-0.50}^{+0.34}\times10^{10} M_\odot$, of which $60\%$ is contained in the thin stellar disc, with a bulge-to-total ratio of 0.2. We infer that the DM density at the Solar position is $\rho_{\odot}^{\rm DM} = 9.0_{-0.4}^{+0.5}\times10^{-3} M_\odot \rm{pc}^{-3} \equiv 0.34_{-0.02}^{+0.02}~\rm{GeV}~\rm{cm}^{-3}$. The rotation curve data can also be fitted with an uncontracted NFW halo model, but with very different DM and stellar parameters. The observations prefer the physically motivated contracted NFW halo, but the measurement uncertainties are too large to rule out the uncontracted NFW halo.

[19]  arXiv:1911.04564 [pdf, ps, other]

Title: The Carnegie Supernova Project II. Early observations and progenitor constraints of the Type Ib supernova LSQ13abf

Authors: M. D. Stritzinger (Aarhus), F. Taddia, S. Holmbo, E. Baron, C. Contreras, E. Karamehmetoglu, M. M. Phillips, J. Sollerman, N. B. Suntzeff, J. Vinko, C. Ashall, C. Avila, C. R. Burns, A. Campillay, S. Castellon, G. Folatelli, L. Galbany, P. Hoeflich, E. Y. Hsiao, G. H. Marion, N. Morrell, J. C.Wheeler

Comments: 29 pages, including 9 of text, 17 figures, and 11 tables. Includes response to referee's comments. Constructive comments are welcome. Abstract is abridged

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)

Supernova LSQ13abf was discovered soon after explosion by the La Silla-QUEST Survey and followed by the CSP II at optical and near-IR wavelengths. Our analysis indicates LSQ13abf was discovered within two days of explosion and its first 10 days of evolution reveal a B-band light curve with an abrupt drop in luminosity. Contemporaneously, the V-band light curve exhibits a rise towards a first peak and the r- and i-band light curves show no early peak. The early light-curve evolution of LSQ13abf is reminiscent of the post explosion cooling phase observed in the Type Ib SN 2008D, and the similarity between the two objects extends over weeks. Spectroscopically, LSQ13abf resembles SN 2008D with P Cygni He I features that strengthen over time. Spectral energy distributions are constructed from broad-band photometry, and by fitting black-body (BB) functions a UVOIR light curve is constructed, and the underlying BB-temperature and BB-radius profiles are estimated. Explosion parameters are estimated by simultaneously fitting an Arnett model to the UVOIR light curve and the velocity evolution derived from spectral features, and a post-shock breakout cooling model to the first two epochs of the bolometric evolution. This combined model suggests an explosion energy of 1.3x10$^{51}$ ergs, a relatively high ejecta mass of 5.94 M$_{\odot}$, a Ni mass of 0.16 M$_{\odot}$, and a progenitor-star radius of 28.0 R$_{\odot}$. The ejecta mass suggests the origins of LSQ13abf lie with a >25 M$_{\odot}$ ZAMS progenitor and its radius is three and nine times larger than values estimated from the same analysis applied to observations of SNe 2008D and 1999ex, respectively. Alternatively, comparison of hydrodynamical simulations of >20-25 M$_{\odot}$ ZAMS progenitors that evolve to pre-SN envelope masses around 10 M$_{\odot}$ and extended (~100 R$_{\odot}$) envelopes also match the observations of LSQ13abf.

[20]  arXiv:1911.04567 [pdf, ps, other]

Title: Characterization of the C-RED 2: A High Frame Rate Near-Infrared Camera

Authors: Rose K. Gibson, Rebecca Oppenheimer, Christopher T. Matthews, Gautam Vasisht

Comments: Accepted in JATIS, 17 pages, 9 figures

Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM)

A new wave of precision radial velocity instruments will open the door to exploring the populations of companions of low mass stars. The Palomar Radial Velocity Instrument (PARVI) will be optimized to detect radial velocity signals of cool K and M stars with an instrument precision floor of 30 cm/s. PARVI will operate in the $\lambda = 1.2-1.8$ $\rm{\mu m}$ wavelength range with a spectral resolution of $\lambda/\Delta\lambda$ $\sim$100,000. It will operate on the Palomar 5.1 m Hale telescope and use Palomar's PALM-3000 adaptive optics system, single-mode fibers, and an H band laser frequency comb to probe and characterize the population of planets around cool, red stars. In this work we describe the performance of the PARVI guide camera: a C-RED 2 from First Light Advanced Imagery. The C-RED 2 will be used in a tip-tilt loop which requires fast readout at low noise levels to eliminate any residual guide errors and ensure the target starlight stays centered on the fiber. At -40$^{\circ}$ C and a frame rate of 400 FPS in non-destructive read mode, the C-RED 2 has a combined dark and background current of 493 $e^-$/s. Using up-the-ramp sampling we are able to reduce the read noise to 21.2 e$^-$. With the C-RED 2, PARVI will be able to guide using targets as faint as 14.6 H magnitude.

[21]  arXiv:1911.04572 [pdf, ps, other]

Title: Photometric Redshift Realism: A Technique for Reducing Catastrophic Outlier Redshift Estimates in Large-Scale Surveys

Authors: M. Wyatt, J. Singal

Comments: 10 pages, 11 figures, 1 table, submitted to MNRAS

Subjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO); Instrumentation and Methods for Astrophysics (astro-ph.IM)

We present results of using individual galaxies' effective redshift probability density information as a method of identifying potential catastrophic outliers in empirical photometric redshift estimation. In the course we develop a method of modification of the redshift distribution of training sets to improve both the baseline accuracy of high redshift (z>1.5) estimation as well as catastrophic outlier mitigation. We demonstrate these using two real test data sets and one simulated test data set spanning a wide redshift range (0<z<4). We present these results in the context of "photometric redshift realism" and aim to show that the methods and results presented here can inform a 'prescription' that can be applied as a realistic photometric redshift estimation scenario for a hypothetical large-scale survey. We find that with appropriate optimization, we can identify a large percentage (>30%) of catastrophic outlier galaxies while simultaneously incorrectly flagging only a small percentage (<7% and in many cases <3%) of non-outlier galaxies as catastrophic outliers. We find also that our training set redshift distribution modification results in a significant decrease (>10%) in the percentage of outlier galaxies greater than z=1.5 with only a small increase (<3%) in the percentage of outlier galaxies less than z=1.5 compared to the unmodified training set. In addition, we find that this modification can in some cases decrease the percentage of incorrectly identified non-outlier galaxies by almost 20%, while in other cases cause only a small (<1%) increase in this metric.

[22]  arXiv:1911.04579 [pdf, other]

Title: The Normalization and Slope of the Dark Matter (Sub-)Halo Mass Function on Sub-Galactic Scales

Authors: Andrew J. Benson (1) ((1) Carnegie Institution for Science)

Comments: 9 pages, submitted to MNRAS

Subjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO)

Simulations of cold dark matter make robust predictions about the slope and normalization of the dark matter halo and subhalo mass functions on small scales. Recent observational advances utilizing strong gravitational lensing have demonstrated the ability of this technique to place constraints on these quantities on subgalactic scales corresponding to dark matter halo masses of $10^6$--$10^9\mathrm{M}_\odot$. On these scales the physics of baryons, which make up around 17% of the matter content of the Universe but which are not included in pure dark matter N-body simulations, are expected to affect the growth of structure and the collapse of dark matter halos. In this work we develop a semi-analytic model to predict the amplitude and slope of the dark matter halo and subhalo mass functions on subgalactic scales in the presence of baryons. We find that the halo mass function is suppressed by up to 25%, and the slope is modified, ranging from $-1.916$ to $-1.868$ in this mass range. These results are consistent with current measurements, but differ sufficiently from the expectations for a dark matter only universe that it may be testable in the near future.

[23]  arXiv:1911.04589 [pdf, ps, other]

Title: Detailed Model of the Growth of Fluffy Dust Aggregates in a Protoplanetary Disk: Effects of Nebular Conditions

Authors: C. Xiang, L.S. Matthews, A. Carballido, T.W. Hyde

Subjects: Earth and Planetary Astrophysics (astro-ph.EP)

Coagulation of dust aggregates plays an important role in the formation of planets and is of key importance to the evolution of protoplanetary disks (PPDs). Characteristics of dust, such as the diversity of particle size, porosity, charge, and the manner in which dust couples to turbulent gas, affect the collision outcome and the rate of dust growth. Here we present a numerical model of the evolution of the dust population within a PPD which incorporates all of these effects. The probability that any two particles collide depends on the particle charge, cross-sectional area and their relative velocity. The actual collision outcome is determined by a detailed collision model which takes into account the aggregate morphology, trajectory, orientation, and electrostatic forces acting between charged grains. The data obtained in this research reveal the characteristics of dust populations in different environments at the end of the hit-and-stick growth, which establishes the foundation for the onset of the next growth stage where bouncing, mass transfer and fragmentation become important. For a given level of turbulence, neutral and weakly charged particles collide more frequently and grow faster than highly charged particles. However, highly charged particles grow to a larger size before reaching the bouncing barrier, and exhibit a "Runaway" growth, in which a few large particles grow quickly by accreting smaller particles while the rest of the population grows very slowly. In general, highly charged aggregates have a more compact structure and are comprised of larger monomers than neutral/weakly charged aggregates. The differences in the particle structure/composition not only affect the threshold velocities for bouncing and fragmentation, but also change the scattering and absorption opacity of dust, influencing the appearance of PPDs.

[24]  arXiv:1911.04591 [pdf, other]

Title: New Limits on the Low-frequency Radio Transient Sky Using 31 hr of All-sky Data with the OVRO-LWA

Authors: M. M. Anderson, G. Hallinan, M. W. Eastwood, R. M. Monroe, T. A. Callister, J. Dowell, B. Hicks, Y. Huang, N. E. Kassim, J. Kocz, T. J. W. Lazio, D. C. Price, F. K. Schinzel, G. B. Taylor

Comments: 20 pages, 8 figures, ApJ accepted

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); Instrumentation and Methods for Astrophysics (astro-ph.IM)

We present the results of the first transient survey from the Owens Valley Radio Observatory Long Wavelength Array (OVRO-LWA) using 31 hr of data, in which we place the most constraining limits on the instantaneous transient surface density at timescales of 13 s to a few minutes and at frequencies below 100 MHz. The OVRO-LWA is a dipole array that images the entire viewable hemisphere with 58 MHz of bandwidth from 27 to 84 MHz at 13 s cadence. No transients are detected above a 6.5$\sigma$ flux density limit of 10.5 Jy, implying an upper limit to the transient surface density of $2.5\times10^{-8}$ deg$^{-2}$ at the shortest timescales probed, which is orders of magnitude deeper than has been achieved at sub-100 MHz frequencies and comparable flux densities to date. The nondetection of transients in the OVRO-LWA survey, particularly at minutes-long timescales, allows us to place further constraints on the rate of the potential population of transients uncovered by Stewart et al. (2016). From their transient rate, we expect a detection of $8.4^{+31.8}_{-8.0}$ events, and the probability of our null detection is $1.9^{+644}_{-1.9}\times10^{-3}$, ruling out a transient rate $>1.4\times10^{-4} \text{days}^{-1} \text{deg}^{-2}$ with 95% confidence at a flux density limit of 18.1 Jy, under the assumption of a flat spectrum and wide bandwidth. We discuss the implications of our nondetection for this population and further constraints that can be made on the source spectral index, intrinsic emission bandwidth, and resulting luminosity distribution.

[25]  arXiv:1911.04598 [pdf, other]

Title: The Compositional Diversity of Low-Mass Exoplanets

Authors: Daniel Jontof-Hutter

Comments: 31 pages, 8 figures

Journal-ref: Annual Review of Earth and Planetary Sciences, 2019, vol. 47, p.141-171

Subjects: Earth and Planetary Astrophysics (astro-ph.EP)

Low-mass planets have an extraordinarily diverse range of bulk compositions, from primarily rocky worlds to those with deep gaseous atmospheres. As techniques for measuring the masses of exoplanets are advancing the field towards the terrestrial regime, from ultra-short orbital periods to Venus-like distances, we identify the bounds on planet compositions, where sizes and incident fluxes inform bulk planet properties. In some cases, measurement precisions of planet masses and sizes are approaching the theoretical uncertainties in planet models.
An emerging picture explains aspects of the diversity of low-mass planets although some problems remain; do extreme low density low-mass planets challenge models of atmospheric mass loss? Are planet sizes strictly separated by bulk composition? Why do some stellar characterizations differ between observational techniques?
As the TESS mission begins, low-mass exoplanets around the nearest stars will soon be discovered and characterized with unprecedented precision, permitting more detailed planetary modeling and atmospheric characterization of low mass exoplanets than ever before.

[26]  arXiv:1911.04600 [pdf, other]

Title: WISE2150-7520AB: A very low mass, wide co-moving brown dwarf system discovered through the citizen science project Backyard Worlds: Planet 9

Authors: Jacqueline K. Faherty, Sam Goodman, Dan Caselden, Guillaume Colin, Marc J. Kuchner, Aaron M. Meisner, Jonathan Gagne', Adam C. Schneider, Eileen C. Gonzales, Daniella C. Bardalez Gagliuffi, Sarah E. Logsdon, Katelyn Allers, Adam J. Burgasser, The Backyard Worlds: Planet 9 Collaboration

Comments: ApJ accepted October 2019. 18 pages, 8 Figures, two tables. All tabular data is available on a viewable/commentable google sheet here: this https URL

Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Earth and Planetary Astrophysics (astro-ph.EP)

We report the discovery of WISE2150-7520AB (W2150AB): a widely separated (~ 341 AU) very low mass L1 + T8 co-moving system. The system consists of the previously known L1 primary 2MASS J21501592-7520367 and a newly discovered T8 secondary found at position 21:50:18.99 -75:20:54.6 (MJD=57947) using Wide-field Infrared Survey Explorer (WISE) data via the Backyard Worlds: Planet 9 citizen science project. We present Spitzer ch1 and ch2 photometry (ch1-ch2= 1.41 +/-0.04 mag) of the secondary and FIRE prism spectra of both components. The sources show no peculiar spectral or photometric signatures indicating that each component is likely field age. Using all observed data and the Gaia DR2 parallax of 41.3593 +/- 0.2799 mas for W2150A we deduce fundamental parameters of log(Lbol/Lsun)=-3.69 +/- 0.01, Teff=2118 +/- 62 K, and an estimated mass=72 +/- 12 MJup for the L1 and log(Lbol/Lsun)=-5.64 +/- 0.02, Teff=719 +/- 61 K, and an estimated mass=34 +/- 22 MJup for the T8. At a physical separation of ~341 AU this system has Ebin = 10^41 erg making it the lowest binding energy system of any pair with Mtot < 0.1 Msun not associated with a young cluster. It is equivalent in estimated mass ratio, Ebin, and physical separation to the ~ 2 Myr M7.25 + M8.25 binary brown dwarf 2MASS J11011926-7732383AB (2M1101AB) found in the Chameleon star forming region. W2150AB is the widest companion system yet observed in the field where the primary is an L dwarf or later.

[27]  arXiv:1911.04612 [pdf]

Title: Chemical Properties of the Local Galactic Disk and Halo. I. Fundamental Properties of 1,544 Nearby, High Proper-Motion M dwarfs and subdwarfs

Authors: Neda Hejazi, Sebastien Lepine, Derek Homeier, R. Michael Rich, Michael M. Shara

Comments: 53 pages, 43 figures, 10 tables, accepted for publication in AJ

Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA)

Large numbers of low-to-medium resolution spectra of M-type dwarf stars from both the local Galactic disk and halo are available from various surveys. In order to fully exploit these data, we develop a template-fit method using a set of empirically assembled M dwarf/subdwarf classification templates, based on the measurements of the TiO and CaH molecular bands, to classify M dwarfs/subdwarfs by spectral type and metallicity class. We further present a pipeline to automatically determine the effective temperature, metallicity ([M/H]), alpha-element to iron abundance ratio ([alpha/Fe]), and surface gravity of M dwarfs/subdwarfs using the latest version of BT-Settl model atmospheres. We apply these methods to a set of low-to-medium resolution optical spectra of 1,544 high proper-motion (> 0.4"/yr) M dwarfs/subdwarfs. Our metallicity estimates appear to be consistent with the expected color-magnitude variation of stars relative to atmospheric composition, as our sample shows a clear stratification with respect to metallicity in the Gaia H-R diagram. Furthermore, the measured chemical parameters of the two components in 48 binary systems are in a good agreement with each other, which suggest a precision of 0.22 dex in [M/H], 0.08 dex in [alpha/Fe], and 0.16 dex in the combined index [alpha/Fe]+[M/H]. There is also a good consistency between metallicity class, obtained from the empirical classification templates, and the index [alpha/Fe]+[M/H] (~ [alpha/H]), obtained from model-fitting, which means that the more easily measured metallicity class can be used as a relatively reliable indicator of absolute alpha-element abundance, [alpha/H], in low-mass stars. Finally, we examine the distribution of our stars in the [alpha/Fe] vs. [M/H] diagram, which shows evidence of clustering in chemical abundance makeup, suggestive of discrete populations among the local disk and halo stars.

[28]  arXiv:1911.04642 [pdf, other]

Title: Bright $γ$-ray flares observed in GRB131108A

Authors: M. Ajello, M. Arimoto, K. Asano, M. Axelsson, L. Baldini, G. Barbiellini, D. Bastieri, R. Bellazzini, A. Berretta, E. Bissaldi, R. D. Blandford, R. Bonino, E. Bottacini, J. Bregeon, P. Bruel, R. Buehler, S. Buson, R. A. Cameron, R. Caputo, P. A. Caraveo, E. Cavazzuti, S. Chen, G. Chiaro, S. Ciprini, D. Costantin, S. Cutini, F. D'Ammando, P. de la Torre Luque, F. de Palma, N. Di Lalla, L. Di Venere, F. Fana Dirirsa, S. J. Fegan, A. Franckowiak, Y. Fukazawa, P. Fusco, F. Gargano, D. Gasparrini, N. Giglietto, F. Giordano, M. Giroletti, D. Green, I. A. Grenier, M.-H. Grondin, S. Guiriec, E. Hays, D. Horan, G. J 'ohannesson, D. Kocevski, M. Kovac'evic', M. Kuss, S. Larsson, L. Latronico, J. Li, I. Liodakis, F. Longo, F. Loparco, M. N. Lovellette, P. Lubrano, S. Maldera, A. Manfreda, et al. (50 additional authors not shown)

Comments: accepted to ApJL, 10 pages, 3 figures, 2 tables

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)

GRB 131108A is a bright long Gamma-Ray Burst (GRB) detected by the Large Area Telescope and the Gamma-ray Burst Monitor on board the \textit{Fermi Gamma-ray Space Telescope}. Dedicated temporal and spectral analyses reveal three $\gamma$-ray flares dominating above 100 MeV, which are not directly related to the prompt emission in the GBM band (10 keV--10 MeV). The high-energy light curve of GRB 131108A (100 MeV -- 10 GeV) shows an unusual evolution: a steep decay, followed by three flares with an underlying emission, and then a long-lasting decay phase. The detailed analysis of the $\gamma$-ray flares finds that the three flares are 6 -- 20 times brighter than the underlying emission and are similar to each other. The fluence of each flare, (1.6 $\sim$ 2.0) $\times$ 10$^{-6}$ erg cm$^{-2}$, is comparable to that of emission during the steep decay phase, 1.7 $\times$ 10$^{-6}$ erg cm$^{-2}$. The total fluence from three $\gamma$-ray flares is 5.3 $\times$ 10$^{-6}$ erg cm$^{-2}$. The three $\gamma$-ray flares show properties similar to the usual X-ray flares that are sharp flux increases, occurring in $\sim$ 50\% of afterglows, in some cases well after the prompt emission. Also, the temporal and spectral indices during the early steep decay phase and the decaying phase of each flare show the consistency with a relation of the curvature effect ($\hat{\alpha}$ = 2 + $\hat{\beta}$), which is the first observational evidence of the high-latitude emission in the GeV energy band.

[29]  arXiv:1911.04645 [pdf, ps, other]

Title: Survey of Period Variations of Superhumps in SU UMa-Type Dwarf Novae. X: The Tenth Year (2017)

Authors: Taichi Kato, Keisuke Isogai, Yasuyuki Wakamatsu (Kyoto U), Franz-Josef Hambsch, Hiroshi Itoh, Tamas Tordai, Tonny Vanmunster, Pavol A. Dubovsky, Igor Kudzej, Tomas Medulka, Mariko Kimura, Ryuhei Ohnishi, Berto Monard, Elena P. Pavlenko, Kirill A. Antonyuk, Nikolaj V. Pit, Oksana I. Antonyuk, Julia V. Babina, Aleksei V. Baklanov, Aleksei A. Sosnovskij, Roger D. Pickard, Yutaka Maeda, Enrique de Miguel, Stephen M. Brincat, Domenico Licchelli, Lewis M. Cook, Sergey Yu. Shugarov, Anna M. Zaostrojnykh, Drahomir Chochol, Polina Golysheva, Natalia Katysheva, Alexandra M. Zubareva, Geoff Stone, Kiyoshi Kasai, Peter Starr, Colin Littlefield, Seiichiro Kiyota, Maksim V. Andreev, Alexandr V. Sergeev, Javier Ruiz, Gordon Myers, Andrii O. Simon, Volodymyr V. Vasylenko, Francisco Soldan, Yenal Ogmen, Kazuhiro Nakajima, et al. (23 additional authors not shown)

Comments: The main text and Supporting information are combined in this arXiv version. Accepted for publication in PASJ

Subjects: Solar and Stellar Astrophysics (astro-ph.SR)

Continuing the project described by Kato et al. (2009, PASJ, 61, S395, arXiv/0905.1757), we collected times of superhump maxima for 102 SU UMa-type dwarf novae observed mainly during the 2017 season and characterized these objects. WZ Sge-type stars identified in this study are PT And, ASASSN-17ei, ASASSN-17el, ASASSN-17es, ASASSN-17fn, ASASSN-17fz, ASASSN-17hw, ASASSN-17kd, ASASSN-17la, PNV J20205397$+$2508145 and TCP J00332502$-$3518565. We obtained new mass ratios for 7 objects using growing superhumps (stage A). ASASSN-17gf is an EI Psc-type object below the period minimum. CRTS J080941.3+171528 and DDE 51 are objects in the period gap and both showed long-lasting phase of stage A superhumps. We also summarized the recent advances in understanding of SU UMa-type and WZ Sge-type dwarf novae.

[30]  arXiv:1911.04653 [pdf, other]

Title: Cosmological evolution of orientations of cluster-sized dark matter haloes and their central galaxies in the Horizon-AGN simulation

Authors: Taizo Okabe, Takahiro Nishimichi, Masamune Oguri, Sébastien Peirani, Tetsu Kitayama, Shin Sasaki, Yasushi Suto, Christophe Pichon, Yohan Dubois

Comments: 14 pages, 11 figures

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Astrophysics of Galaxies (astro-ph.GA)

It is known observationally that the major axes of galaxy clusters and their brightest cluster galaxies are roughly aligned with each other. To understand the origin of the alignment, we identify 40 cluster-sized dark matter (DM) haloes with masses higher than $5\times10^{13}~M_{\odot}$ and their central galaxies (CGs) at $z\approx 0$ in the Horizon-AGN cosmological hydrodynamical simulation. We trace the progenitors at 50 different epochs between $0<z<5$. We then fit their shapes and orientations with a triaxial ellipsoid model. While the orientations of both DM haloes and CGs change significantly due to repeated mergers and mass accretions, their relative orientations are well aligned at each epoch even at high redshifts, $z>1$. The alignment becomes tighter with cosmic time; the major axes of the CGs and their host DM haloes at present are aligned on average within $\sim 30^{\circ}$ in the three dimensional space and $\sim 20^{\circ}$ in the projected plane. The orientations of the major axes of DM haloes on average follow one of the eigen-vectors of the surrounding tidal field that corresponds to the {\it slowest collapsing} (or even stretching) mode, and the alignment with the tidal field also becomes tighter. This implies that the orientations of CGs and DM haloes at the present epoch are largely imprinted in the primordial density field of the Universe, whereas strong dynamical interactions such as mergers are important to explain their mutual alignment at each epoch.

[31]  arXiv:1911.04670 [pdf, other]

Title: Residual Smoothing: Using Mocks to Correct Model Covariance Matrices

Authors: Ross O'Connell

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)

Abstract Covariance matrix estimation is a challenging problem in cosmology. Recent work has shown that model covariance matrices can be precise, and that at relatively large scales they can also be accurate. We introduce a data-driven method that can identify features from a mock covariance matrix that are missing from a corresponding model, then incorporate them into the model without significantly degrading the model's precision. We apply this method to a BOSS-like survey and extend a model covariance to be valid at scales relevant for measurements of Redshift Space Distortions (8-40 Mpc/h), where the galaxy field is significantly non-Gaussian.

[32]  arXiv:1911.04684 [pdf]

Title: Linear-mode avalanche photodiode arrays for low-noise near-infrared imaging in space

Authors: James Gilbert, Alexey Grigoriev, Shanae King, Joice Mathew, Rob Sharp, Annino Vaccarella

Comments: Paper presented at the 70th International Astronautical Congress, 21-25 October 2019, Washington D.C., United States

Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM)

Astronomical observations often require the detection of faint signals in the presence of noise, and the near-infrared regime is no exception. In particular, where the application has short exposure time constraints, we are frequently and unavoidably limited by the read noise of a system. A recent and revolutionary development in detector technology is that of linear-mode avalanche photodiode (LmAPD) arrays. By the introduction of a signal multiplication region within the device, effective read noise can be reduced to <0.2 e-, enabling the detection of very small signals at frame rates of up to 1 kHz. This is already impacting ground-based astronomy in high-speed applications such as wavefront sensing and fringe tracking, but has not yet been exploited for scientific space missions. We present the current status of a collaboration with Leonardo MW - creators of the 'SAPHIRA' LmAPD array - as we work towards the first in-orbit demonstration of a SAPHIRA device in 'Emu', a hosted payload on the International Space Station. The Emu mission will fully benefit from the 'noiseless' gains offered by LmAPD technology as it produces a time delay integration photometric sky survey at 1.4 microns, using compact readout electronics developed at the Australian National University. This is just one example of a use case that could not be achieved with conventional infrared sensors.

[33]  arXiv:1911.04702 [pdf, other]

Title: NuSTAR Discovery of a Compton-thick Dust-obscured Galaxy WISE J0825+3002

Authors: Yoshiki Toba, Satoshi Yamada, Yoshihiro Ueda, Claudio Ricci, Yuichi Terashima, Tohru Nagao, Wei-Hao Wang, Atsushi Tanimoto, Taiki Kawamuro

Comments: 10 pages, 7 figures, and 2 tables, accepted for publication in ApJ

Subjects: Astrophysics of Galaxies (astro-ph.GA); High Energy Astrophysical Phenomena (astro-ph.HE)

We report the discovery of a Compton-thick (CT) dust-obscured galaxy (DOG) at $z$ = 0.89, WISE J082501.48+300257.2 (WISE0825+3002), observed by Nuclear Spectroscopic Telescope Array (NuSTAR). X-ray analysis with the XCLUMPY model revealed that hard X-ray luminosity in the rest-frame 2-10 keV band of WISE0825+3002 is $L_{\rm X}$ (2-10 keV) = $4.2^{+2.8}_{-1.6} \times 10^{44}$ erg s$^{-1}$ while its hydrogen column density is $N_{\rm H}$ = $1.0^{+0.8}_{-0.4} \times 10^{24}$ cm$^{-2}$, indicating that WISE0825+3002 is a mildly CT active galactic nucleus (AGN). We performed the spectral energy distribution (SED) fitting with CIGALE to derive its stellar mass, star formation rate, and infrared luminosity. The estimated Eddington ratio based on stellar mass and integration of the best-fit SED of AGN component is $\lambda_{\rm Edd}$ = 0.70, which suggests that WISE0825+3002 harbors an actively growing black hole behind a large amount of gas and dust. We found that the relationship between luminosity ratio of X-ray and 6 $\mu$m, and Eddington ratio follows an empirical relation for AGNs reported by Toba et al. (2019a).

[34]  arXiv:1911.04714 [pdf, other]

Title: Maximum Entropy Estimation of the Galactic Bulge Morphology via the VVV Red Clump

Authors: Brendan Coleman, Dylan Paterson, Chris Gordon, Oscar Macias, Harrison Ploeg

Comments: 25 pages, 28 figures

Subjects: Astrophysics of Galaxies (astro-ph.GA); High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR)

The abundance and narrow magnitude dispersion of Red Clump (RC) stars make them a popular candidate for mapping the morphology of the bulge region of the Milky Way. Using a semi-analytic derivation of the RC's intrinsic luminosity function, we extracted the three-dimensional density distribution of the RC from deep photometric catalogues of the VISTA Variables in the Via Lactea (VVV) survey. We employed a joint approach of parametric modelling and maximum entropy based non-parametric deconvolution to extract the spatial distribution of the bulge from Ks-band star counts. Assuming two-fold symmetry over the Galactic plane, we obtained our non-parametric model of the bulge over the inner 40 by 40 degrees squared region centred on the Galactic centre with curvature minimising inpainting overcrowded and high extinction regions. Our reconstruction also naturally matches onto a parametric fit to the bulge outside the VVV region. We incorporated into our background model an apparent feature behind the bar previously observed in the VVV survey. We found a range of bulge properties consistent with other recent investigations based on the VVV data. However, our base model does have less dense X-arms than previous analysis and also retains an asymmetry between the near and far arms of the X-bulge. Studies of the Fermi Large Area Telescope (LAT) gamma-ray Galactic centre excess suggest that the excess may be traced by Galactic Bulge distributed sources. Building on the view that the RC sufficiently traces the Galactic bulge morphology, we applied our deconvolved density in a template fitting analysis of this Fermi-LAT GeV excess and found an improvement in the fit compared to previous parametric based templates.

[35]  arXiv:1911.04715 [pdf, ps, other]

Title: The angular resolution of GRAPES-3 EAS array after correction for the shower front curvature

Authors: V.B. Jhansi, S. Ahmad, M. Chakraborty, S.R. Dugad, S.K. Gupta, B. Hariharan, Y. Hayashi, P. Jagadeesan, A. Jain, P. Jain, S. Kawakami, H. Kojima, S. Mahapatra, P.K. Mohanty, S.D. Morris, P.K. Nayak, A. Oshima, D. Pattanaik, P.S. Rakshe, K. Ramesh, B.S. Rao, L.V. Reddy, S. Shibata, F. Varsi, M. Zuberi

Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM)

The angular resolution of an extensive air shower (EAS) array plays a critical role in determining its sensitivity for the detection of point $\gamma$-ray sources in the multi-TeV energy range. The GRAPES-3 an EAS array located at Ooty in India (11.4$^{\circ}$N, 76.7$^{\circ}$E, 2200 m altitude) is designed to study $\gamma$-rays in the TeV-PeV energy range. It comprises of a dense array of 400 plastic scintillators deployed over an area of 25000 m$^2$ and a large area (560 m$^2$) muon telescope. A new statistical method allowed real time determination of the propagation delay of each detector in the GRAPES-3 array. The shape of shower front is known to be curved and here the details of a new method developed for accurate measurement of the shower front curvature is presented. These two developments have led to a sizable improvement in the angular resolution of GRAPES-3 array. It is shown that the curvature depends on the size and age of an EAS. By employing two different techniques, namely, the odd-even and the left-right methods, independent estimates of the angular resolution are obtained. The odd-even method estimates the best achievable resolution of the array. For obtaining the angular resolution, the left-right method is used after implementing the size and age dependent curvature corrections. A comparison of the angular resolution as a function of EAS energy by these two methods shows them be virtually indistinguishable. The angular resolution of GRAPES-3 array is 47$^{\prime}$ for energies E$>$5 TeV and improves to 17$^{\prime}$ at E$>$100 TeV and finally approaching 10$^{\prime}$ at E$>$500 TeV.

[36]  arXiv:1911.04716 [pdf, other]

Title: Further evidence that the Milky Way bar has undergone a buckling phase

Authors: Dylan Paterson, Brendan Coleman, Chris Gordon

Comments: 10 pages, 7 figures

Subjects: Astrophysics of Galaxies (astro-ph.GA)

Studies of the red clump giant population in the inner Milky Way suggest the Galactic bulge/bar has a boxy/peanut/X-shaped structure as predicted by its formation via a disc buckling instability. We used a new non-parametric method of estimating the Galactic bulge morphology that is based on maximum entropy methods. With our maximum entropy deconvolution method we extracted the three-dimensional distribution of the red giant stars in the bulge from deep photometric catalogues of the VISTA Variables in the Via Lactea (VVV) survey. Our high-resolution reconstruction confirms the well known boxy/peanut/X-shaped structure of the bulge and also shows spurs which extend to around three kpc in front of and behind the bulge. One of those spurs is above the major axis of the bulge and the other is below the major axis. This is a key diagnostic of a post-buckling phase of the bulge. Additionally, at distances over 500 pc above or below the Galactic plane we find that the X-arms are on the same side of the bulge major axis as their corresponding spurs. Closer to the Galactic plane, the X-arms are on opposite sides of the major axis of the bulge. This implies a twisting in the X-shape of the bulge.

[37]  arXiv:1911.04736 [pdf, other]

Title: Evidence of a substellar companion to AB Dor C

Authors: J.B. Climent, J.P. Berger, J. C. Guirado, J.M. Marcaide, I. Martí-Vidal, A. Mérand, E. Tognelli, M. Wittkowski

Comments: 8 pages, 5 figures, accepted for publication in ApJ Letters

Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Earth and Planetary Astrophysics (astro-ph.EP)

Studies of fundamental parameters of very low-mass objects are indispensable to provide tests of stellar evolution models that are used to derive theoretical masses of brown dwarfs and planets. However, only objects with dynamically determined masses and precise photometry can effectively evaluate the predictions of stellar models. AB Dor C (0.090 solar masses) has become a prime benchmark for calibration of theoretical evolutionary models of low-mass young stars. One of the ambiguities remaining in AB Dor C is the possible binary nature of this star. We observed AB Dor C with the VLTI/AMBER instrument in low-resolution mode at the J, H and K bands. The interferometric observables at the K-band are compatible with a binary brown dwarf system with tentative components AB Dor Ca/Cb with a K-band flux ratio of 5$\pm$1% and a separation of 38$\pm$1 mas. This implies theoretical masses of 0.072$\pm$0.013 M$_{\rm \odot}$ and 0.013$\pm$0.001 M$_{\rm \odot}$ for each component, near the hydrogen-burning limit for AB Dor Ca, and near the deuterium-burning limit, straddling the boundary between brown dwarfs and giant planets, for AB Dor Cb. The possible binarity of AB Dor C alleviates the disagreement between observed magnitudes and theoretical mass-luminosity relationships.

[38]  arXiv:1911.04740 [pdf, other]

Title: Morphology of CMB fields -- effect of weak gravitational lensing

Authors: Priya Goyal, Pravabati Chingangbam, Stephen Appleby

Comments: 26+1 pages

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)

We study the morphology of the cosmic microwave background temperature and polarization fields using the shape and alignment parameters, $\beta$ and $\alpha$, that are constructed from the contour Minkowski tensor. The primary goal of our paper is to understand the effect of weak gravitational lensing on the morphology of the CMB fields. In order to isolate different physical effects that can be potentially confused with the effect of lensing, we first study the effect of varying the cosmology on $\alpha$ and $\beta$, and show that they are relatively insensitive to variation of cosmological parameters. Next we analyze the signatures of hemispherical anisotropy, and show that information of such anisotropy in $\alpha$ gets washed out at small angular scales and become pronounced only at large angular scales. For $\beta$ we find characteristic distortions which vary with the field threshold. We then study the effect of weak gravitational lensing using simulations of lensed temperature and $E$ and $B$ modes. We quantify the distortion induced in the fields across different angular scales. We find that lensing makes structures of all fields increasingly more anisotropic as we probe down to smaller scales. We find distinct behaviour of morphological distortions as a function of threshold for the different fields. The effect is small for temperature and $E$ mode, while it is significantly large for $B$ mode. Further, we find that lensing does not induce statistical anisotropy, as expected from the isotropic distribution of large scale structure of matter. We expect that the results obtained in this work will provide insights on the reconstruction of the lensing potential.

[39]  arXiv:1911.04742 [pdf, other]

Title: Online Database of Class I Methanol Masers

Authors: Dmitry Ladeyschikov, Olga Bayandina, Andey Sobolev

Comments: Accepted to the Astronomical Journal

Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Astrophysics of Galaxies (astro-ph.GA); Solar and Stellar Astrophysics (astro-ph.SR)

In this paper, we present a database of class I methanol masers. The compiled information from the available literature provides an open and fast access to the data on class I methanol maser emission, including search, analysis and visualization of the extensive maser data set. There is information on individual maser components detected with single-dish observations and maser spots obtained from interferometric data. At the moment the database contains information from ~100 papers, i.e. ~7500 observations and ~650 sites of class I methanol masers. Analysis of the data collected in the database shows that the distribution of class I methanol maser sources is similar to that of class II methanol masers. They are mostly found in the Molecular Ring, where majority of the OB stars are located. The difference between class I and II distributions is the presence of many class I methanol masers in the Nuclear Disk region (Central Molecular Zone). Access to the class I methanol maser database is available online at this http URL

[40]  arXiv:1911.04745 [pdf, other]

Title: Revisited Mass-Radius relations for exoplanets below 120 Earth masses

Authors: J.F. Otegi, F. Bouchy, R. Helled

Comments: 13 pages, 5 figures. Accepted for publication in A&A

Subjects: Earth and Planetary Astrophysics (astro-ph.EP)

The masses and radii of exoplanets are fundamental quantities needed for their characterisation. Studying the different populations of exoplanets is important for understanding the demographics of the different planetary types, which can then be linked to planetary formation and evolution. We present an updated exoplanet catalog based on reliable, robust and as much as possible accurate mass and radius measurements of transiting planets up to 120 $M_{\oplus}$. The resulting mass-radius (M-R) diagram shows two distinct populations, corresponding to rocky and volatile-rich exoplanets which overlap in both mass and radius. The rocky exoplanet population shows a relatively small density variability and ends at mass of $\sim25 M_{\oplus}$, possibly indicating the maximum core mass that can be formed. We use the composition line of pure-water to separate the two populations, and infer two new empirical M-R relations based on this data: $ M = (0.9 \pm 0.06) \ R^{(3.45 \pm 0.12)}$ for the rocky population, and $ M = (1.74 \pm 0.38) \ R^{(1.58 \pm 0.10)}$ for the volatile-rich population. While our results for the two regimes are in agreement with previous studies, the new M-R relations better match the population in the transition-region from rocky to volatile-rich exoplanets, which correspond to a mass range of 5-25 $M_{\oplus}$ and a radius range of 2-3 $R_{\oplus}$.

[41]  arXiv:1911.04761 [pdf, ps, other]

Title: H.E.S.S. detection of very-high-energy gamma-ray emission from the quasar PKS 0736+017

Authors: H.E.S.S. Collaboration: H. Abdalla, R. Adam, F. Aharonian, F. Ait Benkhali, E.O. Angüner, M. Arakawa, C. Arcaro, C. Armand, H. Ashkar, M. Backes, V. Barbosa Martins, M. Barnard, Y. Becherini, D. Berge, K. Bernlöhr, R. Blackwell, M. Böttcher, C. Boisson, J. Bolmont, S. Bonnefoy, J. Bregeon, M. Breuhaus, F. Brun, P. Brun, M. Bryan, M. Büchele, T. Bulik, T. Bylund, M. Capasso, S. Caroff, A. Carosi, S. Casanova, M. Cerruti, T. Chand, S. Chandra, A. Chen, S. Colafrancesco, M. Curylo, I.D. Davids, C. Deil, J. Devin, P. deWilt, L. Dirson, A. Djannati-Ataï, A. Dmytriiev, A. Donath, V. Doroshenko, L.O'C. Drury, J. Dyks, K. Egberts, G. Emery, J.-P. Ernenwein, S. Eschbach, K. Feijen, S. Fegan, A. Fiasson, G. Fontaine, S. Funk, M. Füßling, S. Gabici, Y.A. Gallant, et al. (165 additional authors not shown)

Comments: In press in A&A. 13 pages, 5 figures. Abstract abridged

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)

Flat-spectrum radio-quasars (FSRQs) are rarely detected at very-high-energies (VHE; E>100 GeV) due to their low-frequency-peaked SEDs. At present, only 6 FSRQs are known to emit VHE photons, representing only 7% of the VHE extragalactic catalog. Following the detection of MeV-GeV gamma-ray flaring activity from the FSRQ PKS 0736+017 (z=0.189) with Fermi, the H.E.S.S. array of Cherenkov telescopes triggered ToO observations on February 18, 2015, with the goal of studying the gamma-ray emission in the VHE band. H.E.S.S. ToO observations were carried out during the nights of February 18, 19, 21, and 24, 2015. Together with Fermi-LAT, the multi-wavelength coverage of the flare includes Swift observations in soft-X-rays and optical/UV, and optical monitoring (photometry and spectro-polarimetry) by the Steward Observatory, the ATOM, the KAIT and the ASAS-SN telescope. VHE emission from PKS 0736+017 was detected with H.E.S.S. during the night of February 19, 2015, only. Fermi data indicate the presence of a gamma-ray flare, peaking at the time of the H.E.S.S. detection, with a flux doubling time-scale of around six hours. The gamma-ray flare was accompanied by at least a 1 mag brightening of the non-thermal optical continuum. No simultaneous observations at longer wavelengths are available for the night of the H.E.S.S. detection. The gamma-ray observations with H.E.S.S. and Fermi are used to put constraints on the location of the gamma-ray emitting region during the flare: it is constrained to be just outside the radius of the broad-line-region with a bulk Lorentz factor $\simeq 20$, or at the level of the radius of the dusty torus with Gamma > 60. PKS 0736+017 is the seventh FSRQ known to emit VHE photons and, at z=0.189, is the nearest so far. The location of the gamma-ray emitting region during the flare can be tightly constrained thanks to opacity, variability, and collimation arguments.

[42]  arXiv:1911.04763 [pdf, other]

Title: Spectral properties and detectability of supermassive stars in protoglobular clusters at high redshift

Authors: F. Martins (1), D. Schaerer (2,3), L. Haemmerlé (2), C. Charbonnel (2,3) ((1) LUPM, CNRS & Montpellier University, (2) Department of Astronomy, Geneva University, (3) IRAP, CNRS & Toulouse University)

Comments: 20 pages, 22 figures. Accepted in Astronomy & Astrophysics

Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA)

Globular clusters contain multiple stellar populations with peculiar chemical compositions. Pollution of the intracluster gas by an early population of fast-evolving stars is the most common scenario for explaining the observations. Stars with masses in excess of 1000 Msun have recently been suggested as potential polluters. We investigate the spectral properties of proto-GCs that would host a supermassive star. Our main goal is to quantify how such a star would affect the integrated light of the cluster, and to study the detectability of such objects. We computed non-LTE atmosphere models for SMS with various combinations of stellar parameters (luminosity, effective temperature, and mass) and metallicities appropriate for GCs, and we predict their emergent spectra. Using these spectra, we calculated the total emission of young proto-GCs with SMS as predicted in a previously reported scenario, and we computed synthetic photometry in UV, optical, and near-IR bands, in particular for the JWST. At an effective temperature of 10000 K, the spectrum of SMSs shows a Balmer break in emission. This feature is due to strong non-LTE effects (implied by the high luminosity) and is not observed in normal stars. The hydrogen lines also show a peculiar behavior, with Balmer lines in emission while higher series lines are in absorption. At 7000 K, the Balmer break shows a strong absorption. At high effective temperatures, the Lyman break is found in emission. Cool and luminous SMSs are found to dominate the integrated spectrum of the cluster, except for the UV range. The predicted magnitudes of these proto-GCs are m_AB~28-30 between 0.7 and 8 um and for redshifts z~4-10, which is detectable with the JWST. The peculiar observational features of cool SMSs imply that they might in principle be detected in color-color diagrams that probe the spectral energy distribution below and above the Balmer break.

[43]  arXiv:1911.04774 [pdf, other]

Title: Unveiling the most luminous Lyman-α emitters in the epoch of reionisation

Authors: Jorryt Matthee, David Sobral

Comments: 5 pages, 3 figures. Proceeding of IAU Symposium #352, 2019, "Uncovering early galaxy evolution in the ALMA and JWST era"

Subjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO)

Distant luminous Lyman-alpha emitters are excellent targets for detailed observations of galaxies in the epoch of reionisation. Spatially resolved observations of these galaxies allow us to simultaneously probe the emission from young stars, partially ionised gas in the interstellar medium and to constrain the properties of the surrounding hydrogen in the circumgalactic medium. We review recent results from (spectroscopic) follow-up studies of the rest-frame UV, Lyman-alpha and [CII] emission in luminous galaxies observed ~500 Myr after the Big Bang with ALMA, HST/WFC3 and VLT/X-SHOOTER. These galaxies likely reside in early ionised bubbles and are complex systems, consisting of multiple well separated and resolved components where traces of metals are already present.

[44]  arXiv:1911.04793 [pdf, other]

Title: HD 117214 debris disk: scattered light images and constraints on the presence of planets

Authors: N. Engler, C. Lazzoni, R. Gratton, H.M. Schmid, G. Chauvin, Q. Kral, J. Milli, N. Pawellek, P. Thébault, A. Boccaletti, M. Bonnefoy, S. Brown, T. Buey, F. Cantalloube, M. Carle, A. Cheetham, S. Desidera, M. Feldt, C. Ginski, D. Gisler, Th. Henning, S. Hunziker, A.M. Lagrange, M. Langlois, D. Mesa, M.R. Meyer, O. Moeller-Nilsson, J. Olofsson, C. Petit, S. Petrus, S.P. Quanz, E. Rickman, E. Stadler, T. Stolker, A. Vigan, F. Wildi, A. Zurlo

Comments: 19 pages

Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)

We performed observations of the Sco-Cen F star HD 117214 aiming at a search for planetary companions and the characterization of the debris disk structure. HD 117214 was observed with the SPHERE subsystems IRDIS, IFS and ZIMPOL at optical and near-IR wavelengths using angular and polarimetric differential imaging techniques. This provided the first images of scattered light from the debris disk with a spatial resolution reaching 25 mas and an inner working angle $< 0.1''$. With the observations with IRDIS and IFS we derive detection limits for substellar companions. The geometrical parameters of the detected disk are constrained by fitting 3D models for the scattering of an optically thin dust disk. Investigating the possible origin of the disk gap, we introduced putative planets therein and modeled the planet-disk and planet-planet dynamical interactions. The obtained planetary architectures are compared with the detection limit curves. The debris disk has an axisymmetric ring structure with a radius of $0.42(\pm 0.01)''$ or $\sim45$ au and an inclination of $71(\pm 2.5)^\circ$ and exhibits a $0.4''$ ($\sim40$ au) wide inner cavity. From the polarimetric data, we derive a polarized flux contrast for the disk of $(F_{\rm pol})_{\rm disk}/F_{\rm \ast}> (3.1 \pm 1.2)\cdot 10^{-4}$ in the RI band. The fractional scattered polarized flux of the disk is eight times smaller than the fractional infrared flux excess. This ratio is similar to the one obtained for the debris disk HIP 79977 indicating that dust radiation properties are not very different between these two disks. Inside the disk cavity we achieve the high sensitivity limits on planetary companions with a mass down to $\sim 4 M_{\rm J}$ at projected radial separations between $0.2''$ and $0.4''$. We can exclude the stellar companions at a radial separation larger than 75 mas from the star.

[45]  arXiv:1911.04800 [pdf, other]

Title: Explaining the Broad-line Region through photoionisation modelling

Authors: Swayamtrupta Panda

Comments: 6 pages, 3 figures, contribution to the Proceedings of the XXXIX Polish Astronomical Society Meeting (09-12 September 2019, Olsztyn, Poland)

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); Astrophysics of Galaxies (astro-ph.GA)

Broad-line regions (BLR) are one of the main components that constitute the phenomenological picture of active galaxies near the vicinity of the accreting supermassive black holes. Both theoretical and observational studies have shown that the BLR is made of dense, ionized gas clumps that have a strong virialized distribution at parsec-scale distances from the nuclei. Using a theoretically motivated photoionized gas model, I constrain the ionisation parameter (U) and cloud density (n$_{\rm{H}}$) as a function of the strength of the FeII emission. Recent observations in the reverberation mapping studies have contested the standard radius-luminosity relation showing increased dispersion in the relation, in particular, after the inclusion of highly accreting quasars. I incorporate the departure coefficient that accounts for this dispersion. This departure term in terms of the dimensionless accretion rate ($\dot{\mathcal{M}}$) and Eddington ratio ($L\mathrm{_{bol}}/L\mathrm{_{Edd}}$), also includes the virial factor that accounts for the BLR geometry. I then combine the fundamental plane relation for the BLR to connect the FeII strength (R$_{\rm{FeII}}$) in terms of U and n$_{\rm{H}}$ using selected values for the shape of the broad H$\beta$ profile.

[46]  arXiv:1911.04803 [pdf, other]

Title: Generating AGN spectra for LSST: First steps

Authors: Swayamtrupta Panda, Bożena Czerny

Comments: 3 pages, 1 figure, contribution to the Proceedings of the XXXIX Polish Astronomical Society Meeting (09-12 September 2019, Olsztyn, Poland)

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); Astrophysics of Galaxies (astro-ph.GA)

In the near future, the arrival of new surveys promises a significant increment in the number of quasars (QSO) at large redshift ranges. This will help to constrain the dark energy models using quasars. The Large Synoptic Survey Telescope (LSST) will cover over 10 million QSO in six photometric bands during its 10-year run. QSO will be monitored and subsequently analysed using the photometric reverberation mapping technique. Oncoming LSST data will decrease the uncertainties in the dark energy determination using reverberating--mapped sources, particularly at high redshifts. We present the first steps in modelling of light curves for H$\beta$ and MgII and discuss the quasar selection in the context of photometric reverberation mapping with LSST. With the onset of the LSST era, we expect a huge rise in the overall quasar counts and redshift range covered ($z\leq7.0$), which will provide a better constraint of AGN properties with cosmological purposes.

[47]  arXiv:1911.04805 [pdf, other]

Title: X-ray study of the double source plane gravitational lens system Eye of Horus observed with XMM-Newton

Authors: Keigo Tanaka, Ayumi Tsuji, Hiroki Akamatsu, J. H. H. Chan, Jean Coupon, Eiichi Egami, Francois Fine, Ryuichi Fujimoto, Yuto Ichinohe, Anton T. Jaelani, Chien-Hsiu Lee, Ikuyuki Mitsuishi, Anupreeta More, Surhud More, Masamune Oguri, Nobuhiro Okabe, Naomi Ota, Cristian E. Rusu, Alessandro Sonnenfeld, Masayuki Tanaka, Shutaro Ueda, Kenneth C. Wong

Comments: 8 pages, 6 figures

Subjects: Astrophysics of Galaxies (astro-ph.GA)

A double source plane (DSP) system is a precious probe for the density profile of distant galaxies and cosmological parameters. However, these measurements could be affected by the surrounding environment of the lens galaxy. Thus, it is important to evaluate the cluster-scale mass for detailed mass modeling. We observed the {\it Eye of Horus}, a DSP system discovered by the Subaru HSC--SSP, with XMM--Newton. We detected two X-ray extended emissions, originating from two clusters, one centered at the {\it Eye of Horus}, and the other located $\sim100$ arcsec northeast to the {\it Eye of Horus}. We determined the dynamical mass assuming hydrostatic equilibrium, and evaluated their contributions to the lens mass interior of the Einstein radius. The contribution of the former cluster is $1.1^{+1.2}_{-0.5}\times10^{12}~M_{\odot}$, which is $21-76\%$ of the total mass within the Einstein radius. The discrepancy is likely due to the complex gravitational structure along the line of sight. On the other hand, the contribution of the latter cluster is only $\sim2\%$ on the {\it Eye of Horus}. Therefore, the influence associated with this cluster can be ignored.

[48]  arXiv:1911.04809 [pdf, other]

Title: Slicing the cool circumgalactic medium along the major-axis of a star-forming galaxy at $z = 0.7$

Authors: S. Lopez, N. Tejos, L. F. Barrientos, C. Ledoux, K. Sharon, A. Katsianis, M. K. Florian, E. Rivera-Thorsen, M. B. Bayliss, H. Dahle, A. Fernandez-Figueroa, M. D. Gladders, M. Gronke, M. Hamel, I. Pessa, J. R. Rigby

Comments: Accepted for publication in MNRAS

Subjects: Astrophysics of Galaxies (astro-ph.GA)

We present spatially-resolved echelle spectroscopy of an intervening MgII-FeII-MgI absorption-line system detected at $z_{\rm abs}=0.73379$ toward the giant gravitational arc PSZ1 G311.65-18.48. The absorbing gas is associated to an inclined disk-like star-forming galaxy, whose major axis is aligned with the two arc-segments reported here. We probe in absorption the galaxy's extended disk continuously, at $\approx 3$ kpc sampling, from its inner region out to $15\times$ the optical radius. We detect strong ($W_0^{2796}>0.3$ \r{A}) coherent absorption along $13$ independent positions at impact parameters $D=0$--$29$ kpc on one side of the galaxy, and no absorption at $D=28$--$57$ kpc on the opposite side (all de-lensed distances at $z_{\rm abs}$). We show that: (1) the gas distribution is anisotropic; (2) $W_0^{2796}$, $W_0^{2600}$, $W_0^{2852}$, and the ratio $W_0^{2600}\!/W_0^{2796}$, all anti-correlate with $D$; (3) the $W_0^{2796}$-$D$ relation is not cuspy and exhibits significantly less scatter than the quasar-absorber statistics; (4) the absorbing gas is co-rotating with the galaxy out to $D \lesssim 20$ kpc, resembling a `flat' rotation curve, but at $D\gtrsim 20$ kpc velocities decline below the expectations from a 3D disk-model extrapolated from the nebular [OII] emission. These signatures constitute unambiguous evidence for rotating extra-planar diffuse gas, possibly also undergoing enriched accretion at its edge. Arguably, we are witnessing some of the long-sought processes of the baryon cycle in a single distant galaxy expected to be representative of such phenomena.

[49]  arXiv:1911.04814 [pdf, other]

Title: New constraints on the HR 8799 planetary system from mid-infrared direct imaging

Authors: D. J. M. Petit dit de la Roche, M. E. van den Ancker, M. Kissler-Patig, V. D. Ivanov, D. Fedele

Comments: Published in MNRAS, 5 pages, 5 figures

Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Instrumentation and Methods for Astrophysics (astro-ph.IM); Solar and Stellar Astrophysics (astro-ph.SR)

Direct imaging is a tried and tested method of detecting exoplanets in the near infrared, but has so far not been extended to longer wavelengths. New data at mid-IR wavelengths (8-20{\mu}m) canprovide additional constraints on planetary atmospheric models. We use the VISIR instrumenton the VLT to detect or set stringent limits on the 8.7{\mu}m flux of the four planets surrounding HR8799, and to search for additional companions. We use a novel circularised PSF subtractiontechnique to reduce the stellar signal and obtain instrument limited background levels andobtain optimal flux limits. The BT SETTL isochrones are then used to determine the resultingmass limits. We find flux limits between 0.7 and 3.3 mJy for the J8.9 flux of the differentplanets at better than5{\sigma}level and derive a new mass limit of 30 MJupfor any objects beyond40 AU. While this work has not detected planets in the HR 8799 system at 8.7{\mu}m, it has foundthat an instrument with the sensitivity of VISIR is sufficient to detect at least 4 known hotplanets around close stars, including\b{eta}Pictoris b (1700 K, 19 pc), with more than5{\sigma}certaintyin 10 hours of observing time in the mid-IR.

[50]  arXiv:1911.04832 [pdf, other]

Title: Thermal and Resonant Emission of Dark Ages Halos in the Rotational Lines of HeH$^{+}$

Authors: Yu. Kulinich, B. Novosyadlyj, V. Shulga, W. Han

Comments: 14 pages, 9 figures, 9 tables

Subjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO)

We present the main features of thermal and resonant emission for one of the first radiating molecules, the helium hydride ion (HeH$^{+}$), from dark ages halos on the stage of the early Universe. Evaluating the optical depth, thermal and resonant brightness temperatures and spectral fluxes of dark ages halos is based on computing the cross-sections and rate coefficients of excitation/de-excitation of the lowest five rotational states of HeH$^{+}$ by inelastic collisions with atomic hydrogen. It was shown that in Dark Ages the collisional excitation/de-excitation by atoms of neutral hydrogen and electrons are competitive, but in the denser regions, e.g. virialized halos, the contribution of collisions with atomic hydrogen is larger. We demonstrate the peak time dependence in the thermal and resonance luminosities evolution of halo in HeH$^{+}$ lines, and the optimization of observations can be made concerning for redshift.

[51]  arXiv:1911.04833 [pdf, other]

Title: Late encounter-events as a source of disks and spiral structures -- Forming second generation disks

Authors: M. Kuffmeier, F. G. Goicovic, C. P. Dullemond

Comments: 14 pages, 7 figures in main text and 2 figures in appendices A and B, accepted for publication in A&A

Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Earth and Planetary Astrophysics (astro-ph.EP); Astrophysics of Galaxies (astro-ph.GA)

Both observations of arc-like structures and luminosity bursts of stars > 1 Myr in age indicate that at least some stars undergo late infall events. We investigate scenarios of replenishing the mass reservoir around a star via capturing and infalling events of cloudlets. We carry out altogether 24 three-dimensional hydrodynamical simulations of cloudlet encounters with a Herbig star of mass 2.5 solar mass using the moving mesh code AREPO. To account for the two possibilities of a star or a cloudlet traveling through the interstellar medium (ISM), we put either the star or the cloudlet at rest with respect to the background gas. For absent cooling in the adiabatic runs, almost none of the cloudlet gas is captured due to high thermal pressure. However, second-generation disks easily form when accounting for cooling of the gas. The disk radii range from several 100 au to about 1000 au and associated arc-like structures up to 10 000 au in length form around the star for runs with and without stellar irradiation. Consistent with angular momentum conservation, the arcs and disks are larger for larger impact parameters. Accounting for turbulence in the cloudlet only mildly changes the model outcome. In the case of the star being at rest with the background gas, the disk formation and mass replenishment process is more pronounced and the associated arc-shaped streamers are longer-lived. The results of our models confirm that late encounter events lead to the formation of transitional disks associated with arc-shaped structures such as observed for AB Aurigae or HD 100546. In addition, we find that second-generation disks and their associated filamentary arms are longer lived (>100 000 yrs) in infall events, when the star is at rest with the background gas.

[52]  arXiv:1911.04891 [pdf, other]

Title: Spectroscopic QUasar Extractor and redshift (z) EstimatorSQUEzE II: Universality of the results

Authors: Ignasi Pérez-Ràfols, Matthew M. Pieri

Comments: 9 pages, 11 figures, 3 tables; submitted to MNRAS

Subjects: Astrophysics of Galaxies (astro-ph.GA)

In this paper we study the universality of the results of SQUEzE, a software package to classify quasar spectra and estimate their redshifts. The code is presented in \cite{Perez-Rafols+2019}. We test the results against changes on signal-to-noise, spectral resolution, wavelength coverage, and quasar brightness. We find that SQUEzE levels of performance are stable to spectra that are 4 times noisier than our standard test sample, BOSS. We also find that the performance remains unchanged if pixels of width 25\AA are considered, and decreases by $\sim2\%$ for pixels of width 100\AA. We see no effect when changing the quasar brightness, and we establish that the blue part (up to 7000\AA) of the spectra is sufficient for the classification. Finally, we study the cases of WEAVE-QSO and DESI spectra, and J-PAS pseudo-spectra, and conclude that SQUEzE will perform similarly on them as it did on BOSS.
{\it Keywords: cosmology: observations - quasar: emission lines - quasar: absorption lines}

[53]  arXiv:1911.04897 [pdf, other]

Title: Spitzer Space Telescope observations of bilobate comet 8P/Tuttle

Authors: O. Groussin, P. L. Lamy, M. S. P. Kelley, I. Toth, L. Jorda, Y. R. Fernández, H. A. Weaver

Comments: Accepted by Astronomy & Astrophysics. 14 pages, 11 figures, 6 tables

Subjects: Earth and Planetary Astrophysics (astro-ph.EP)

Comet 8P/Tuttle is a Nearly Isotropic Comet (NIC), whose physical properties are poorly known and could be different from those of Ecliptic Comets (EC) owing to their different origin. Two independent observations have shown that 8P has a bilobate nucleus. Our goal is to determine the physical properties of the nucleus (size, shape, thermal inertia, albedo) and coma (water and dust) of 8P/Tuttle. We observed the inner coma of 8P with the infrared spectrograph (IRS) and the infrared camera (MIPS) of the Spitzer Space Telescope (SST). We obtained one spectrum (5-40 $\mu$m) on 2 November 2007 and a set of 19 images at 24 $\mu$m on 22-23 June 2008 sampling the nucleus rotational period. The data were interpreted using thermal models for the nucleus and the dust coma, and considering 2 possible shape models of the nucleus derived from respectively Hubble Space Telescope visible and Arecibo radar observations. We favor a nucleus shape model composed of 2 contact spheres with respective radii of 2.7+/-0.1 km and 1.1+/-0.1 km and a pole orientation with RA=285+/-12 deg and DEC=+20+/-5 deg. The nucleus has a thermal inertia in the range 0-100 J/K/m^2/s^0.5 and a R-band geometric albedo of 0.042+/-0.008. The water production rate amounts to 1.1+/-0.2x10^28~molecules/s at 1.6 AU from the Sun pre-perihelion, which corresponds to an active fraction of 9%. At the same distance, the $\epsilon f \rho$ quantity amounts to 310+/-34 cm at 1.6~AU, and reaches 325+/-36 cm at 2.2~AU post-perihelion. The dust grain temperature is estimated to 258+/-10 K, which is 37 K larger than the thermal equilibrium temperature at 1.6 AU. This indicates that the dust grains contributing to the thermal infrared flux have a typical size of 10 $\mu$m. The dust spectrum exhibits broad emissions around 10 $\mu$m (1.5-sigma confidence level) and 18 $\mu$m (5-sigma confidence level) that we attribute to amorphous pyroxene.

[54]  arXiv:1911.04917 [pdf, other]

Title: KISS: a spectrometric imager for millimetre cosmology

Authors: A. Fasano, M. Aguiar, A. Benoit, A. Bideaud, O. Bourrion, M. Calvo, A. Catalano, A. P. de Taoro, G. Garde, A. Gomez, M. F. Gomez Renasco, J. Goupy, C. Hoarau, R. Hoyland, J. F. Macías-Pérez, J. Marpaud, A. Monfardini, G. Pisano, N. Ponthieu, J. A. Rubiño Martín, D. Tourres, C. Tucker, A. Beelen, G. Bres, M. De Petris, P. de Bernardis, G. Lagache, M. Marton, R. Rebolo, S. Roudier

Comments: To appear in the proceedings of the international conference entitled mm Universe @ NIKA2, Grenoble (France), June 2019, EPJ Web of conferences

Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Cosmology and Nongalactic Astrophysics (astro-ph.CO)

Clusters of galaxies are used to map the large-scale structures in the universe and as probe of universe evolution. They can be observed through the Sunyaev-Zeldovich (SZ) effect. At this respect the spectro-imaging at low resolution frequency is an important tool, today, for the study of cluster of galaxies. We have developed KISS (KIDs-Interferometer-Spectrum-Survey), a spectrometric imager dedicated to the secondary anisotropies of the Cosmic Microwave Background (CMB). The multi-frequency approach permits to improve the component separation with respect to predecessor experiments. In this paper, firstly, we provide a description of the scientific context and the state of the art of SZ observations. Secondly, we describe the KISS instrument. Finally, we show preliminary results of the ongoing commissioning campaign.

[55]  arXiv:1911.04934 [pdf, other]

Title: Observed glitches in 8 young pulsars

Authors: Avishek Basu, Bhal Chandra Joshi, M. A. Krishnakumar, Dipankar Bhattacharya, Rana Nandi, Debades Bandhopadhay, Prasanta Char, P. K. Manoharan

Comments: 11 pages, 12 figures, 3 tables; Accepted for publication in MNRAS

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)

The abrupt change in the pulse period of a pulsar is called a pulsar glitch. In this paper, we present eleven pulsar glitches detected using the Ooty Radio Telescope (ORT) and the upgraded Giant Metrewave Radio Telescope (uGMRT) in high cadence timing observations of 8 pulsars. The measured relative amplitude of glitches ($\Delta \nu/\nu$) from our data ranges from $10^{-6}$ to $10^{-9}$. Among these glitches, three are new discoveries, being reported for the first time. We also reanalyze the largest pulsar glitch in the Crab pulsar (PSR J0534+2200) by fitting the ORT data to a new phenomenological model including the slow rise in the post-glitch evolution. We measure an exponential recovery of 30 days after the Vela glitch detected on MJD 57734 with a healing factor $Q=5.8\times 10^{-3}$. Further, we report the largest glitch ($\Delta \nu/\nu = 3147.9 \times 10^{-9}$) so far in PSR J1731$-$4744.

[56]  arXiv:1911.04938 [pdf, other]

Title: Time-resolved photometry of the young dipper RX J1604.3-2130A: Unveiling the structure and mass transport through the innermost disk

Authors: Sicilia-Aguilar, A., Manara, C.F., de Boer, J., Benisty, M., Pinilla, P., Bouvier, J

Comments: A&A in press. 18 pages plus Online material

Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Earth and Planetary Astrophysics (astro-ph.EP)

RX~J1604.3-2130A is a young, dipper-type, variable star in the Upper Scorpius association, suspected to have an inclined inner disk with respect to its face-on outer disk. We study the eclipses to constrain the inner disk properties.We use time-resolved photometry from the Rapid Eye Mount telescope and Kepler2 data to study the multi-wavelength variability, and archival optical and IR data to track accretion, rotation, and changes in disk structure. The observations reveal details of the structure and matter transport through the inner disk. The eclipses show 5d quasi-periodicity, with the phase drifting in time and some periods showing increased/decreased eclipse depth and frequency. Dips are consistent with extinction by slightly processed dust grains in an inclined, irregularly-shaped inner disk locked to the star through two relatively stable accretion structures. The grains are located near the dust sublimation radius ($\sim$0.09 au) at the corotation radius, and can explain the shadows observed in the outer disk. The total mass (gas and dust) required to produce the eclipses and shadows is a few % of a Ceres mass. Such amount of mass is accreted/replenished by accretion in days to weeks, which explains the variability from period to period. Spitzer and WISE variability reveal variations in the dust content in the innermost disk on a few years timescale, which is consistent with small imbalances (compared to the stellar accretion rate) in the matter transport from the outer to the inner disk. A decrease in the accretion rate is observed at the times of less eclipsing variability and low mid-IR fluxes, confirming this picture. The v$sini$=16km/s confirms that the star cannot be aligned with the outer disk, but is likely close to equator-on and to be aligned with the inner disk. This anomalous orientation is a challenge for standard theories of protoplanetary disk formation.

[57]  arXiv:1911.04963 [pdf, other]

Title: ANTARES search for high-energy neutrinos from TeV-emitting blazars, Markarian 421 and 501, in coincidence with HAWC gamma-ray flares

Authors: Mukharbek Organokov, Thierry Pradier

Comments: Presented at the 36th International Cosmic Ray Conference (ICRC 2019), Madison, WI, USA. 8 pages, 4 figures. arXiv admin note: text overlap with arXiv:1809.05777

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)

An updated analysis of a targeted search for high-energy neutrinos from Markarian 421 and Markarian 501 is reported. They are two of the closest and brightest extragalactic sources in the TeV band. In contrast to other types of active galactic nuclei, BL Lacs are characterized by rapid and large-amplitude flux variability. Such radio-loud active galactic nuclei are candidate sources of the observed high-energy cosmic rays. Because their jet is collimated to our line of sight, the hadronic interactions with the surrounding medium can produce an accompanying neutrino and gamma-ray flux. The recent detection of high-energy neutrinos from the direction of TXS 0506+056 motivates a search for high-energy neutrinos from blazars with enhanced gamma-ray activity. These two targeted blazars are subject to long-term monitoring campaigns by the HAWC TeV gamma-ray observatory located in Mexico. This contribution presents the latest results of a search and extends previously presented results to a longer period that covers ANTARES data collected between November 2014 and December 2017. The gamma-ray light curves of each source were used to search for temporally correlated neutrinos, potentially produced in hadronic processes.

[58]  arXiv:1911.04985 [pdf, ps, other]

Title: A Full Implementation of Spectro-Perfectionism for Precise Radial Velocity Exoplanet Detection: A Test Case With the MINERVA Reduction Pipeline

Authors: Matthew A. Cornachione, Adam S. Bolton, Jason D. Eastman, Maurice L. Wilson, Sharon X. Wang, Samson A. Johnson, David H. Sliski, Nate McCrady, Jason T. Wright, Peter Plavchan, John Asher Johnson, Jonathan Horner, Robert A. Wittenmeyer

Comments: 15 pages, 10 figures

Journal-ref: Publications of the Astronomical Society of the Pacific, Volume 131, Number 1006, November 1 2019

Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Earth and Planetary Astrophysics (astro-ph.EP)

We present a computationally tractable implementation of spectro-perfectionism, a method which minimizes error imparted by spectral extraction. We develop our method in conjunction with a full raw reduction pipeline for the MINiature Exoplanet Radial Velocity Array (MINERVA), capable of performing both optimal extraction and spectro-perfectionism. Although spectro-perfectionism remains computationally expensive, our implementation can extract a MINERVA exposure in approximately $30\,\text{min}$. We describe our localized extraction procedure and our approach to point spread function fitting. We compare the performance of both extraction methods on a set of 119 exposures on HD122064, an RV standard star. Both the optimal extraction and spectro-perfectionism pipelines achieve nearly identical RV precision under a six-exposure chronological binning. We discuss the importance of reliable calibration data for point spread function fitting and the potential of spectro-perfectionism for future precise radial velocity exoplanet studies.

[59]  arXiv:1911.04988 [pdf, other]

Title: Magnetic fields from cosmological bulk flows

Authors: J. A. R. Cembranos, A. L. Maroto, H. Villarrubia-Rojo

Comments: 5 pages, 4 figures

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Astrophysics of Galaxies (astro-ph.GA); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Phenomenology (hep-ph)

We explore the possibility that matter bulk flows could generate the required vorticity in the electron-proton-photon plasma to source cosmic magnetic fields through the Harrison mechanism. We analyze the coupled set of perturbed Maxwell and Boltzmann equations for a plasma in which the matter and radiation components exhibit relative bulk motions at the background level. We find that, to first order in cosmological perturbations, bulk flows with velocities compatible with current Planck limits ($\beta<8.5\times 10^{-4}$ at $95\%$ CL) could generate magnetic fields with an amplitude $10^{-21}$ G on 10 kpc comoving scales at the time of completed galaxy formation which could be sufficient to seed a galactic dynamo mechanism.

[60]  arXiv:1911.04989 [pdf, other]

Title: Synergies across the spectrum for particle dark matter indirect detection: how HI intensity mapping meets gamma rays

Authors: E. Pinetti, S. Camera, N. Fornengo, M. Regis

Comments: 22 pages, 12 figures

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Phenomenology (hep-ph)

Neutral hydrogen (HI) intensity mapping traces the large-scale distribution of matter in the Universe and therefore should correlate with the gamma-ray emission originated from particle dark matter annihilation or from active galactic nuclei and star-forming galaxies, since the related processes occur in the same cosmic structures hosting HI. In this paper, we derive the cross-correlation signal between the brightness temperature of the 21-cm line emission of the HI spin-flip transition in the Universe and the unresolved gamma-ray background. Specifically, we derive forecasts for the cross-correlation signal by focussing on the opportunities offered by the combination of the Fermi-Large Area Telescope (LAT) gamma-ray sensitivity with the expectations of the HI intensity mapping measurements from future radio telescopes, for which we concentrate on the Square Kilometre Array (SKA) and MeerKAT, one of its precursors. We find that the combination of MeerKAT with the current Fermi-LAT statistics has the potential to provide a first hint of the cross-correlation signal originated by astrophysical sources, with a signal-to-noise ratio (SNR) of 3.7. With SKA Phase 1 and SKA Phase 2, the SNR is predicted to increase up to 5.7 and 8.2, respectively. The bounds on dark matter properties attainable with SKA combined with the current statistics of Fermi-LAT are predicted to be comparable to those obtained from other techniques able to explore the unresolved components of the gamma-ray background. The enhanced capabilities of SKA Phase 2, combined with a future generation gamma-ray telescope with improved specifications, can allow us to investigate the whole mass window for weakly interacting massive particles up to the TeV scale.

[61]  arXiv:1911.04994 [pdf, ps, other]

Title: The density gradient inside molecular-gas clumps as a booster of their star formation activity

Authors: Genevieve Parmentier

Comments: 10 pages, 7 figures, accepted for publication in ApJ

Subjects: Astrophysics of Galaxies (astro-ph.GA)

Star-forming regions presenting a density gradient experience a higher star formation rate than if they were of uniform density. We refer to the ratio between the star formation rate of a spherical centrally-concentrated gas clump and the star formation rate that this clump would experience if it were of uniform density as the magnification factor $\zeta$. We map $\zeta$ as a function of clump mass, radius, initial volume density profile and star formation time-span. For clumps with a steep density profile (i.e. power-law slope ranging from $-3$ to $-4$, as observed in some high-density regions of Galactic molecular clouds), we find the star formation rate to be at least an order of magnitude higher than its top-hat equivalent. This implies that such clumps experience faster and more efficient star formation than expected based on their mean free-fall time. This also implies that measurements of the star formation efficiency per free-fall time of clumps based on their global properties, namely, mass, mean volume density and star formation rate, present wide fluctuations. These reflect the diversity in the density profile of star-forming clumps, not necessarily variations in the physics of star formation. Steep density profiles inside star-cluster progenitors may be instrumental in the formation of multiple stellar populations, such as those routinely observed in old globular clusters.

[62]  arXiv:1911.05025 [pdf, other]

Title: Gravity-Darkening Analysis of Misaligned Hot Jupiter MASCARA-4 b

Authors: John P. Ahlers, Ethan Kruse, Knicole D. Colon, Patrick Dorval, Geert Jan Talens, Ignas Snellen, Simon Albrecht, Gilles Otten, George Ricker, Roland Vanderspek, David Latham, Sara Seager, Joshua Winn, Jon M. Jenkins, Kari Haworth, Scott Cartwright, Robert Morris, Pam Rowden, Peter Tenenbaum, Eric B. TIng

Comments: Accepted for publication in ApJ

Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)

MASCARA-4 b is a hot Jupiter in a highly-misaligned orbit around a rapidly-rotating A3V star that was observed for 54 days by the Transiting Exoplanet Survey Satellite (\tess). We perform two analyses of MASCARA-4 b using a stellar gravity-darkened model. First, we measure MASCARA-4 b's misaligned orbital configuration by modeling its \tess~photometric light curve. We take advantage of the asymmetry in MASCARA-4 b's transit due to its host star's gravity-darkened surface to measure MASCARA-4 b's true spin-orbit angle to be $104^{\circ+7^\circ}_{-13^\circ}$. We also detect a $\sim4\sigma$ secondary eclipse at $0.491\pm0.007$ orbital phase, proving that the orbit is slightly eccentric. Second, we model MASCARA-4 b's insolation including gravity-darkening and find that the planet's received XUV flux varies by $4$\% throughout its orbit. MASCARA-4 b's short-period, polar orbit suggests that the planet likely underwent dramatic orbital evolution to end up in its present-day configuration and that it receives a varying stellar irradiance that perpetually forces the planet out of thermal equilibrium. These findings make MASCARA-4 b an excellent target for follow-up characterization to better understand orbital evolution and current-day of planets around high-mass stars.

[63]  arXiv:1911.05027 [pdf, ps, other]

Title: TeV-peaked candidate BL Lac objects

Authors: Luigi Costamante

Comments: 9 pages, 2 figures, accepted for publication in MNRAS

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)

BL Lac objects can be extreme in two ways: with their synchrotron emission, peaking beyond 1 keV in their spectral energy distribution, or with their gamma-ray emission, peaking at multi-TeV energies up to and beyond 10-20 TeV, like 1ES 0229+200. This second type of extreme BL Lacs --which we can name "TeV-peaked BL Lacs" is not well explained by the usual synchrotron self-Compton scenarios for BL Lacs. These sources are also important as probes for the intergalactic diffuse infrared background and cosmic magnetic fields, as well as possible sites of production of ultra-high-energy cosmic rays and neutrinos. However, all these studies are hindered by their still very limited number. Here I propose a new, simple criterium to select the best candidates for TeV observations, specifically aimed at this peculiar type of BL Lac objects by combining X-ray, gamma-ray and infrared data. It is based on the observation of a clustering towards a high X-ray to GeV gamma-ray flux ratio, and it does not rely on the radio flux or X-ray spectrum. This makes it suitable to find TeV-peaked sources also with very faint radio emission. Taking advantage of the Fermi all-sky gamma-ray survey applied to the ROMA-BZCAT and Sedentary Survey samples, I produce an initial list of 47 TeV-peaked candidates for observations with present and future air-Cherenkov telescopes.

[64]  arXiv:1911.05039 [pdf, other]

Title: Helium abundance (and $H_0$) in X-COP galaxy clusters

Authors: S. Ettori, V. Ghirardini, D. Eckert

Comments: 7 pages. To appear as proceedings article for the XMM-Newton Workshop "Astrophysics of Hot Plasma in Extended X-ray Sources" held at European Space Astronomy Centre, Madrid, Spain, on 12-14 June 2019

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)

We present the constraints on the helium abundance in 12 X-ray luminous galaxy clusters that have been mapped in their X-ray and Sunyaev-Zeldovich (SZ) signals out to $R_{200}$ for the XMM-Newton Cluster Outskirts Project (X-COP). The unprecedented precision available for the estimate of $H_0$ allows us to investigate how much the reconstructed X-ray and SZ signals are consistent with the expected ratio $x$ between helium and proton densities of 0.08-0.1. We find that a $H_0$ around 70 km/s/Mpc is preferred from our measurements, with lower values of $H_0$ as requested from the Planck collaboration (67 km/s/Mpc) requiring a 34% higher value of $x$.

[65]  arXiv:1911.05048 [pdf, other]

Title: Targeting Earth: CRPropa learns to aim

Authors: Jens Jasche, Arjen van Vliet, Jörg P. Rachen

Comments: Presented at the 36th International Cosmic Ray Conference (ICRC 2019)

Journal-ref: PoS(ICRC2019)447

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)

Realistic predictions for the arrival directions of ultra-high-energy cosmic rays require extensive simulations of UHECR propagation through 3D space, potentially even including cosmological evolution and timing effects. Such 3D or 4D simulations of cosmic-ray propagation suffer from the fact that a relatively small target - the observer sphere - needs to be hit. If particles are ejected in any direction from the source according to the source emission geometry, such simulations are tremendously inefficient. We present here a targeting mechanism which finds an optimal emission geometry to maximize the number of hits while remaining unbiased in the arrival-direction distribution. This can lead to speedups by many of orders of magnitude, depending on the simulation setup. We present the basic mathematics to produce unbiased results from targeted simulations, demonstrate its effectiveness with the simulation package CRPropa 3 for various propagation scenarios, and discuss prospects to include this mechanism as a standard part of CRPropa in the future.

[66]  arXiv:1911.05053 [pdf, other]

Title: The cold circumgalactic environment of MAMMOTH-I: dynamically cold gas in the core of an Enormous Ly-alpha Nebula

Authors: Bjorn Emonts (1), Zheng Cai (2,3), Xavier Prochaska (4,3), Qiong Li (5,6), Matthew Lehnert (7) ((1) NRAO Charlottesville, (2) Tsinghua Univ. Beijing, (3) UCO/Lick Obs., (4) UC Santa Cruz, (5) Dept. Astronomy Peking Univ., (6) Kavli Inst. Peking Univ., (7) IAP Paris)

Comments: 13 pages, 5 figures - ApJ in press

Subjects: Astrophysics of Galaxies (astro-ph.GA)

The MAMMOTH-I Nebula at redshift 2.3 is one of the largest known Ly-alpha nebulae in the Universe, spanning ~440 kpc. Enormous Ly-alpha nebulae like MAMMOTH-I typically trace the densest and most active regions of galaxy formation. Using sensitive low-surface-brightness observations of CO(1-0) with the Very Large Array, we trace the cold molecular gas in the inner 150 kpc of the MAMMOTH-I Nebula. CO is found in four regions that are associated with either galaxies or groups of galaxies that lie inside the nebula. In three of the regions, the CO stretches up to ~30 kpc into the circum-galactic medium (CGM). In the centermost region, the CO has a very low velocity dispersion (FWHM$_{\rm CO}$ ~ 85 km/s), indicating that this gas is dynamically cold. This dynamically cold gas coincides with diffuse restframe optical light in the CGM around a central group of galaxies, as discovered with the Hubble Space Telescope. We argue that this likely represents cooling of settled and enriched gas in the center of MAMMOTH-I. This implies that the dynamically cold gas in the CGM, rather than the obscured AGN, marks the core of the potential well of this Ly-alpha nebula. In total, the CO in the MAMMOTH-I Nebula traces a molecular gas mass of M$_{\rm H2}$ ~ 1.4 ($\alpha_{\rm CO}$/3.6) $\times$ 10$^{11}$ M$_{\odot}$, with roughly 50% of the CO(1-0) emission found in the CGM. Our results add to the increasing evidence that extended reservoirs of molecular gas exist in the CGM of massive high-z galaxies and proto-clusters.

[67]  arXiv:1911.05068 [pdf, other]

Title: The Vanishing & Appearing Sources during a Century of Observations project: I. USNO objects missing in modern sky surveys and follow-up observations of a "missing star"

Authors: Beatriz Villarroel, Johan Soodla, Sébastien Cómeron, Lars Mattsson, Kristiaan Pelckmans, Martín López Corredoira, Kevin Krisciunas, Eduardo Guerras, Oleg Kochukhov, Josefine Bergstedt, Bart Buelens, Rudolf E. Bär, Rubén Cubo, J. Emilio Enriquez, Alok C. Gupta, Iñigo Imaz, Torgny Karlsson, M. Almudena Prieto, Aleksey A. Shlyapnikov, Rafael S. de Souza, Irina B. Vavilova, Martin J. Ward

Comments: SETI meets time domain astronomy. Accepted into the Astronomical Journal

Subjects: Earth and Planetary Astrophysics (astro-ph.EP); High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR)

In this paper we report the current status of a new research program. The primary goal of the "Vanishing & Appearing Sources during a Century of Observations" (VASCO) project is to search for vanishing and appearing sources using existing survey data to find examples of exceptional astrophysical transients. The implications of finding such objects extend from traditional astrophysics fields to the more exotic searches for evidence of technologically advanced civilizations. In this first paper we present new, deeper observations of the tentative candidate discovered by Villarroel et al. (2016). We then perform the first searches for vanishing objects throughout the sky by comparing 600 million objects from the US Naval Observatory Catalogue (USNO) B1.0 down to a limiting magnitude of $\sim 20 - 21$ with the recent Pan-STARRS Data Release-1 (DR1) with a limiting magnitude of $\sim$ 23.4. We find about 150,000 preliminary candidates that do not have any Pan-STARRS counterpart within a 30 arcsec radius. We show that these objects are redder and have larger proper motions than typical USNO objects. We visually examine the images for a subset of about 24,000 candidates, superseding the 2016 study with a sample ten times larger. We find about $\sim$ 100 point sources visible in only one epoch in the red band of the USNO which may be of interest in searches for strong M dwarf flares, high-redshift supernovae or other catagories of unidentified red transients.

Cross-lists for Wed, 13 Nov 19

[68]  arXiv:1911.03305 (cross-list from hep-ph) [pdf, other]

Title: The DNNLikelihood: enhancing likelihood distribution with Deep Learning

Authors: Andrea Coccaro, Maurizio Pierini, Luca Silvestrini, Riccardo Torre

Comments: 44 pages, 17 figures, 8 tables

Subjects: High Energy Physics - Phenomenology (hep-ph); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Experiment (hep-ex); Data Analysis, Statistics and Probability (physics.data-an)

We introduce the DNNLikelihood, a novel framework to easily encode, through Deep Neural Networks (DNN), the full experimental information contained in complicated likelihood functions (LFs). We show how to efficiently parametrise the LF, treated as a multivariate function of parameters and nuisance parameters with high dimensionality, as an interpolating function in the form of a DNN predictor. We do not use any Gaussian approximation or dimensionality reduction, such as marginalisation or profiling over nuisance parameters, so that the full experimental information is retained. The procedure applies to both binned and unbinned LFs, and allows for an efficient distribution to multiple software platforms, e.g. through the framework-independent ONNX model format. The distributed DNNLikelihood can be used for different use cases, such as re-sampling through Markov Chain Monte Carlo techniques, possibly with custom priors, combination with other LFs, when the correlations among parameters are known, and re-interpretation within different statistical approaches, i.e. Bayesian vs frequentist. We discuss the accuracy of our proposal and its relations with other approximation techniques and likelihood distribution frameworks. As an example, we apply our procedure to a pseudo-experiment corresponding to a realistic LHC search for new physics already considered in the literature.

[69]  arXiv:1911.03473 (cross-list from hep-ph) [pdf, other]

Title: Non-equilibrium antineutrinos of primordial nucleosynthesis

Authors: Vlad Yu. Yurchenko, Alexandre V. Ivanchik

Comments: 13 pages, 5 figures

Subjects: High Energy Physics - Phenomenology (hep-ph); Cosmology and Nongalactic Astrophysics (astro-ph.CO)

During the era of primordial nucleosynthesis the background of non-equilibrium antineutrinos is being formed due to decays of neutrons and nuclei of tritium. The spectra of antineutrinos of this background were calculated taking into account the Coulomb interaction between electron and daughter nucleus in $\beta^\text{--}$-decay. The dependence of these spectra on the value of the baryon-to-photon ratio $\eta$ at the period of primordial nucleosynthesis is investigated. The observations of these antineutrinos will allow us to look directly at the very early Universe and nonequilibrium processes taken place before, during, and some time after primordial nucleosynthesis. In any case, this phenomenon is one more aspect in the picture of the standard cosmological model.

[70]  arXiv:1911.04481 (cross-list from nucl-th) [pdf, ps, other]

Title: Comparative study of the direct $α+d$ $\rightarrow$ $^6$Li + $γ$ astrophysical capture reaction in few-body models

Authors: E.M. Tursunov, S.A. Turakulov, A.S. Kadyrov

Comments: 15 pages, 4 figures, 1 table. arXiv admin note: substantial text overlap with arXiv:1903.02403, arXiv:1808.04125

Subjects: Nuclear Theory (nucl-th); Cosmology and Nongalactic Astrophysics (astro-ph.CO); Solar and Stellar Astrophysics (astro-ph.SR)

The astrophysical S factor, the reaction rates of the direct $ \alpha(d,\gamma)^{6}{\rm Li}$ capture reaction, and the primordial abundance of the $^6$Li element are compared within two-body, three-body and combined cluster models. It is shown that the two-body model, based on the exact mass prescription, can not correctly describe the energy dependence of the isospin forbidden E1 S factor and does not reproduce the temperature dependence of the reaction rate from the direct LUNA data. It is found that the isospin forbidden E1 astrophysical S factor is very sensitive to the orthogonalization method of Pauli forbidden states in the three-body model, at the same time the E2 S factor does not depend on the orthogonalization procedure. As a result, the OPP method yields a very good description of the direct data from the LUNA collaboration at low energies, while the SUSY transformation significantly underestimates the LUNA data. On the other hand, both methods show the same energy dependence for the E1 S factor. The best description of the LUNA data for the astrophysical S factor and the reaction rates is obtained within the combined E1(three-body OPP)+E2(two-body) model. It yields a value of $(0.72 \pm 0.01) \times 10^{-14}$ for the $^6$Li/H primordial abundance ratio, consistent with the estimation $(0.80 \pm 0.18) \times 10^{-14}$ of the LUNA collaboration. For the $^6{\rm Li}/^7{\rm Li}$ abundance ratio an estimation $(1.40\pm 0.12)\times 10^{-5}$ is obtained in good agreement with the Standard Model prediction.

[71]  arXiv:1911.04648 (cross-list from hep-ph) [pdf, other]

Title: An Explanation for why the Early Universe was Dominated by the Standard Model and Stable

Authors: Mark P. Hertzberg, Mudit Jain

Comments: 6 pages in double column format, 3 figures

Subjects: High Energy Physics - Phenomenology (hep-ph); Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Theory (hep-th)

Modern developments in quantum gravity suggest that the Standard Model (SM) degrees of freedom are not unique; that a typical low energy effective theory should include a large assortment of hidden sector degrees of freedom. It is therefore puzzling that cosmological constraints from BBN and CMB reveal that the early universe was almost entirely dominated by the SM, when the inflaton $\phi$ could have decayed into many sectors. Furthermore, the SM possesses an instability at high scales that would be catastrophic during or just after inflation, and yet no new physics has been seen to alter this. In this work we propose the following explanation for all of this: the hidden sectors are in fact entirely natural; this means all unprotected masses are pushed up to high scales and project out of the spectrum, while only massless (or protected) degrees of freedom remain, and so the inflaton can only reheat these sectors through higher dimension (and suppressed) operators. On the other hand, the SM possesses a special feature: it includes a light Higgs $H$, presumably for life to exist, and hence it allows a super-renormalizable coupling to the inflaton $\phi\, H^\dagger H$, which allows rapid decay into the SM. We show that this naturally (i) removes the instability in the Higgs potential both during and after inflation, (ii) explains why the SM is dominant in the early universe, (iii) allows dark matter to form in hidden sector/s through subsequent dynamics (or axions, etc), (iv) allows for high reheating and baryogenesis, and (v) accounts for why there so far has been no direct detection of dark matter or new physics beyond the SM.

[72]  arXiv:1911.04703 (cross-list from hep-ph) [pdf, other]

Title: Connecting Light Dirac Neutrinos to a Multi-component Dark Matter Scenario in Gauged $B-L$ Model

Authors: Dibyendu Nanda, Debasish Borah

Comments: 31 pages, 5 figures

Subjects: High Energy Physics - Phenomenology (hep-ph); Cosmology and Nongalactic Astrophysics (astro-ph.CO)

We propose a new gauged $B-L$ extension of the standard model where light neutrinos are of Dirac type, naturally acquiring sub-eV mass after electroweak symmetry breaking. This is realised by choosing a different $B-L$ charge for right handed neutrinos than the usual $-1$ so that the Dirac Yukawa coupling involves an additional neutrinophilic scalar doublet instead of the usual Higgs doublet. The model can be made anomaly free by considering four additional chiral fermions which give rise to two massive Dirac fermions by appropriate choice of singlet scalars. The choice of scalars not only helps in achieving the desired particle mass spectra via spontaneous symmetry breaking, but also leaves a remnant $Z_2 \times Z'_2$ symmetry to stabilise the two dark matter candidates. Apart from this interesting link between Dirac nature of light neutrinos and multi-component dark matter sector, we also find that the dark matter parameter space is constrained mostly by the cosmological upper limit on effective relativistic degrees of freedom $\Delta N_{\rm eff}$ which gets enhanced in this model due to the thermalisation of the light right handed neutrinos by virtue of their sizeable $B-L$ gauge interactions.

[73]  arXiv:1911.04830 (cross-list from gr-qc) [pdf, other]

Title: Thermodynamics of $f(R)$ Theories of Gravity

Authors: C.D. Peralta, S.E. Jorás

Comments: 7 pages, 10 figures

Subjects: General Relativity and Quantum Cosmology (gr-qc); Cosmology and Nongalactic Astrophysics (astro-ph.CO)

This paper starts from a toy model for inflation in a class of modified theories of gravity in the metric formalism. Instead of the standard procedure --- assuming a non-linear Lagrangian $f(R)$ in the Jordan frame --- we start from a simple $\phi^2$ potential in the Einstein frame and investigate the corresponding $f(R)$ in the former picture. The addition of an ad-hoc Cosmological Constant in the Einstein frame leads to a Thermodynamical interpretation of this physical system, which allows further insight on its (meta)stability and evolution.

Replacements for Wed, 13 Nov 19

[74]  arXiv:1312.0237 (replaced) [pdf, ps, other]

Title: Quasi-isotropic expansion for a two-fluid cosmological model containing radiation and string gas

Authors: I.M. Khalatnikov, A.Yu. Kamenshchik, A.A. Starobinsky

Comments: Final version. Published in JETP. arXiv admin note: text overlap with arXiv:gr-qc/0301119

Journal-ref: JETP 129, No. 4, 486-494 (2019) [ZhETF 156, No. 4, 581-584 (2019)]

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)

[75]  arXiv:1810.11465 (replaced) [pdf, other]

Title: Origins of molecular clouds in early-type galaxies

Authors: Iu.V. Babyk, B.R. McNamara, P.D. Tamhane, P.E.J. Nulsen, H.R. Russell, A.C. Edge

Comments: 15 pages, 11 figures, 3 tables; accepted for publication in ApJ; We clarified and increased the discussion of molecular cloud formation in the Introduction and Discussion sections. We discussed three mechanisms of the origin of cold gas in early-type galaxies, including mergers, atmospheric cooling, and stellar ejecta. We pointed out the importance of HI to the picture

Subjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO)

[76]  arXiv:1811.00674 (replaced) [pdf, ps, other]

Title: Pairwise-Correlated Quasars Across the Sky, and in an Earth-Wide Bell Test

Authors: Eric Steinbring

Comments: 12 pages, 11 figures, improved correlation metric developed for comparison; results unchanged

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Quantum Physics (quant-ph)

[77]  arXiv:1811.11125 (replaced) [pdf, ps, other]

Title: Constraining ultra light fermionic dark matter with Milky Way observations

Authors: J. Barranco, A. Bernal, D. Delepine

Comments: 18 pages, 5 figures

Subjects: High Energy Physics - Phenomenology (hep-ph); High Energy Astrophysical Phenomena (astro-ph.HE)

[78]  arXiv:1903.09049 (replaced) [pdf, other]

Title: TARDIS Paper I: A Constrained Reconstruction Approach to Modeling the z~2.5 Cosmic Web Probed by Lyman-alpha Forest Tomography

Authors: Benjamin Horowitz, Khee-Gan Lee, Martin White, Alex Krolewski, Metin Ata

Comments: 18 pages, 14 figures

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Astrophysics of Galaxies (astro-ph.GA)

[79]  arXiv:1904.11534 (replaced) [pdf, other]

Title: X-ray Lightcurves from Realistic Polar Cap Models: Inclined Pulsar Magnetospheres and Multipole Fields

Authors: Will Lockhart, Samuel E. Gralla, Feryal Özel, Dimitrios Psaltis

Comments: 12 pages, 9 figures

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc)

[80]  arXiv:1906.02476 (replaced) [pdf, ps, other]

Title: The impact of inhomogeneous subgrid clumping on cosmic reionization

Authors: Yi Mao (Tsinghua), Jun Koda (Roma), Paul R. Shapiro (U Texas), Ilian T. Iliev (Sussex), Garrelt Mellema (Stockholm), Hyunbae Park (Kavli IPMU), Kyungjin Ahn (Chosun), Michele Bianco (Sussex)

Comments: 23 pages, 16 figures, 4 tables. MNRAS accepted

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Astrophysics of Galaxies (astro-ph.GA)

[81]  arXiv:1906.04205 (replaced) [pdf, other]

Title: POSSIS: predicting spectra, light curves and polarization for multi-dimensional models of supernovae and kilonovae

Authors: Mattia Bulla

Comments: 10 pages, 7 figures; accepted for publication in MNRAS; all modelled spectra are made available at this https URL

Journal-ref: MNRAS 2019 489: 5037-5045

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)

[82]  arXiv:1907.00991 (replaced) [pdf, other]

Title: Neutrino Non-Standard Interactions: A Status Report

Authors: P. S. Bhupal Dev, K. S. Babu, Peter B. Denton, Pedro A. N. Machado, Carlos A. Argüelles, Joshua L. Barrow, Sabya Sachi Chatterjee, Mu-Chun Chen, André de Gouvêa, Bhaskar Dutta, Dorival Gonçalves, Tao Han, Matheus Hostert, Sudip Jana, Kevin J. Kelly, Shirley Weishi Li, Ivan Martinez-Soler, Poonam Mehta, Irina Mocioiu, Yuber F. Perez-Gonzalez, Jordi Salvado, Ian M. Shoemaker, Michele Tammaro, Anil Thapa, Jessica Turner, Xun-Jie Xu

Comments: 104 pages; minor revision

Subjects: High Energy Physics - Phenomenology (hep-ph); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics - Experiment (hep-ex); Nuclear Theory (nucl-th)

[83]  arXiv:1907.05344 (replaced) [pdf, other]

Title: Dawn of the dark: unified dark sectors and the EDGES Cosmic Dawn 21-cm signal

Authors: Weiqiang Yang, Supriya Pan, Sunny Vagnozzi, Eleonora Di Valentino, David F. Mota, Salvatore Capozziello

Comments: 18 pages, 3 Tables, 2 figures; version accepted for publication in JCAP

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc)

[84]  arXiv:1907.09481 (replaced) [pdf, other]

Title: The Southern Stellar Stream Spectroscopic Survey (${S}^5$): Overview, Target Selection, Data Reduction, Validation, and Early Science

Authors: T. S. Li, S. E. Koposov, D. B. Zucker, G. F. Lewis, K. Kuehn, J. D. Simpson, A. P. Ji, N. Shipp, Y.-Y. Mao, M. Geha, A. B. Pace, A. D. Mackey, S. Allam, D. L. Tucker, G. S. Da Costa, D. Erkal, J. D. Simon, J. R. Mould, S. L. Martell, Z. Wan, G. M. De Silva, K. Bechtol, E. Balbinot, V. Belokurov, J. Bland-Hawthorn, A. R. Casey, L. Cullinane, A. Drlica-Wagner, S. Sharma, A. K. Vivas, R. H. Wechsler, B. Yanny

Comments: 25 pages, 14 figures (1 in appendix), 3 tables (1 in appendix). Published on MNRAS. See also paper from Shipp et al. 2019, which measures the proper motion of the DES streams

Subjects: Astrophysics of Galaxies (astro-ph.GA)

[85]  arXiv:1907.13059 (replaced) [pdf, other]

Title: Superconducting nanowires as high-rate photon detectors in strong magnetic fields

Authors: T. Polakovic, W.R. Armstrong, V. Yefremenko, J.E. Pearson, K. Hafidi, G. Karapetrov, Z.-E. Meziani, V. Novosad

Subjects: Instrumentation and Detectors (physics.ins-det); Instrumentation and Methods for Astrophysics (astro-ph.IM); Superconductivity (cond-mat.supr-con); High Energy Physics - Experiment (hep-ex)

[86]  arXiv:1908.00906 (replaced) [pdf, other]

Title: Bayesian inflationary reconstructions from Planck 2018 data

Authors: Will J. Handley, Anthony N. Lasenby, Hiranya V. Peiris, Michael P. Hobson

Comments: 25 Pages, 15 Figures

Journal-ref: Phys. Rev. D 100, 103511, 11 November 2019

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Instrumentation and Methods for Astrophysics (astro-ph.IM); General Relativity and Quantum Cosmology (gr-qc)

[87]  arXiv:1908.02700 (replaced) [pdf, other]

Title: Multiscatter capture of superheavy dark matter by Pop. III stars

Authors: Cosmin Ilie, Saiyang Zhang

Comments: Added an appendix with details regarding the SHDM annihilations

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)

[88]  arXiv:1908.04682 (replaced) [pdf, other]

Title: CMB-GAN: Fast Simulations of Cosmic Microwave background anisotropy maps using Deep Learning

Authors: Amit Mishra, Pranath Reddy, Rahul Nigam

Comments: 9 pages, cosmic microwave background radiation, deep learning, generative adversarial network. arXiv admin note: text overlap with arXiv:1903.12253

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Machine Learning (cs.LG); Image and Video Processing (eess.IV)

[89]  arXiv:1908.07146 (replaced) [pdf, other]

Title: Atomic Layer Deposition Niobium Nitride Films for High-Q Resonators

Authors: Calder Sheagren, Peter Barry, Erik Shirokoff, Qing Yang Tang

Comments: Submitted to JLTP, LTD18 special edition

Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Applied Physics (physics.app-ph)

[90]  arXiv:1908.11258 (replaced) [pdf, other]

Title: Rotating neutron stars with non-barotropic thermal profile

Authors: Giovanni Camelio, Tim Dietrich, Miguel Marques, Stephan Rosswog

Comments: 18 pages, 3 appendices, 2 tables, 9 figures. Accepted by PRD

Subjects: General Relativity and Quantum Cosmology (gr-qc); High Energy Astrophysical Phenomena (astro-ph.HE)

[91]  arXiv:1909.06378 (replaced) [pdf, other]

Title: Asteroseismic constraints on the cosmic-time variation of the gravitational constant from an ancient main-sequence star

Authors: Earl Patrick Bellinger, Jørgen Christensen-Dalsgaard

Comments: 5 pages, 3 figures, accepted for publication in The Astrophysical Journal Letters

Subjects: Solar and Stellar Astrophysics (astro-ph.SR); General Relativity and Quantum Cosmology (gr-qc)

[92]  arXiv:1909.09817 (replaced) [pdf, other]

Title: Extending the Epoch of Reionization window with apt Foreground and Instrument modeling

Authors: Dinesh V. Raut

Comments: 11 pages, submitted to ApJ

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)

[93]  arXiv:1909.12318 (replaced) [pdf, ps, other]

Title: J0453+1559: a neutron star-white dwarf binary from a thermonuclear electron-capture supernova?

Authors: Thomas M. Tauris (Aarhus Uni.), H.-Thomas Janka (MPA, Garching)

Comments: ApJL, accepted for publication (6 pages, 4 figures)

Subjects: Solar and Stellar Astrophysics (astro-ph.SR); High Energy Astrophysical Phenomena (astro-ph.HE)

[94]  arXiv:1909.13300 (replaced) [pdf, other]

Title: Modeling Mg II During Solar Flares. II. Non-equilibrium Effects

Authors: Graham S. Kerr, Mats Carlsson, Joel C.Allred

Comments: 12 pages, 13 figures, accepted in the Astrophysical Journal

Subjects: Solar and Stellar Astrophysics (astro-ph.SR)

[95]  arXiv:1910.01643 (replaced) [pdf, ps, other]

Title: Low-frequency variability in massive stars: Core generation or surface phenomenon?

Authors: Daniel Lecoanet, Matteo Cantiello, Eliot Quataert, Louis-Alexandre Couston, Keaton J. Burns, Benjamin J. S. Pope, Adam S. Jermyn, Benjamin Favier, Michael Le Bars

Comments: Accepted to ApJL. Supplementary information available at: this http URL

Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Instrumentation and Methods for Astrophysics (astro-ph.IM); Fluid Dynamics (physics.flu-dyn)

[96]  arXiv:1910.04652 (replaced) [pdf, other]

Title: Low dust emissivities and radial variations in the envelopes of Class 0 protostars: a signature of early grain growth?

Authors: Maud Galametz, Anaelle J. Maury, Valeska Valdivia, Leonardo Testi, Arnaud Belloche, Philippe Andre

Comments: 17 pages, 11 figures, accepted for publication in A&A

Subjects: Astrophysics of Galaxies (astro-ph.GA)

[97]  arXiv:1911.01431 (replaced) [pdf, other]

Title: Differential Rotation in Convective Envelopes: Constraints from Eclipsing Binaries

Authors: Adam S. Jermyn, Jamie Tayar, Jim Fuller

Comments: 19 pages, published in MNRAS. Corrected typos and cases where solar/anti-solar were swapped

Subjects: Solar and Stellar Astrophysics (astro-ph.SR)

[98]  arXiv:1911.01852 (replaced) [pdf, ps, other]

Title: Active Galactic Nuclei with Ultra-fast Outflows Monitoring Project: The Broad-line Region of Mrk 79 as a Disk Wind

Authors: Kai-Xing Lu, Jin-Ming Bai, Zhi-Xiang Zhang, Pu Du, Chen Hu, Minjin Kim, Jian-Min Wang, Luis C. Ho, Yan-Rong Li, Wei-Hao Bian, Ye-Fei Yuan, Ming Xiao, Hai-Cheng Feng, Jian-Guo Wang, Liang Xu, Xu Ding, Xiao-Guang Yu, Yu-Xin Xin, Kai Ye, Chuan-Jun Wang, Bao-Li Lun, Ju-Jia Zhang, Xi-Liang Zhang, Kai-Fan Ji, Yu-Feng Fan, Liang Chang

Comments: 21 pages, 16 figures, accepted for publication in ApJ

Subjects: Astrophysics of Galaxies (astro-ph.GA)

[99]  arXiv:1911.02979 (replaced) [pdf, other]

Title: Estimating trajectories of meteors: an observational Monte Carlo approach -- I. Theory

Authors: Denis Vida, Peter S. Gural, Peter G. Brown, Margaret Campbell-Brown, Paul Wiegert

Comments: Accepted for publication in MNRAS

Subjects: Earth and Planetary Astrophysics (astro-ph.EP)

[100]  arXiv:1911.03702 (replaced) [pdf, ps, other]

Title: The Initial Mass Function in the Extended Ultraviolet Disk of M83

Authors: Sarah M. Bruzzese (1), David A. Thilker (2), Gerhardt Meurer (1), Luciana Bianchi (2), Adam B. Watts (1), Annette M. N. Ferguson (3), Armando Gil de Paz (4), Barry F. Madore (5,6), D. Christopher Martin (7), R. Michael Rich (8) ((1) ICRAR, The University of Western Australia, (2) The Johns Hopkins University, (3) IfA, Eduinburgh, (4) Universidad Complutense de Madrid, (5) University of Chicago, (6) Observatories of the Carnegie Institution for Science, (7) California Institute of Technology, (8) UCLA)

Comments: MNRAS accepted. 28 pages, 7 Tables, 19 Figures. See published article or contact third author for paper with figures at full resolution. (V2: small error in metadata corrected)

Subjects: Astrophysics of Galaxies (astro-ph.GA)

[101]  arXiv:1911.04095 (replaced) [pdf, other]

Title: Tracing the co-evolution path of super massive black holes and spheroids with AKARI-selected ultra-luminous IR galaxies at intermediate redshifts

Authors: Xiao-Yang Chen, Masayuki Akiyama, Kohei Ichikawa, Hirofumi Noda, Yoshiki Toba, Issei Yamamura, Toshihiro Kawaguchi, Abdurrouf, Mitsuru Kokubo

Comments: 30 pages, 39 figures, 7 tables; added references for section 5.4

Subjects: Astrophysics of Galaxies (astro-ph.GA)

[102]  arXiv:1911.04465 (replaced) [pdf, other]

Title: The Origin of Massive Stars: The Inertial-Inflow Model

Authors: Paolo Padoan, Liubin Pan, Mika Juvela, Troels Haugbølle, Åke Nordlund

Comments: 31 pages, 27 figures, Submitted to ApJ

Subjects: Astrophysics of Galaxies (astro-ph.GA); Solar and Stellar Astrophysics (astro-ph.SR)

• New submissions
• Cross-lists
• Replacements