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New submissions for Thu, 9 Apr 20
- [1] arXiv:2004.03600 [pdf, other]
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Title: Erosion driven size-redistribution of protoplanetary disk solids and the onset of streaming Instability and Pebble AccretionComments: Comments are welcomeSubjects: Earth and Planetary Astrophysics (astro-ph.EP)
The formation of the first planetesimals and the final growth of planetary cores likely relies on the abundance of small pebbles. The efficiencies of both the streaming instability (SI) process, suggested to catalyze the early growth of planetesimals, and the pebble-accretion process, suggested to accelerate the growth of planetary cores, depend on the sizes of solids residing in the disk. In particular, these processes were found to be sensitive to size-distribution of solids, and efficient planetesimal formation and growth through these channels require a limited pebble size-distribution. Here we show that aeolian-erosion, a process that efficiently grinds down boulders into a mono-sized distribution of pebbles, provides a natural upper cut-off for the maximal pebble sizes. We find the dependence of the critical solids size cut-off on the radial separation, disk age, turbulence strength, and the grain-size composition of the boulders in the disk. This size cut-off shapes the size distribution of small pebbles and thereby helps catalyze the early onset of SI formation of planetesimals, and the later core accretion growth through pebble accretion.
- [2] arXiv:2004.03601 [pdf, other]
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Title: Updated Parameters and a New Transmission Spectrum of HD 97658bAuthors: Xueying Guo, Ian J. M. Crossfield, Diana Dragomir, Molly R. Kosiarek, Joshua Lothringer, Thomas Mikal-Evans, Lee Rosenthal, Bjorn Benneke, Heather A. Knutson, Paul A. Dalba, Eliza M. R. Kempton, Gregory W. Henry, P. R. McCullough, Travis Barman, Sarah Blunt, Ashley Chontos, Jonathan Fortney, Benjamin J. Fulton, Lea Hirsch, Andrew W. Howard, Howard Isaacson, Jaymie Matthews, Teo Mocnik, Caroline Morley, Erik A. Petigura, Lauren M. WeissComments: Accepted to AJ. 29 pages, 21 figures, 11 tables, 2 machine-readable tables (system RVs and TSM values)Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)
Recent years have seen increasing interest in the characterization of sub-Neptune sized planets because of their prevalence in the Galaxy, contrasted with their absence in our solar system. HD 97658 is one of the brightest stars hosting a planet of this kind, and we present the transmission spectrum of this planet by combining four HST transits, twelve Spitzer/IRAC transits, and eight MOST transits of this system. Our transmission spectrum has higher signal to noise ratio than that from previous works, and the result suggests that the slight increase in transit depth from wavelength 1.1 to 1.7 microns reported in previous works on the transmission spectrum of this planet is likely systematic. Nonetheless, our atmospheric modeling results are not conclusive as no model provides an excellent match to our data. Nonetheless we find that atmospheres with high C/O ratios (C/O >~ 0.8) and metallicities of >~ 100x solar metallicity are favored. We combine the mid-transit times from all the new Spitzer and MOST observations and obtain an updated orbital period of P=9.489295 +/- 0.000005 d, with a best-fit transit time center at T_0 = 2456361.80690 +/- 0.00038 (BJD). No transit timing variations are found in this system. We also present new measurements of the stellar rotation period (34 +/- 2 d) and stellar activity cycle (9.6 yr) of the host star HD 97658. Finally, we calculate and rank the Transmission Spectroscopy Metric of all confirmed planets cooler than 1000 K and with sizes between 1 and 4 R_Earth. We find that at least a third of small planets cooler than 1000 K can be well characterized using JWST, and of those, HD 97658b is ranked fifth, meaning it remains a high-priority target for atmospheric characterization.
- [3] arXiv:2004.03603 [pdf, other]
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Title: Cosmic archaeology with massive stellar black hole binariesComments: MNRAS Letters, in pressSubjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc)
The existence of massive stellar black hole binaries (MBHBs), with primary black hole (BH) masses $\ge 31 \, M_\odot$, was proven by the detection of the gravitational wave (GW) event GW150914 during the first LIGO/Virgo observing run (O1), and successively confirmed by seven additional GW signals discovered in the O1 and O2 data. By adopting the galaxy formation model \texttt{GAMESH} coupled with binary population synthesis (BPS) calculations, here we investigate the origin of these MBHBs by selecting simulated binaries compatible in mass and coalescence redshifts. We find that their cosmic birth rates peak in the redshift range $6.5 \leq z \leq 10$, regardless of the adopted BPS. These MBHBs are then old systems forming in low-metallicity ($Z \sim [0.01-0.1] \, Z_{\odot}$), low-stellar-mass galaxies, before the end of cosmic reionization, i.e. significantly beyond the peak of cosmic star formation. GW signals generated by coalescing MBHBs open up new possibilities to probe the nature of stellar populations in remote galaxies, at present too faint to be detected by available electromagnetic facilities.
- [4] arXiv:2004.03606 [pdf, other]
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Title: On the significance of relativistically hot pairs in the jets of FR II radio galaxiesComments: 7 pages, 1 figure, resubmitted to the MNRAS after the first reviewSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
The energetic composition of radio lobes in the FR II galaxies $-$ estimated by comparing their radio luminosities with the powers required to inflate cavities in the external medium $-$ seems to exclude the possibility of their energetic domination by protons. Furthermore, if the jets were dominated by the kinetic energy of cold protons, it would be difficult to efficiently accelerate leptons in the jets' terminal shocks. This suggests that the jets powering the lobes are dominated by pairs not only in number but also in enthalpy. Such a possibility is confronted against the constraints imposed by the jet formation scenarios, and by the properties of jets on parsec and kiloparsec scales. We find a lower limit on the pair content from the energetic dominance of leptons over protons in the radio lobes, which exceeds the estimate of $n_e/n_p \sim 20$ indicated by models of the blazar zones and of the radio cores. This allows us to establish that the average energy of protons in the jet co-moving frame is $<2m_pc^2$, and to estimate the number fluxes of protons and $e^{+}e^{-}$ pairs. The required proton flux is achievable, if the jet carries away about $1\%$ of the accreting matter. Loading the jets by pairs can be achieved by pair creation using soft gamma-ray photons from the accretion disk corona, provided that about $2-3\%$ of the disk radiation extends beyond $1\;{\rm MeV}$. Finally, we discuss possible dissipative mechanisms which may keep the jets dominated by relativistically hot pairs.
- [5] arXiv:2004.03608 [pdf, other]
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Title: Below the subgrid: uncertainties in supernova input rates drive qualitative differences in simulations of galaxy evolutionComments: MNRAS submitted, comments welcome!Subjects: Astrophysics of Galaxies (astro-ph.GA)
Feedback from core collapse supernovae (SNe), the final stage of evolution of the most massive stars, has long been a key element in simulations of galaxy formation. In this paper, we examine how simplifying assumptions made in approximating the SN rates along with underlying physical uncertainty in those rates can lead to large variations in the overall evolution of simulated Milky Way-like galaxies. We find that the clustering of star formation is strongly impacted by the delay between star formation and SN feedback. In addition, the choice to use a realistic delay time distribution or instantaneous injection for SN can have a significant impact on the galaxy. These effects appear even when identical sub-grid models are used for coupling SN energy and momentum, and the total SN energy budget is kept constant. In addition, we show that the uncertain minimum SN progenitor mass has a significant impact on the SN energy budget and injection timescale, and can completely change the overall evolution of the galaxy. These underlying uncertainties mean that despite advances in the sub-grid modelling of SN feedback, there are still serious difficulties in constraining the effects of SN feedback. This complicates the task of comparing different simulations to each other, as well as comparing simulations to observations. We conclude by providing practical limits on the parameters of subgrid models for SN feedback, which bound the uncertainty arising from SN progenitor physics for future predictions from galaxy simulations.
- [6] arXiv:2004.03611 [pdf, other]
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Title: Modelling a bright z = 6 galaxy at the faint end of the AGN luminosity functionComments: 10+1 pages, 10+1 figures. Accepted for publications in MNRAS. Key figures: 5 and 10Subjects: Astrophysics of Galaxies (astro-ph.GA)
Recent deep surveys have unravelled a population of faint active galactic nuclei (AGN) in the high redshift Universe, leading to various discussions on their nature and their role during the Epoch of Reionization. We use cosmological radiation-hydrodynamics simulations of a bright galaxy at z = 6 ($M_\star \gtrsim 10^{10} M_\odot$) hosting an actively growing super-massive black hole to study the properties of these objects. In particular, we study how the black hole and the galaxy co-evolve and what is the relative contribution of the AGN and of the stellar populations to the luminosity budget of the system. We find that the feedback from the AGN has no strong effect on the properties of the galaxy, and does not increase the total ionizing luminosity of the host. The average escape fraction of our galaxy is around $f_{\rm esc} \sim 5\%$. While our galaxy would be selected as an AGN in deep X-ray surveys, most of the UV luminosity is originating from stellar populations. This confirms that there is a transition in the galaxy population from star forming galaxies to quasar hosts, with bright Lyman-Break Galaxies (LBGs) with $M_{\rm UV}$ around -22 falling in the overlap region. Our results also suggest that faint AGN do not contribute significantly to reionizing the Universe.
- [7] arXiv:2004.03612 [pdf, other]
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Title: Outside the Wall: Hydrodynamics of Type I Supernovae Interacting with a Partially Swept-Up Circumstellar MediumComments: 17 pages, 13 figures, accepted to ApJSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
Explaining the observed diversity of supernovae (SNe) and the physics of explosion requires knowledge of their progenitor stars, which can be obtained by constraining the circumstellar medium (CSM). Models of the SN ejecta colliding with CSM are necessary to infer the structure of the CSM and tie it back to a progenitor model. Recent SNe I revealed CSM concentrated at a distance $r\sim10^16$ cm, for which models of SN interaction are extremely limited. In this paper, we assume the concentrated region is a "wall" representing swept-up material, and unswept material lies outside the wall. We simulate one-dimensional hydrodynamics of SNe Ia & Ib impacting 300 unique CSM configurations using RT1D, which captures the Rayleigh-Taylor instability. We find that the density ratio between the wall and ejecta -- denoted $A_0$ or "wall height" -- is key, and higher walls deviate more from self-similar evolution. Functional fits accounting for $A_0$ are presented for the forward shock radius evolution. We show that higher walls have more degeneracy between CSM properties in the deceleration parameter, slower shocks, deeper-probing reverse shocks, slower shocked ejecta, less ejecta mass than CSM in the shock, and more mixing of ejecta into the CSM at early times. We analyze observations of SN 2014C (Type Ib) and suggest that it had a moderately high wall ($10 < A_0 < 200$) and wind-like outer CSM. We also postulate an alternate interpretation for the radio data of SN 2014C, that the radio rise occurs in the wind rather than the wall. Finally, we find that hydrodynamic measurements at very late times cannot distinguish the presence of a wall, except perhaps as an anomalously wide shock region.
- [8] arXiv:2004.03615 [pdf, other]
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Title: High-resolution, 3D radiative transfer modelling. II. The early-type spiral galaxy M81Authors: Sam Verstocken, Angelos Nersesian, Maarten Baes, Sébastien Viaene, Simone Bianchi, Viviana Casasola, Christopher J. R. Clark, Jonathan I. Davies, Ilse De Looze, Pieter De Vis, Wouter Dobbels, FrédÉric Galliano, Anthony P. Jones, Suzanne C. Madden, Aleksandr V. Mosenkov, Ana Trčka, Emmanuel M. XilourisComments: 23 pages, 16 figures, accepted for publication in A&ASubjects: Astrophysics of Galaxies (astro-ph.GA)
Interstellar dust absorbs stellar light very efficiently and thus shapes the energetic output of galaxies. Studying the impact of different stellar populations on the dust heating remains hard because it requires decoupling the relative geometry of stars and dust, and involves complex processes as scattering and non-local dust heating. We aim to constrain the relative distribution of dust and stellar populations in the spiral galaxy M81 and create a realistic model of the radiation field that describes the observations. Investigating the dust-starlight interaction on local scales, we want to quantify the contribution of young and old stellar populations to the dust heating. We aim to standardise the setup and model selection of such inverse radiative transfer simulations so this can be used for comparable modelling of other nearby galaxies. We present a semi-automated radiative transfer modelling pipeline that implements the necessary steps such as the geometric model construction and the normalisation of the components through an optimisation routine. We use the Monte Carlo radiative transfer code SKIRT to calculate a self-consistent, panchromatic model of the interstellar radiation field. By looking at different stellar populations independently, we can quantify to what extent different stellar age populations contribute to the dust heating. Our method takes into account the effects of non-local heating. We obtain a realistic 3D radiative transfer model of the face-on galaxy M81. We find that only 50.2\% of the dust heating can be attributed to young stellar populations. We confirm a tight correlation between the specific star formation rate and the heating fraction by young stellar populations, both in sky projection and in 3D, also found for radiative transfer models of M31 and M51. We conclude that... (abridged)
- [9] arXiv:2004.03616 [pdf, other]
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Title: High-resolution, 3D radiative transfer modelling III. The DustPedia barred galaxiesAuthors: Angelos Nersesian (1,2,3), Sam Verstocken (3), Sebastien Viaene (3,4), Maarten Baes (3), Emmanuel M. Xilouris (1), Simone Bianchi (5), Viviana Casasola (5,6), Christopher J. R. Clark (7), Jonathan I. Davies (8), Ilse De Looze (3,9), Pieter De Vis (8), Wouter Dobbels (3), Jacopo Fritz (10), Maud Galametz (11), Frederic Galliano (11), Anthony P. Jones (12), Suzanne C. Madden (11), Aleksandr V. Mosenkov (13,14), Ana Trcka (3), Nathalie Ysard (12)Subjects: Astrophysics of Galaxies (astro-ph.GA)
Context: Dust in late-type galaxies in the local Universe is responsible for absorbing approximately one third of the energy emitted by stars. It is often assumed that dust heating is mainly attributable to the absorption of UV and optical photons emitted by the youngest (<= 100 Myr) stars. Consequently, thermal re-emission by dust at FIR wavelengths is often linked to the star-formation activity of a galaxy. However, several studies argue that the contribution to dust heating by much older stars might be more significant. Advances in radiation transfer (RT) simulations finally allow us to actually quantify the heating mechanisms of diffuse dust by the stellar radiation field.
Aims: As one of the main goals in the DustPedia project, we have constructed detailed 3D stellar and dust RT models for nearby galaxies. We analyse the contribution of the different stellar populations to the dust heating in four face-on barred galaxies: NGC1365, M83, M95, and M100. We aim to quantify the fraction directly related to young stars, both globally and on local scales, and to assess the influence of the bar on the heating fraction.
Results: We derive global attenuation laws for each galaxy and confirm that galaxies of high sSFR have shallower attenuation curves and weaker UV bumps. On average, 36.5% of the bolometric luminosity is absorbed by dust. We report a clear effect of the bar structure on the radial profiles of the dust-heating fraction by the young stars, and the dust temperature. We find that the young stars are the main contributors to the dust heating, donating, on average ~59% of their luminosity to this purpose throughout the galaxy. This dust-heating fraction drops to ~53% in the bar region and ~38% in the bulge region where the old stars are the dominant contributors to the dust heating. We also find a strong link between the heating fraction by the young stars and the sSFR. - [10] arXiv:2004.03629 [pdf, other]
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Title: Fast Calculation of Nonlinear Redshift-space Galaxy Power Spectrum Including Selection BiasComments: 26 pages, 8 figures, submitted to PRDSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
We present a fast implementation of the next-to-leading order (1-loop) redshift-space galaxy power spectrum by using FFTlog-based methods. [V. Desjacques, D. Jeong, and F. Schmidt, JCAP 1812 (12), 035] have shown that the 1-loop galaxy power spectrum in redshift space can be computed with 28 independent loop integrals with 22 bias parameters. Analytical calculation of the angular part of the loop integrals leaves the radial part in the form of a spherical Bessel transformation that is ready to be integrated numerically by using the FFTLog transformation. We find that the original 28 loop integrals can be solved with a total of 85 unique FFTLog transformations, yet leading to a few orders of magnitude speed up over traditional multi-dimensional integration. The code used in this work is publicly available at https://github.com/JosephTomlinson/GeneralBiasPk
- [11] arXiv:2004.03631 [pdf, other]
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Title: Detectability of Life Using Oxygen on Pelagic Planets and Water WorldsAuthors: Donald M Glaser, Hilairy Ellen Hartnett, Steven J. Desch, Cayman T. Unterborn, Ariel Anbar, Steffen Buessecker, Theresa Fisher, Steven Glaser, Stephen R. Kane, Carey M. Lisse, Camerian Millsaps, Susanne Neuer, Joseph G. ORourke, Nuno Santos, Sara Imari Walker, Mikhail ZolotovSubjects: Earth and Planetary Astrophysics (astro-ph.EP)
The search for life on exoplanets is one of the grand scientific challenges of our time. The strategy to date has been to find (e.g., through transit surveys like Kepler) Earth-like exoplanets in their stars habitable zone, then use transmission spectroscopy to measure biosignature gases, especially oxygen, in the planets atmospheres (e.g., using JWST, the James Webb Space Telescope). Already there are more such planets than can be observed by JWST, and missions like the Transiting Exoplanet Survey Satellite and others will find more. A better understanding of the geochemical cycles relevant to biosignature gases is needed, to prioritize targets for costly follow-up observations and to help design future missions. We define a Detectability Index to quantify the likelihood that a biosignature gas could be assigned a biological vs. non-biological origin. We apply this index to the case of oxygen gas, O2, on Earth-like planets with varying water contents. We demonstrate that on Earth-like exoplanets with 0.2 weight percent (wt%) water (i.e., no exposed continents) a reduced flux of bioessential phosphorus limits the export of photosynthetically produced atmospheric O2 to levels indistinguishable from geophysical production by photolysis of water plus hydrogen escape. Higher water contents >1wt% that lead to high-pressure ice mantles further slow phosphorus cycling. Paradoxically, the maximum water content allowing use of O2 as a biosignature, 0.2wt%, is consistent with no water based on mass and radius. Thus, the utility of an O2 biosignature likely requires the direct detection of both water and land on a planet.
- [12] arXiv:2004.03668 [pdf, other]
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Title: Star Cluster Formation in Orion AAuthors: Wanggi Lim, Fumitaka Nakamura, Benjamin Wu, Thomas G. Bisbas, Jonathan C. Tan, Edward Chambers, John Bally, Shuo Kong, Peregrine McGehee, Dariusz C. Lis, Volker Ossenkopf-Okada, Álvaro Sánchez-MongeComments: 16 pages, 11 figures, 4 tables, accepted for publication in PASJSubjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA)
We introduce new analysis methods for studying the star cluster formation processes in Orion A, especially examining the scenario of a cloud-cloud collision. We utilize the CARMA-NRO Orion survey $^{13}$CO (1-0) data to compare molecular gas to the properties of YSOs from the SDSS III IN-SYNC survey. We show that the increase of $v_{\rm 13CO} - v_{\rm YSO}$ and $\Sigma$ scatter o older YSOs can be signals of cloud-cloud collision. SOFIA-upGREAT 158$\mu$m [CII] archival data toward the northern part of Orion A are also compared to the $^{13}$CO data to test whether the position and velocity offsets between the emission from these two transitions resemble those predicted by a cloud-cloud collision model. We find that the northern part of Orion A, including regions ONC-OMC-1, OMC-2, OMC-3 and OMC-4, shows qualitative agreements with the cloud-cloud collision scenario, while in one of the southern regions, NGC1999, there is no indication of such a process in causing the birth of new stars. On the other hand, another southern cluster, L1641N, shows slight tendencies of cloud-cloud collision. Overall, our results support the cloud-cloud collision process as being an important mechanism for star cluster formation in Orion A.
- [13] arXiv:2004.03676 [pdf, other]
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Title: Gamma-Ray and X-Ray Observations of the Periodic-Repeater FRB 180916 During Active PhasesAuthors: M. Tavani, F. Verrecchia, C. Casentini, M. Perri, A. Ursi, L. Pacciani, C. Pittori, A. Bulgarelli, G. Piano, M. Pilia, G. Bernardi, A. Addis, L.A. Antonelli, A. Argan, L. Baroncelli, P. Caraveo, P.W. Cattaneo, A. Chen, E. Costa, G. Di Persio, I. Donnarumma, Y. Evangelista, M. Feroci, A. Ferrari, V. Fioretti, F. Lazzarotto, F. Longo, A. Morselli, F. Paoletti, N. Parmiggiani, A. Trois, S. Vercellone, G. Naldi, G. Pupillo, G. Bianchi, S. PuccettiComments: Accepted for publication by the Astrophysical Journal Letters on April 5, 2020Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)
FRB 180916 is a most intriguing source at 150 Mpc distance capable of producing repeating fast radio bursts with a periodic 16.35 day temporal pattern. We report on the X-ray and $\gamma$-ray observations of FRB 180916 obtained by AGILE and Swift. We focused on the recurrent 5-day time intervals of active radio bursting and present results obtained on Feb. 3 - 8; Feb. 25; Mar. 5 - 10; Mar. 22 - 28, 2020 during a multiwavelength campaign involving high-energy and radio observations. We also searched for temporal coincidences at millisecond timescales between all known radio bursts of FRB 180916 and X-ray and MeV events detectable by AGILE. We do not detect any simultaneous event or any extended X-ray and $\gamma$-ray emission on timescales of hours/days/weeks. Our cumulative X-ray (0.3-10 keV) flux upper limit of $5 \times\,10^{-14} \rm \, erg \, cm^{-2} s^{-1}$ (obtained during 5-day active intervals) translates into an isotropic luminosity upper limit of $L_{X,UL} \sim 1.5 \times\, 10^{41} \rm erg \, s^{-1}$. Observations above 100 MeV over a many-year timescale provide an average luminosity upper limit one order of magnitude larger. These results provide the so-far most stringent limits on high-energy emission from FRB 180916 and constrain the dissipation of magnetic energy from a magnetar-like source of radius $R_m$, internal magnetic field $B_m$ and dissipation timescale $\tau_d$ to satisfy the relation $R_{m,6}^3 B_{m,16}^2 \tau_{d,8}^{-1} \lesssim 1$, where $R_{m,6}$ is $R_m$ in units of $10^6$ cm, $B_{m,16}$ is $B_m$ in units of $10^{16}$ G, and $\tau_{d,8}$ in units of $10^8$ s.
- [14] arXiv:2004.03679 [pdf, other]
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Title: Solar disk center shows scattering polarization in the Sr~{\sc i} 4607~Å~lineAuthors: Franziska Zeuner, Rafael Manso Sainz, Alex Feller, Michiel van Noort, Sami K. Solanki, Francisco A. Iglesias, Kevin Reardon, Valentín Martínez PilletComments: 15 pages , 6 figuresSubjects: Solar and Stellar Astrophysics (astro-ph.SR)
Magnetic fields in turbulent, convective high-$\beta$ plasma naturally develop highly tangled and complex topologies---the solar photosphere being the paradigmatic example. These fields are mostly undetectable by standard diagnostic techniques with finite spatio-temporal resolution due to cancellations of Zeeman polarization signals. Observations of resonance scattering polarization have been considered to overcome these problems. But up to now, observations of scattering polarization lack the necessary combination of high sensitivity and high spatial resolution in order to directly infer the turbulent magnetic structure at the resolution limit of solar telescopes. Here, we report the detection of clear spatial structuring of scattering polarization in a magnetically quiet solar region at disk center in the Sr~{\sc i} 4607~\AA spectral line on granular scales, confirming theoretical expectations. We find that the linear polarization presents a strong spatial correlation with the local quadrupole of the radiation field. The result indicates that polarization survives the dynamic and turbulent magnetic environment of the middle photosphere and is thereby usable for spatially-resolved Hanle observations. This is an important step towards the long-sought goal of directly observing turbulent solar magnetic fields at the resolution limit and investigating their spatial structure.
- [15] arXiv:2004.03689 [pdf, other]
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Title: On the settling of small grains in dusty discs: analysis and formulasComments: 13 pages, 4 figures, accepted for publication in MNRASSubjects: Earth and Planetary Astrophysics (astro-ph.EP)
Instruments achieve sharper and finer observations of micron-in-size dust grains in the top layers of young stellar discs. To provide accurate models, we revisit the theory of dust settling for small grains, when gas stratification, dust inertia and finite correlation times for the turbulence should be handled simultaneously. We start from a balance of forces and derive distributions at steady-state. Asymptotic expansions require caution since limits do not commute. In particular, non-physical bumpy distributions appear when turbulence is purely diffusive. This excludes very short correlation times for real discs, as predicted by numerical simulations.
- [16] arXiv:2004.03701 [pdf, other]
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Title: Optimal periodicity searching: Revisiting the Fast Folding Algorithm for large-scale pulsar surveysComments: Submitted to MNRAS, 19 pages, 9 figuresSubjects: Instrumentation and Methods for Astrophysics (astro-ph.IM)
The Fast Folding Algorithm (FFA) is a phase-coherent search technique for periodic signals. It has rarely been used in radio pulsar searches, having been historically supplanted by the less computationally expensive Fast Fourier Transform (FFT) with incoherent harmonic summing (IHS). Here we derive from first principles that an FFA search closely approaches the theoretical optimum sensitivity to all periodic signals; it is analytically shown to be significantly more sensitive than the standard FFT+IHS method, regardless of pulse period and duty cycle. A portion of the pulsar phase space has thus been systematically under-explored for decades; pulsar surveys aiming to fully sample the pulsar population should include an FFA search as part of their data analysis. We have developed an FFA software package, riptide, fast enough to process radio observations on a large scale; riptide has already discovered sources undetectable using existing FFT+IHS implementations. Our sensitivity comparison between search techniques also shows that a more realistic radiometer equation is needed, which includes an additional term: the search efficiency. We derive the theoretical efficiencies of both the FFA and the FFT+IHS methods and discuss how excluding this term has consequences for pulsar population synthesis studies.
- [17] arXiv:2004.03748 [pdf, other]
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Title: Probing the Temperature Structure of Optically Thick Disks Using Polarized Emission of Aligned GrainsAuthors: Zhe-Yu Daniel Lin, Zhi-Yun Li, Haifeng Yang, Leslie Looney, Chin-Fei Lee, Ian Stephens, Shih-Ping LaiComments: Published in MNRAS, 17 pages, 9 figuresJournal-ref: Monthly Notices of the Royal Astronomical Society, Volume 493, Issue 4, April 2020, Pages 4868-4883Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Earth and Planetary Astrophysics (astro-ph.EP); Astrophysics of Galaxies (astro-ph.GA)
Polarized continuum emission from aligned grains in disks around young stellar objects can be used to probe the magnetic field, radiation anisotropy, or drift between dust and gas, depending on whether the non-spherical grains are aligned magnetically, radiatively or mechanically. We show that it can also be used to probe another key disk property -- the temperature gradient -- along sight lines that are optically thick, independent of the grain alignment mechanism. We first illustrate the technique analytically using a simple 1D slab model, which yields an approximate formula that relates the polarization fraction to the temperature gradient with respect to the optical depth tau at the tau=1 surface. The formula is then validated using models of stellar irradiated disks with and without accretion heating. The promises and challenges of the technique are illustrated with a number of Class 0 and I disks with ALMA dust polarization data, including NGC 1333 IRAS4A1, IRAS 16293B, BHB 07-11, L1527, HH 212 and HH 111. We find, in particular, that the sight lines passing through the near-side of a highly inclined disk trace different temperature gradient directions than those through the far-side, which can lead to a polarization orientation on the near-side that is orthogonal to that on the far-side, and that the HH 111 disk may be such a case. Our technique for probing the disk temperature gradient through dust polarization can complement other methods, particularly those using molecular lines.
- [18] arXiv:2004.03772 [pdf, other]
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Title: Modelling the asymmetry of the halo cross-correlation function with relativistic effects at quasi-linear scalesComments: 22 pages, 9 figuresSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc)
The observed galaxy distribution via galaxy redshift surveys appears distorted due to redshift-space distortions (RSD). While one dominant contribution to RSD comes from the Doppler effect induced by the peculiar velocity of galaxies, the relativistic effects, including the gravitational redshift effect, are recently recognized to give small but important contributions. Such contributions lead to an asymmetric galaxy clustering along the line of sight, and produce non-vanishing odd multipoles when cross-correlating between different biased objects. However, non-zero odd multipoles are also generated by the Doppler effect beyond the distant-observer approximation, known as the wide-angle effect, and at quasi-linear scales, the interplay between wide-angle and relativistic effects becomes significant. In this paper, based on the formalism developed by Taruya et al., we present a quasi-linear model of the cross-correlation function taking a proper account of both the wide-angle and gravitational redshift effects, as one of the major relativistic effects. Our quasi-linear predictions of the dipole agree well with simulations even at the scales below $20\,h^{-1}\,$Mpc, where non-perturbative contributions from the halo potential play an important role, flipping the sign of the dipole amplitude. When increasing the bias difference and redshift, the scale where the sign flip happens is shifted to a larger scale. We derive a simple approximate formula to quantitatively account for the behaviors of the sign flip.
- [19] arXiv:2004.03777 [pdf, other]
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Title: Mid-infrared Variability of gamma-ray emitting blazarsComments: 13 pages, 13 figuresSubjects: Astrophysics of Galaxies (astro-ph.GA)
Using data from the Wide-field Infrared Survey Explorer we studied the mid infrared 3.4 $\mu$m (W1-band) and 4.6 $\mu$m (W2-band) flux variability of $\gamma$-ray emitting blazars. Our sample consists of 460 flat spectrum radio quasars (FSRQs) and 575 BL Lacertae (BL Lac) objects. On intra-day timescales, the median amplitude of variability ($\sigma_{m}$) for FSRQs is 0.04$^{+0.03}_{-0.02}$ mag and 0.05$^{+0.03}_{-0.02}$ mag in W1 and W2 bands. For BL Lacs we found median $\sigma_{m}$ in W1(W2) bands of 0.04$^{+0.01}_{-0.02}$ (0.04$^{+0.02}_{-0.02}$) mag. On long timescales, for FSRQs we found a median $\sigma_{m}$ of 0.44$^{+0.28}_{-0.27}$ mag and 0.45$^{+0.27}_{-0.27}$ mag in W1 and W2 bands, while for BL Lacs the median values are 0.21$^{+0.18}_{-0.12}$ mag and 0.22$^{+0.18}_{-0.11}$ mag in W1 and W2 bands. From statistical tests, we found FSRQs to show larger $\sigma_m$ than BL Lacs on both intra-day and long timescales. Among blazars, low synchrotron peaked (LSP) sources showed larger $\sigma_m$ compared to intermediate synchrotron peaked (ISP) and high synchrotron peaked (HSP) sources.The larger $\sigma_{m}$ seen in FSRQs relative to BL Lacs on both intra-day and long timescales could be due to them having the most powerful relativistic jets and/or their mid infrared band coinciding with the peak of the electron energy distribution. BL Lacs have low power jets and the observational window too traces the emission from low energy electrons, thereby leading to low $\sigma_{m}$. In both FSRQs and BL Lacs predominantly a bluer when brighter behaviour was observed. No correlation is found between $\sigma_m$ and black hole mass.
- [20] arXiv:2004.03790 [pdf, other]
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Title: Initiation and Early Kinematic Evolution of Solar EruptionsComments: Accepted for publication in ApJ; 24 pages, 12 figures, 3 tablesSubjects: Solar and Stellar Astrophysics (astro-ph.SR); Plasma Physics (physics.plasm-ph); Space Physics (physics.space-ph)
We investigate the initiation and early evolution of 12 solar eruptions, including six active region hot channel and six quiescent filament eruptions, which were well observed by the \textsl{Solar Dynamics Observatory}, as well as by the \textsl{Solar TErrestrial RElations Observatory} for the latter. The sample includes one failed eruption and 11 coronal mass ejections, with velocities ranging from 493 to 2140~km~s$^{-1}$. A detailed analysis of the eruption kinematics yields the following main results. (1) The early evolution of all events consists of a slow-rise phase followed by a main-acceleration phase, the height-time profiles of which differ markedly and can be best fit, respectively, by a linear and an exponential function. This indicates that different physical processes dominate in these phases, which is at variance with models that involve a single process. (2) The kinematic evolution of the eruptions tends to be synchronized with the flare light curve in both phases. The synchronization is often but not always close. A delayed onset of the impulsive flare phase is found in the majority of the filament eruptions (5 out of 6). This delay, and its trend to be larger for slower eruptions, favor ideal MHD instability models. (3) The average decay index at the onset heights of the main acceleration is close to the threshold of the torus instability for both groups of events (although based on a tentative coronal field model for the hot channels), suggesting that this instability initiates and possibly drives the main acceleration.
- [21] arXiv:2004.03792 [pdf, ps, other]
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Title: Accretion Flow Evolution of a New Black Hole Candidate MAXI J1348-630 During the 2019 OutburstAuthors: Arghajit Jana, Dipak Debnath, Debjit Chatterjee, Kaushik Chatterjee, Sandip Kumar Chakrabarti, Sachindra Naik, Riya Bhowmick, Neeraj KumariComments: 15 Pages, 6 Figures, 2 Tables; Submitted to ApJSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
Galactic black hole candidate MAXI~J1348-630 was recently discovered by MAXI and Swift/BAT satellites during its first outburst in 2019 January which continued for ~4 months. We study the spectral and timing properties of the source in detail. The combined 1-150 keV Swift/XRT, Swift/BAT and MAXI/GSC spectra are investigated with the two component advective flow (TCAF) solution. Physical flow parameters of TCAF, such as Keplerian disk accretion rate, sub-Keplerian halo accretion rate, the shock location and the shock compression ratio are estimated from our spectral fits. Based on the variation of flux in soft and hard X-ray ranges, the hardness ratio, TCAF model fitted accretion rates and accretion rate ratio (ARR), we show how the sources evolved through four spectral states viz. hard, hard-intermediate, soft-intermediate and soft states in rising and declining states. Low-frequency quasi-periodic oscillations (QPO) are observed in two observations during the rising phase of the outburst. From the spectral analysis, we estimate the mass of the black hole to be $9.1^{+1.8}_{-1.2}$ $M_{\odot}$. We also find that the viscous timescale in this outburst is ~ 3.5 days.
- [22] arXiv:2004.03817 [pdf, other]
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Title: NIHAO-XXIII: Dark Matter density shaped by Black Hole feedbackAuthors: Andrea V. Macciò (NYUAD, MPIA), Samuele Crespi (NYUAD), Marvin Blank (NYUAD), Xi Kang (PMO, ZJU)Comments: 5 pages, 4 figures, accepted for publication in MNRAS LettersSubjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
We present a systematic analysis of the reaction of dark matter distribution to galaxy formation across more than eight orders of magnitude in stellar mass. We extend the previous work presented in the NIHAO-IV paper (Tollet et al.) by adding 46 new high resolution simulations of massive galaxies performed with the inclusion of Black Hole feedback. We show that outflows generated by the AGN are able to partially counteract the dark matter contraction due to the large central stellar component in massive haloes. The net effect is to relax the central dark matter distribution that moves to a less cuspy density profiles at halo masses larger than $\approx 3 \times 10^{12}$ M$_{\odot}$. The scatter around the mean value of the density profile slope ($\alpha$) is fairly constant ($\Delta\alpha \approx 0.3$), with the exception of galaxies with halo masses around $10^{12}$ M$_{\odot}$, at the transition from stellar to AGN feedback dominated systems, where the scatter increases by almost a factor three. We provide useful fitting formulas for the slope of the dark matter density profiles at few percent of the virial radius for the whole stellar mass range: $10^5-10^{12}$ M$_{\odot}$ ($2 \times 10^9-5 \times 10^{13}$ M$_{\odot}$ in halo mass).
- [23] arXiv:2004.03824 [pdf, other]
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Title: X-ray variability analysis of a large series of XMM-Newton + NuSTAR observations of NGC 3227Comments: Accepted for publication in MNRAS; 19 pages, 13 figures, 4 tablesSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
We present a series of X-ray variability results from a long XMM-Newton + NuSTAR campaign on the bright, variable AGN NGC 3227. We present an analysis of the lightcurves, showing that the source displays typically softer-when-brighter behaviour, although also undergoes significant spectral hardening during one observation which we interpret as due to an occultation event by a cloud of absorbing gas. We spectrally decompose the data and show that the bulk of the variability is continuum-driven and, through rms variability analysis, strongly enhanced in the soft band. We show that the source largely conforms to linear rms-flux behaviour and we compute X-ray power spectra, detecting moderate evidence for a bend in the power spectrum, consistent with existing scaling relations. Additionally, we compute X-ray Fourier time lags using both the XMM-Newton and - through maximum-likelihood methods - NuSTAR data, revealing a strong low-frequency hard lag and evidence for a soft lag at higher frequencies, which we discuss in terms of reverberation models.
- [24] arXiv:2004.03855 [pdf, other]
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Title: Comparison of the shape and temporal evolution of even and odd solar cyclesComments: 10 pages, 13 figuresJournal-ref: A&A 636, A11 (2020)Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Applications (stat.AP)
Results. The PCA confirms the existence of the Gnevyshev gap (GG) for solar cycles at about 40% from the start of the cycle. The temporal evolution of sunspot area data for even cycles shows that the GG exists at least at the 95% confidence level for all sizes of sunspots. On the other hand, the GG is shorter and statistically insignificant for the odd cycles of aerial sunspot data. Furthermore, the analysis of sunspot area sizes for even and odd cycles of SC12-SC23 shows that the greatest difference is at 4.2-4.6 years, where even cycles have a far smaller total area than odd cycles. The average area of the individual sunspots of even cycles is also smaller in this interval. The statistical analysis of the temporal evolution shows that northern sunspot groups maximise earlier than southern groups for even cycles, but are concurrent for odd cycles. Furthermore, the temporal distributions of odd cycles are slightly more leptokurtic than distributions of even cycles. The skewnesses are 0.37 and 0.49 and the kurtoses 2.79 and 2.94 for even and odd cycles, respectively. The correlation coefficient between skewness and kurtosis for even cycles is 0.69, and for odd cycles, it is 0.90. Conclusions. The separate PCAs for even and odd sunspot cycles show that odd cycles are more inhomogeneous than even cycles, especially in GSN data. Even cycles, however, have two anomalous cycles: SC4 and SC6. According to the analysis of the sunspot area size data, the GG is more distinct in even than odd cycles. We also present another Waldmeier-type rule, that is, we find a correlation between skewness and kurtosis of the sunspot group cycles.
- [25] arXiv:2004.03872 [pdf, other]
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Title: Exploring extensions to the standard cosmological model and the impact of baryons on small scalesAuthors: Sam G. Stafford, Shaun T. Brown, Ian G. McCarthy, Andreea S. Font, Andrew Robertson, Robert Poole-MckenzieComments: 22 pages, 12 figures, submitted to MNRASSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Astrophysics of Galaxies (astro-ph.GA)
It has been claimed that the standard model of cosmology (LCDM) cannot easily account for a number of observations on relatively small scales, motivating extensions to the standard model. Here we introduce a new suite of cosmological simulations that systematically explores three plausible extensions: warm dark matter, self-interacting dark matter, and a running of the scalar spectral index of density fluctuations. Current observational constraints are used to specify the additional parameters that come with these extensions. We examine a large range of observable metrics on small scales, including the halo mass function, density and circular velocity profiles, the abundance of satellite subhaloes, and halo concentrations. For any given metric, significant degeneracies can be present between the extensions. In detail, however, the different extensions have quantitatively distinct mass and radial dependencies, suggesting that a multi-probe approach over a range of scales can be used to break the degeneracies. We also demonstrate that the relative effects on the radial density profiles in the different extensions (compared to the standard model) are converged down to significantly smaller radii than are the absolute profiles. We compare the derived cosmological trends with the impact of baryonic physics using the EAGLE and ARTEMIS simulations. Significant degeneracies are also present between baryonic physics and cosmological variations (with both having similar magnitude effects on some observables). Given the inherent uncertainties both in the modelling of galaxy formation physics and extensions to LCDM, a systematic and simultaneous exploration of both is strongly warranted.
- [26] arXiv:2004.03918 [pdf, ps, other]
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Title: Sky Quality Meter and satellite correlation for the night cloud cover analysis at astronomical sitesAuthors: S. Cavazzani, S. Ortolani, A. Bertolo, R. Binotto, P. Fiorentin, G. Carraro, I. Saviane, V. ZitelliJournal-ref: MNRAS Volume 493, Issue 2, April 2020, Pages 2463Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM)
The analysis of the night cloud cover is very important for astronomical observation in real time, considering a typical observation time of about 15 minutes, and to have a statistics of the night cloud cover. In this paper we use the SQM (Sky Quality Meter) for high resolution temporal analysis of the La Silla and Asiago (Ekar observatory) sky: 3 and 5 minutes respectively. We investigate the annual temporal evolution of the natural contributions of the sky in a site not influenced by artificial light at night (ALAN) and one highly influenced respectively. We also make a correlation between GOES and AQUA satellites data and ground-based SQM data to confirm a relationship between the SQM data and cloud cover. We develop an algorithm that allows the use of the SQM for night cloud detection and we reach a correlation of 97.2\% at La Silla and 94.6\% at Asiago with the nighttime cloud cover detected by the GOES and AQUA satellites. Our algorithm also classifies the photometric (PN) and spectroscopic nights (SN). We measure 59.1\% PN and 21.7\% SN for a total percentage of clear nights of 80.8\% at La Silla in 2018. The respective Ekar observatory values are 31.1\% PN, 24.0\% SN and 55.1\% of total clear nights time. Application to the SQM network would involve the development of long-term statistics and big data forecasting models, for site testing and real-time astronomical observation.
- [27] arXiv:2004.03931 [pdf, other]
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Title: Global Mapping of the Surface Composition on an Exo-Earth using Color VariabilityAuthors: Hajime KawaharaComments: 20 pages, 14 figures, accepted for publication in ApJ. The code is available online at this https URLSubjects: Earth and Planetary Astrophysics (astro-ph.EP); Instrumentation and Methods for Astrophysics (astro-ph.IM)
Photometric variation of a directly imaged planet contains information on both the geography and spectra of the planetary surface. We propose a novel technique that disentangles the spatial and spectral information from the multi-band reflected light curve. This will enable us to compose a two-dimensional map of the surface composition of a planet with no prior assumption on the individual spectra, except for the number of independent surface components. We solve the unified inverse problem of the spin-orbit tomography and spectral unmixing by generalizing the non-negative matrix factorization (NMF) using a simplex volume minimization method. We evaluated our method on a toy cloudless Earth and observed that the new method could accurately retrieve the geography and unmix spectral components. Furthermore, our method is also applied to the real-color variability of the Earth as observed by Deep Space Climate Observatory (DSCOVR). The retrieved map explicitly depicts the actual geography of the Earth and unmixed spectra capture features of the ocean, continents, and clouds. It should be noted that, the two unmixed spectra consisting of the reproduced continents resemble those of soil and vegetation.
- [28] arXiv:2004.03936 [pdf, other]
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Title: HCF (HREXI Calibration Facility): Mapping out sub-pixel level responses from high resolution Cadmium Zinc Telluride (CZT) imaging X-ray detectorsComments: 27 pages, 19 figures, Accepted for publication in the Journal of Astronomical Telescopes, Instruments, and Systems (SPIE)Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Instrumentation and Detectors (physics.ins-det)
The High Resolution Energetic X-Ray Imager (HREXI) CZT detector development program at Harvard is aimed at developing tiled arrays of finely pixelated CZT detectors for use in wide-field coded aperture 3-200 keV X-ray telescopes. A pixel size of $\simeq$ 600 $\mu m$ has already been achieved in the ProtoEXIST2 (P2) detector plane with CZT read out by the NuSTAR ASIC. This paves the way for even smaller 300 $\mu m$ pixels in the next generation HREXI detectors. This article describes a new HREXI calibration facility (HCF) which enables a high resolution sub-pixel level (100 $\mu m$) 2D scan of a 256 $cm^2$ tiled array of 2 $\times$ 2 cm CZT detectors illuminated by a bright X-ray AmpTek Mini-X tube source at timescales of around a day. HCF is a significant improvement from the previous apparatus used for scanning these detectors which took $\simeq$ 3 weeks to complete a 1D scan of a similar detector plane. Moreover, HCF has the capability to scan a large tiled array of CZT detectors ($32cm \times 32cm$) at 100 $\mu m$ resolution in the 10 - 50 keV energy range which was not possible previously. This paper describes the design, construction, and implementation of HCF for the calibration of the P2 detector plane.
- [29] arXiv:2004.03940 [pdf, ps, other]
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Title: A distinct magnetic property of the inner penumbral boundary III. Analysis of simulated sunspotsAuthors: Jan Jurcak, Markus Schmassmann, Matthias Rempel, Nazaret Bello Gonzalez, Rolf SchlichenmaierSubjects: Solar and Stellar Astrophysics (astro-ph.SR)
The analyses of sunspot observations revealed a fundamental magnetic property of the umbral boundary, the invariance of the vertical component of the magnetic field. We aim to analyse the magnetic properties of the umbra-penumbra boundary in simulated sunspots and thus assess their similarity to observed sunspots. Also, we aim to investigate the role of plasma $\beta$ and the ratio of kinetic to magnetic energy in simulated sunspots on the convective motions. We use a set of non-grey simulation runs of sunspots with the MURaM code. These data are used to synthesise the Stokes profiles that are then degraded to the Hinode spectropolarimeter-like observations. Then, the data are treated like real Hinode observations of a sunspot and magnetic properties at the umbral boundaries are determined. Simulations with potential field extrapolation produce a realistic magnetic field configuration on their umbral boundaries. Two simulations with potential field upper boundary, but different subsurface magnetic field structures, differ significantly in the extent of their penumbrae. Increasing the penumbra width by forcing more horizontal magnetic fields at the upper boundary results in magnetic properties that are not consistent with observations. This implies that the size of the penumbra is given by the subsurface structure of the magnetic field. None of the sunspot simulations is consistent with observed properties of the magnetic field and direction of the Evershed flow at the same time. Strong outward directed Evershed flows are only found in setups with artificially enhanced horizontal component of the magnetic field at the top boundary that are not consistent with the observed magnetic field properties at the UP boundary. We want to stress out that the `photospheric' boundary of simulated sunspots is defined by a magnetic field strength of equipartition field value.
- [30] arXiv:2004.03941 [pdf, other]
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Title: Global Mapping of an Exo-Earth using Sparse ModelingComments: 17 pages, 9 figures, accepted for publication in the Astrophysical JournalSubjects: Earth and Planetary Astrophysics (astro-ph.EP); Instrumentation and Methods for Astrophysics (astro-ph.IM)
We develop a new retrieval scheme for obtaining two-dimensional surface maps of exoplanets from scattered light curves. In our scheme, the combination of the L1-norm and Total Squared Variation, which is one of the techniques used in sparse modeling, is adopted to find the optimal map. We apply the new method to simulated scattered light curves of the Earth, and find that the new method provides a better spatial resolution of the reconstructed map than those using Tikhonov regularization. We also apply the new method to observed scattered light curves of the Earth obtained during the two-year DSCOVR/EPIC observations presented by Fan et al. (2019). The method with Tikhonov regularization enables us to resolve North America, Africa, Eurasia, and Antarctica. In addition to that, the sparse modeling identifies South America and Australia, although it fails to find the Antarctica maybe due to low observational weights on the poles. Besides, the proposed method is capable of retrieving maps from noise injected light curves of a hypothetical Earth-like exoplanet at 10 pc with noise level expected from coronagraphic images from the planned telescope, the Habitable Exoplanet Observatory (HabEx). We find that the sparse modeling resolves Australia, Afro-Eurasia, North America, and South America using 2-year observation with a time interval of one month. Our study shows that the combination of sparse modeling and multi-epoch observation with 1 day per month can be used to identify main features of an Earth analog in future direct imaging missions such as HabEx and the Large UV/Optical/IR Surveyor (LUVOIR).
- [31] arXiv:2004.03957 [pdf, other]
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Title: Continuum polarization reverberation mapping of AGNsComments: Accepted for publication in A&ASubjects: Astrophysics of Galaxies (astro-ph.GA); High Energy Astrophysical Phenomena (astro-ph.HE)
The determination of the size and geometry of the broad line region (BLR) in active galactic nuclei is one of the major ingredients for determining the mass of the accreting black hole. This can be done by determining the delay between the optical continuum and the flux reprocessed by the BLR, in particular via the emission lines. We propose here that the delay between polarized and unpolarized light can also be used in much the same way to constrain the size of the BLR; we check that meaningful results can be expected from observations using this technique. We use our code STOKES for performing polarized radiative transfer simulations. We determine the response of the central source environment (broad line region, dust torus, polar wind) to fluctuations of the central source that are randomly generated; we then calculate the cross correlation between the simulated polarized flux and the total flux to estimate the time delay that would be provided by observations using the same method. We find that the broad line region is the main contributor to the delay between the polarized flux and the total flux; this delay is independent on the observation wavelength. This validates the use of polarized radiation in the optical/UV band to estimate the geometrical properties of the broad line region in type I AGNs, in which the viewing angle is close to pole-on and the BLR is not obscured by the dust torus.
- [32] arXiv:2004.03964 [pdf, ps, other]
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Title: Gamma-ray flux depressions of the Crab nebula in the high-energy rangeComments: 5 pages, 7 figures. After the submission of this paper on the March 30, a study of the same issue appeared in the arXiv (arXiv:2004.03562)Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)
The giant gamma-ray flares of the Crab nebula discovered by AGILE and Fermi observatories came as a surprise and have challenged the existing models of pulsar wind nebulae. We have carried out an analysis of 10.5 years of Fermi-LAT observations (Aug 2008 -- Feb 2019) and investigated variability of the Crab nebula in the 100-300 MeV range. Besides the flares, we found several month long depressions of the gamma-ray flux and identified several cases of sharp flux drops, where during one week the flux decreased by an order of magnitude with respect to its average value. No statistically significant variations of the nebula flux in the E>10 GeV range were found in the data. We discuss possible implications of the observed gamma-ray flux depressions on the model of synchrotron emission of the Crab nebula.
- [33] arXiv:2004.03968 [pdf]
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Title: The Astrobiological Copernican Weak and Strong Limits for Extraterrestrial Intelligent LifeComments: Astrophysical Journal, in press, 47 pagesSubjects: Earth and Planetary Astrophysics (astro-ph.EP); Astrophysics of Galaxies (astro-ph.GA); Solar and Stellar Astrophysics (astro-ph.SR)
We present a cosmic perspective on the search for life and examine the likely number of Communicating Extra-Terrestrial Intelligent civilizations (CETI) in our Galaxy by utilizing the latest astrophysical information. Our calculation involves Galactic star-formation histories, metallicity distributions, and the likelihood of stars hosting Earth-like planets in Habitable Zones, under specific assumptions which we describe as the Astrobiological Copernican Weak and Strong conditions. These assumptions are based on the one situation in which intelligent, communicative life is known to exist - on our own planet. This type of life has developed in a metal-rich environment and has taken roughly 5 Gyr to do so. We investigate the possible number of CETI based on different scenarios. At one extreme is the Weak Astrobiological Copernican principle - such that a planet forms intelligent life sometime after 5 Gyr, but not earlier. The other is the Strong Condition in which life must form between 4.5 to 5.5 Gyr, as on Earth. In the Strong Condition (a strict set of assumptions), there should be at least 36$_{-32}^{+175}$ civilizations within our Galaxy: this is a lower limit, based on the assumption that the average life-time, L, of a communicating civilization is 100 years (based on our own at present). If spread uniformly throughout the Galaxy this would imply that the nearest CETI is at most 17000$_{-10000}^{+33600}$ light-years away, and most likely hosted by a low-mass M-dwarf star, far surpassing our ability to detect it for the foreseeable future. Furthermore, the likelihood that the host stars for this life are solar-type stars is extremely small and most would have to be M-dwarfs, which may not be stable enough to host life over long timescales. We furthermore explore other scenarios and explain the likely number of CETI there are within our Galaxy based on variations of our assumptions.
- [34] arXiv:2004.03986 [pdf, other]
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Title: Spectral signatures of H-rich material stripped from a non-degenerate companion by a Type Ia supernovaAuthors: Luc Dessart (IAP, Paris), Doug Leonard (San Diego State University), Jose-Luis Prieto (Universidad Diego Portales, Chile)Comments: Accepted for publication in A&ASubjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA)
The single-degenerate scenario for Type Ia supernovae (SNe Ia) should yield metal-rich ejecta that enclose some stripped material from the non-degenerate H-rich companion star. We present a large grid of non-local thermodynamic equilibrium steady-state radiative transfer calculations for such hybrid ejecta and provide analytical fits for the Halpha luminosity and equivalent width. Our set of models covers a range of masses for 56Ni and the ejecta, for the stripped material (Mst), and post-explosion epochs from 100 to 300d. The brightness contrast between stripped material and metal-rich ejecta challenges the detection of HI and HeI lines prior to ~100d. Intrinsic and extrinsic optical depth effects also influence the radiation emanating from the stripped material. This inner denser region is marginally thick in the continuum and optically thick in all Balmer lines. The overlying metal-rich ejecta blanket the inner regions, completely below about 5000A, and more sparsely at longer wavelengths. As a consequence, Hbeta should not be observed for all values of Mst through at least 300 days, while Halpha should be observed after ~100d for all Mst >= 0.01Msun. This contrasts with the case of circumstellar (CSM) interaction, not subject to external blanketing, which should produce Halpha and Hbeta lines with a strength dependent primarily on CSM density. We confirm previous analyses that suggest low values of order 0.001Msun for Mst to explain the observations of the two SNe Ia with nebular-phase Halpha detection, in conflict with the much greater stripped mass predicted by hydrodynamical simulations for the single-degenerate scenario. A more likely solution is the double-degenerate scenario, together with CSM interaction, or enclosed material from a tertiary star in a triple system or from a giant planet. [Abridged]
- [35] arXiv:2004.03987 [pdf, other]
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Title: A new fitting function for GRB MeV spectra based on the internal shock synchrotron modelSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
While the Band function or other phenomenological functions are commonly used to fit GRB prompt emission spectra, we propose a new parametric function that is inspired by an internal shock physical model. We use this function as a proxy of the model to confront it easily to GRB observations. We built a parametric function that represents the spectral form of the synthetic bursts provided by our internal shock synchrotron model (ISSM). We simulated the response of the Fermi instruments to the synthetic bursts and fitted the obtained count spectra to validate the ISSM function. Then, we applied this function to a sample of 74 bright GRBs detected by the Fermi/GBM, and we computed the width of their spectral energy distributions around their peak energy. For comparison, we fitted also the phenomenological functions that are commonly used in the literature. Finally, we performed a time-resolved analysis of the broadband spectrum of GRB 090926A, which was jointly detected by the Fermi GBM and LAT. The ISSM function reproduces 81% of the spectra in the GBM bright GRB sample, versus 59% for the Band function, for the same number of parameters. It gives also relatively good fits to the GRB 090926A spectra. The width of the MeV spectral component that is obtained from the fits of the ISSM function is slightly larger than the width from the Band fits, but it is smaller when observed over a wider energy range. Moreover, all of the 74 analysed spectra are found to be significantly wider than the synthetic synchrotron spectra. We discuss possible solutions to reconcile the observations with the internal shock synchrotron model, such as an improved modeling of the shock micro-physics or more accurate spectral measurements at MeV energies.
- [36] arXiv:2004.03993 [pdf, other]
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Title: Fast Ejecta Resulted from Jet-Wind Interaction in the Great Eruption of Eta CarinaeComments: Accepted for publication in MNRASSubjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA)
The accretion model for the nineteenth century Great Eruption (GE) of $\eta$ Carinae suggests that mass outflowing from the primary was accreted onto the secondary, and the gravitational energy of that mass accounts for the increase in luminosity and most of the kinetic energy of the ejecta. It further argues that the accretion was accompanied by the ejection of two jets that shaped the bipolar Homunculus nebula. Observations of echos from the GE found emission lines with broad wings suggesting some of the mass in equatorial directions reached more than $10\,000 \,\rm{km\,s^{-1}}$. We run hydrodynamic simulations following periastron passage during the GE, launching jets from the secondary as it accreted gas erupted from the primary. We then follow the interaction of the polar jets with the surrounding primary wind, as they accelerate part of the flow to velocities $ > 10\,000 \,\rm{km\,s^{-1}}$ and deflect it towards lower latitudes. We find that the amount of mass that reached these high velocities during the GE is $M_h \approx 0.02 \,\rm{M_{\odot}}$. This value reaches maximum and then decreases with time. Our simulations agree with previous results of the accretion model from which we estimate $M_h$ taking into account the energy budget of the GE. The accretion model can explain the observations of high velocity gas in light echos with the known two stars, and a triple star system is not required.
- [37] arXiv:2004.04009 [pdf, other]
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Title: Constraining extra dimensions on cosmological scales with LISA future gravitational wave siren dataComments: 25 pages, 9 figures, 9 tablesSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc)
We investigate the idea that current cosmic acceleration could be the consequence of gravitational leakage into extra dimensions on cosmological scales rather than the result of a non-zero cosmological constant, and consider the ability of future gravitational-wave siren observations to probe this phenomenon and constrain the parameters of phenomenological models of this gravitational leakage. In theories that include additional non-compact spacetime dimensions, the gravitational leakage intro extra dimensions leads to a reduction in the amplitude of observed gravitational waves and thereby a systematic discrepancy between the distance inferred to such sources from GW and EM observations. We investigate the capability of a gravitational space interferometer such as LISA to probe this modified gravity on large scales. We find that the extent to which LISA will be able to place limits on the number of spacetime dimensions and other cosmological parameters characterising modified gravity will strongly depend on the actual number and redshift distribution of sources, together with the uncertainty on the GW measurements. A relatively small number of sources ($\sim 1$) and high measurement uncertainties would strongly restrict the ability of LISA to place meaningful constraints on the parameters in cosmological scenarios where gravity is only five-dimensional and modified at scales larger than about $\sim 4$ times the Hubble radius. Conversely, if the number of sources observed amounts to a four-year average of $\sim 27$, then in the most favourable cosmological scenarios LISA has the potential to place meaningful constraints on the cosmological parameters with a precision of $\sim 1\%$ on the number of dimensions and $\sim 7.5\%$ on the scale beyond which gravity is modified, thereby probing the late expansion of the universe up to a redshift of $\sim 8$.
- [38] arXiv:2004.04012 [pdf]
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Title: A Dimensional Analysis of the Galactic Baryonic Tully-Fisher Relation with Comparison to MOND and Dark Matter Halo DynamicsAuthors: Jeffrey M. La FortuneComments: Comments welcomeSubjects: Astrophysics of Galaxies (astro-ph.GA)
Most rotationally-supported galaxies strictly follow the Baryonic Tully-Fisher Relation (BFTR) linking circular velocity with baryon content. This firmly established empirical relationship is currently thought to have origins in either modified gravity or dark matter halo effects. In this work, we construct a physically-based version of the BFTR founded on known scaling relations, disk dynamics (acceleration, jerk and snap) that also reveals the foundational elements responsible for this phenomenology. We employ the Milky Way galaxy as an exemplar to quantitatively compare the two leading theories against this improved version. Additionally, a dimensionless variant of the BFTR is also provided which may permit its use as an analytic tool to aid in the understanding of galactic dynamics.
- [39] arXiv:2004.04039 [pdf]
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Title: Quadrantids and December alpha Draconids 2012-2019 -- Multi-year Meteor VideographyAuthors: A. R. PrattComments: Accepted for publication in the Journal of the British Astronomical Association. 13 pages, 10 figures, 5 tablesSubjects: Earth and Planetary Astrophysics (astro-ph.EP); Instrumentation and Methods for Astrophysics (astro-ph.IM)
NEMETODE, a network of low-light video cameras in and around the British Isles, operated in conjunction with the BAA Meteor Section and other groups, monitors the activity of meteors, enabling the precision measurement of radiant positions and the altitudes and geocentric velocities of meteoroids and their solar system orbits. The results from observations of the Quadrantid and December alpha Draconid meteor showers during 2012-2019 are presented and discussed.
- [40] arXiv:2004.04063 [pdf, other]
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Title: Stellar coronal mass ejections II. Constraints from spectroscopic observationsComments: 35 pages, 11 figures, 6 tables; MNRAS, acceptedSubjects: Solar and Stellar Astrophysics (astro-ph.SR)
Detections of stellar coronal mass ejections (CMEs) are still rare. Observations of strong Balmer line asymmetries during flare events have been interpreted as being caused by CMEs. Here, we aim to estimate the maximum possible Balmer line fluxes expected from CMEs to infer their detectability in spectroscopic observations. Moreover, we use these results together with a model of intrinsic CME rates to infer the potentially observable CME rates for stars of different spectral types under various observing conditions, as well as the minimum required observing time to detect stellar CMEs in Balmer lines. We find that generally CME detection is favored for mid- to late-type M dwarfs, as they require the lowest signal-to-noise ratio for CME detection, and the fraction of observable-to-intrinsic CMEs is largest. They may require, however, longer observing times than stars of earlier spectral types at the same activity level, as their predicted intrinsic CME rates are lower. CME detections are generally favored for stars close to the saturation regime, because they are expected to have the highest intrinsic rates; the predicted minimum observing time to detect CMEs on just moderately active stars is already >100 h. By comparison with spectroscopic data sets including detections as well as non-detections of CMEs, we find that our modeled maximum observable CME rates are generally consistent with these observations on adopting parameters within the ranges determined by observations of solar and stellar prominences.
- [41] arXiv:2004.04074 [pdf, other]
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Title: Rastall gravity extension of the standard $Λ$CDM model: Theoretical features and observational constraintsComments: 16 pages, 6 figures, 2 tablesSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc)
We present a detailed investigation of the Rastall gravity extension of the standard---six-parameter base---$\Lambda$CDM model. We review the model for two simultaneous modifications of different nature in the Friedmann equation due to the Rastall gravity: the new contributions of the material (actual) sources (considered as effective source) and the altered evolution of the material sources. We discuss the role/behavior of these modifications with regard to some low redshift tensions, including the $H_0$ tension, prevailing within the standard $\Lambda$CDM. We constrain the model at the level of linear perturbations, and give the first constraints through a robust and accurate analysis using the latest full Planck cosmic microwave background (CMB) data, with and without including baryon acoustic oscillations (BAO) data. We find that the Rastall parameter $\epsilon$ (null for general relativity) is consistent with zero at 68% CL (with a tendency towards negative values, $-0.0014 < \epsilon < 0.0002$ (CMB+BAO) at 68% CL), which in turn implies no significant statistical evidence for deviation from general relativity, and also a precision of $\mathcal{O}(10^{-3})$ for the term $-\frac{1}{2}g_{\mu\nu}R$ of the Einstein field equations of general relativity (guaranteeing the local energy-momentum conservation law). We explore the consequences led by the Rastall gravity on the cosmological parameters in the light of the observational analyses. It turns out that the two simultaneous modifications of different nature in the Friedmann equation act against each other, and consequently do not help to relax the so called low redshift tensions. Our results may offer a guide for the research community that studies the Rastall gravity in various aspects of gravitation and cosmology.
- [42] arXiv:2004.04083 [pdf, other]
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Title: A very young radio-loud magnetarAuthors: P. Esposito, N.Rea, A. Borghese, F. Coti Zelati, D.Viganò, G. L. Israel, A.Tiengo, A. Ridolfi, A. Possenti, M. Burgay, D. Götz, F. Pintore, L. Stella, C. Dehman, M. Ronchi, S. Campana, A. Garcia-Garcia, V. Graber, S. Mereghetti, R. Perna, R. Turolla, S. ZaneComments: 9 pages, 4 figures, 1 table; submitted to ApJLSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
The magnetar Swift J1818.0-1607 was discovered in March 2020 when Swift revealed a 9 ms hard X-ray burst and long-lived outburst. Prompt X-ray observations revealed a spin period of $1.36$ s, soon confirmed by the detection of radio pulsations. We report here on the analysis of the Swift} burst and follow-up X-ray and radio observations. The burst average luminosity was $L_{\rm burst} \sim2\times 10^{39}$ erg s$^{-1}$ (at 4.8 kpc). Simultaneous observations with XMM-Newton and NuSTAR three days after the burst provided a source spectrum well fit by an absorbed blackbody ($N_{\rm H} =(1.22\pm0.03) \times 10^{23}$ cm$^{-2}$ and $kT = 1.19\pm0.02$ keV) plus a power-law ($\Gamma=0.1_{-1.4}^{+1.2}$) in the 0.3-20 keV band, with a luminosity of $\sim$$7\times10^{34}$ erg s$^{-1}$, dominated by the blackbody emission. From our timing analysis, we derive a dipolar magnetic field $B \sim 7\times10^{14}$ G, spin-down luminosity $\dot{E}_{\rm rot} \sim 1.4\times10^{36}$ erg s$^{-1}$ and characteristic age of 240 yr, the shortest currently known. Archival observations led to an upper limit on the quiescent luminosity $< 6.5\times10^{33}$ erg s$^{-1}$, lower than the value expected from magnetar cooling models. A 1 hr radio observation with the Sardinia Radio Telescope detected a number of strong and short radio pulses at 1.5 GHz, in addition to regular pulsed emission; they were emitted at an average rate 0.9 min$^{-1}$ and accounted for $\sim$50% of the total pulsed radio fluence. We conclude that Swift J1818.0-1607 is a peculiar magnetar belonging to the small, diverse group of young neutron stars with properties straddling those of rotationally and magnetically powered pulsars.
- [43] arXiv:2004.04115 [pdf, other]
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Title: Long-period eclipsing binaries: towards the true mass-luminosity relation. I. The test sample, observations and data analysisAuthors: Alexei Yu. Kniazev (1 and 2 and 3), Oleg Yu. Malkov (4), Ivan Yu. Katkov (3 and 5 and 6), Leonid N. Berdnikov (3) ((1) South African Astronomical Observatory, (2) Southern African Large Telescope, (3) Sternberg Astronomical Institute, (4) Institute of Astronomy of RAS, (5) New York University Abu Dhabi, (6) Center for Astro, Particle, and Planetary Physics)Comments: 12 pages, 6 figures, accepted by Research in Astronomy and AstrophysicsSubjects: Solar and Stellar Astrophysics (astro-ph.SR)
The mass-luminosity relation is a fundamental law of astrophysics. We have suggested that the currently used mass-luminosity relation is not correct for the M/M_sun > 2.7 range of mass since it was created using double-lined eclipsing binaries, where the components are synchronized and consequently change each other's evolutionary path. To exclude this effect we have started a project to study long-period massive eclipsing binaries in order to construct radial velocity curves and determine masses for the components. We outline our project and present the selected test sample together with the first HRS/SALT spectral observations and the software package, FBS (Fitting Binary Stars), that we developed for the analysis of our spectral data. As the first result we present the radial velocity curves and best-fit orbital elements for the two components of the FP Car binary system from our test sample.
- [44] arXiv:2004.04131 [pdf, ps, other]
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Title: A computational theoretical approach for mining data on transient events from databases of high energy astrophysics experimentsComments: 9 pages, 6 figures (in colors). Conference poster at Third Rome Workshop on Gamma-Ray Bursts in the Afterglow Era, Held 27-30 September 2002 at CNR Headquarters, Rome, ItalyJournal-ref: ASP Conference Series, Vol. 312, pages 528-531, 2004Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Artificial Intelligence (cs.AI)
Data on transient events, like GRBs, are often contained in large databases of unstructured data from space experiments, merged with potentially large amount of background or simply undesired information. We present a computational formal model to apply techniques of modern computer science -such as Data Mining (DM) and Knowledge Discovering in Databases (KDD)- to a generic, large database derived from a high energy astrophysics experiment. This method is aimed to search, identify and extract expected information, and maybe to discover unexpected information .
- [45] arXiv:2004.04132 [pdf, other]
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Title: The $\textit{Gaia}$ Ultra-Cool Dwarf Sample $-$ III: Seven new multiple systems containing at least one $\textit{Gaia}$ DR2 ultra-cool dwarfAuthors: F. Marocco (1,2), R. L. Smart (3), E. E. Mamajek (1), L. M. Sarro (4), A. J. Burgasser (5), J. A. Caballero (6), J. M. Rees (5), D. Caselden (7), K. L. Cruz (8,9,10), R. Van Linge (5), D. J. Pinfield (11) ((1) Jet Propulsion Laboratory, Caltech, USA, (2) IPAC, Caltech, USA, (3) INAF, Osservatorio Astrofisico di Torino, Italy, (4) UNED, Spain, (5) UC San Diego, USA, (6) Centro de Astrobiologia, CSIC-INTA, Spain, (7) Gigamon ATR, USA, (8) Hunter College, USA, (9) City University of New York, USA, (10) American Museum of Natural History, USA, (11) University of Hertfordshire, UK)Comments: Accepted for publication on MNRASSubjects: Solar and Stellar Astrophysics (astro-ph.SR); Earth and Planetary Astrophysics (astro-ph.EP); Astrophysics of Galaxies (astro-ph.GA)
We present ten new ultra-cool dwarfs in seven wide binary systems discovered using $\textit{Gaia}$ DR2 data, identified as part of our $\textit{Gaia}$ Ultra-Cool Dwarf Sample project. The seven systems presented here include an L1 companion to the G5 IV star HD 164507, an L1: companion to the V478 Lyr AB system, an L2 companion to the metal-poor K5 V star CD-28 8692, an M9 V companion to the young variable K0 V star LT UMa, and three low-mass binaries consisting of late Ms and early Ls. The HD 164507, CD-28 8692, V478 Lyr, and LT UMa systems are particularly important benchmarks, because the primaries are well characterised and offer excellent constraints on the atmospheric parameters and ages of the companions. We find that the M8 V star 2MASS J23253550+4608163 is $\sim$2.5 mag overluminous compared to M dwarfs of similar spectral type, but at the same time it does not exhibit obvious peculiarities in its near-infrared spectrum. Its overluminosity cannot be explained by unresolved binarity alone. Finally, we present an L1+L2 system with a projected physical separation of 959 au, making this the widest L+L binary currently known.
Cross-lists for Thu, 9 Apr 20
- [46] arXiv:2004.02921 (cross-list from hep-ph) [pdf, other]
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Title: Dark matter and Standard Model reheating from conformal GUT inflationComments: 38 pages, 9 figuresSubjects: High Energy Physics - Phenomenology (hep-ph); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Theory (hep-th)
Spontaneous breaking of conformal symmetry has been widely exploited in successful model building of both inflationary cosmology and particle physics phenomenology. Conformal Grand Unified Theory (CGUT) inflation provides the same scalar tilt and tensor-to-scalar ratio as of Starobinsky and Higgs inflation. Moreover, it predicts a proton life time compatible with the current experimental bound. In this paper, we extend CGUT to account for the production of dark matter and the reheating of the Standard Model. To this end, we introduce a hidden sector directly coupled to the inflaton, whereas the reheating of the visible sector is realized through a portal coupling between the dark particles and the Higgs boson. The masses and interactions of the dark particles and the Higgs boson are determined by the form of the conformal potential and the non-vanishing VEV of the inflaton. We provide benchmark points in the parameter space of the model that give the observed dark matter relic density and reheating temperatures compatible with the Big Bang nucleosynthesis.
- [47] arXiv:2004.03052 (cross-list from physics.ed-ph) [pdf, other]
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Title: An Interactive Gravitational-Wave Detector Model for Museums and FairsAuthors: S. J. Cooper, A. C. Green, H. R. Middleton, C. P. L. Berry, R. Buscicchio, E. Butler, C. J. Collins, C. Gettings, D. Hoyland, A. W. Jones, J. H. Lindon, I. Romero-Shaw, S. P. Stevenson, E. P. Takeva, S. Vinciguerra, A. Vecchio, C. M. Mow-Lowry, A. FreiseComments: For the associated website, see this http URLSubjects: Physics Education (physics.ed-ph); Instrumentation and Methods for Astrophysics (astro-ph.IM); General Relativity and Quantum Cosmology (gr-qc)
In 2015 the first observation of gravitational waves marked a breakthrough in astrophysics, and in technological research and development. The discovery of a gravitational-wave signal from the collision of two black holes, a billion light-years away, received considerable interest from the media and public. We describe the development of a purpose-built exhibit explaining this new area of research to a general audience. The core element of the exhibit is a working Michelson interferometer: a scaled-down version of the key technology used in gravitational-wave detectors. The Michelson interferometer is integrated into a hands-on exhibit, which allows for user interaction and simulated gravitational-wave observations. An interactive display provides a self-guided explanation of gravitational-wave related topics through video, animation, images and text. We detail the hardware and software used to create the exhibit, and discuss two installation variants: an independent learning experience in a museum setting (the Thinktank Birmingham Science Museum), and a science-festival with the presence of expert guides (the 2017 Royal Society Summer Science Exhibition). We assess audience reception in these two settings, describe the improvements we have made given this information, and discuss future public-engagement projects resulting from this work. The exhibit is found to be effective in communicating the new and unfamiliar field of gravitational-wave research to general audiences. An accompanying website provides parts lists and information for others to build their own version of this exhibit.
- [48] arXiv:2004.03570 (cross-list from hep-th) [pdf, other]
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Title: Evolution of diffuse scalar clouds around binary black holesAuthors: Leong Khim WongComments: 15 pages + appendices, 3 figuresSubjects: High Energy Physics - Theory (hep-th); High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc)
The use of modern effective field theory techniques has sparked significant developments in many areas of physics, including the study of gravity. Case in point, such techniques have recently been used to show that binary black holes can amplify incident, low-frequency radiation due to an interplay between absorption at the horizons and momentum transfer in the bulk spacetime. In this paper, we further examine the consequences of this superradiant-like mechanism on the dynamics of an ambient scalar field by taking the binary's long-range gravitational potential into account at the nonperturbative level. Doing so allows us to capture the formation of scalar clouds that are gravitationally bound to the binary. If the scalar is sufficiently light, the cloud can be diffuse enough (i.e., dilute while having considerable spatial extent) that it engulfs the binary as a whole. Its subsequent evolution exhibits an immensely rich phenomenology, which includes exponential growth, beating patterns, and the upscattering of bound states into scalar waves. While we find that these effects have negligible influence on the binary's inspiral in the regime wherein our approximations are valid, they offer new, analytic insight into how binary black holes interact with external perturbations. They may also provide useful, qualitative intuition for interpreting the results from future numerical simulations of these complex systems.
- [49] arXiv:2004.03626 (cross-list from gr-qc) [pdf, other]
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Title: Tests of general relativity with stellar-mass black hole binaries observed by LISASubjects: General Relativity and Quantum Cosmology (gr-qc); High Energy Astrophysical Phenomena (astro-ph.HE)
We consider the observation of stellar-mass black holes binaries with the Laser Interferometer Space Antenna (LISA). Preliminary results based on Fisher information matrix analyses have suggested that gravitational waves from those sources could be very sensitive to possible deviations from the theory of general relativity and from the strong equivalence principle during the low-frequency binary inspiral. We perform a full Markov Chain Monte Carlo Bayesian analysis to quantify the sensitivity of these signals to two phenomenological modifications of general relativity, namely a putative gravitational dipole emission and a non-zero mass for the graviton, properly accounting for the detector's response. Moreover, we consider a scenario where those sources could be observed also with Earth-based detectors, which should measure the coalescence time with precision better than $1 \ {\rm ms}$. This constraint on the coalescence time further improves the bounds that we can set on those phenomenological deviations from general relativity. We show that tests of dipole radiation and the graviton's mass should improve respectively by seven and half an order(s) of magnitude over current bounds. Finally, we discuss under which conditions one may claim the detection of a modification to general relativity.
- [50] arXiv:2004.03886 (cross-list from physics.hist-ph) [pdf, other]
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Title: John Couch Adams: mathematical astronomer, college friend of George Gabriel Stokes and promotor of women in astronomyAuthors: Davor Krajnović (AIP)Comments: 17 pages, 1 figure; accepted for publication in "Stokes at 200" issue of Philosophical Transactions A, guest edited by Silvana Cardoso, Julyan Cartwright, Herbert Huppert and Christopher NessSubjects: History and Philosophy of Physics (physics.hist-ph); Earth and Planetary Astrophysics (astro-ph.EP)
John Couch Adams predicted the location of Neptune in the sky, calculated the expectation of the change in the mean motion of the Moon due to the Earth's pull, and determined the origin and the orbit of the Leonids meteor shower which had puzzled astronomers for almost a thousand years. With his achievements Adams can be compared with his good friend George Stokes. Not only were they born in the same year, but were also both senior wranglers, received the Smith's Prizes and Copley medals, lived, thought and researched at Pembroke College, and shared an appreciation of Newton. On the other hand, Adams' prediction of Neptune's location had absolutely no influence on its discovery in Berlin. His lunar theory did not offer a physical explanation for the Moon's motion. The origin of the Leonids was explained by others before him. Adams refused a knighthood and an appointment as Astronomer Royal. He was reluctant and slow to publish, but loved to derive the values of logarithms to 263 decimal places. The maths and calculations at which he so excelled mark one of the high points of celestial mechanics, but are rarely taught nowadays in undergraduate courses. The differences and similarities between Adams and Stokes could not be more striking. This volume attests to the lasting legacy of Stokes' scientific work. What is then Adams' legacy? In this contribution I will outline Adams' life, instances when Stokes' and Adams' lives touched the most, his scientific achievements and a usually overlooked legacy: female higher education and support of a woman astronomer.
- [51] arXiv:2004.03912 (cross-list from gr-qc) [pdf, ps, other]
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Title: Anisotropic instability in a higher order gravity theoryComments: 15 pages, 2 figuresSubjects: General Relativity and Quantum Cosmology (gr-qc); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Theory (hep-th)
We study a metric cubic gravity theory considering odd-parity modes of linear inhomogeneous perturbations on a spatially homogeneous Bianchi type I manifold close to the isotropic de Sitter spacetime. We show that in the regime of small anisotropy, the theory possesses new degrees of freedom compared to General Relativity, whose kinetic energy vanishes in the limit of exact isotropy. From the mass dispersion relation we show that such theory always possesses at least one ghost mode as well as a very short-time-scale (compared to the Hubble time) classical tachyonic (or ghost-tachyonic) instability. In order to confirm our analytic analysis, we also solve the equations of motion numerically and we find that this instability is developed well before a single e-fold of the scale factor. This shows that this gravity theory, as it is, cannot be used to construct viable cosmological models.
- [52] arXiv:2004.03956 (cross-list from gr-qc) [pdf, ps, other]
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Title: Non-topological spontaneously scalarized neutron stars in tensor-multi-scalar theories of gravityComments: 7 pages, 6 figuresSubjects: General Relativity and Quantum Cosmology (gr-qc); High Energy Astrophysical Phenomena (astro-ph.HE)
In the present paper, we numerically construct new non-topological, spontaneously scalarized neutron stars in the tensor-multi-scalar theories of gravity whose target space is a three-dimensional maximally symmetric space, namely either $\mathbb{S}^3$, $\mathbb{H}^3$ or $\mathbb{R}^3$, and in the case of a nontrivial map $\varphi : \text{\it spacetime} \to \text{\it target space}$. The theories of gravity admitting scalarization are characterized by the fact that the field equations always admit the general relativistic solution but for certain ranges of the parameters space it loses stability and nonlinear development of a scalar field is observed. Thus, in order to determine the values of the parameters where such scalarization is possible we studied the stability of the general relativistic solution within the framework of the considered tensor-multi-scalar theories. Based on these results we could obtain a family of scalarized branches characterized by the number of the scalar field nodes. These branches bifurcate from the general relativistic solution at the points where new unstable modes appear and they are energetically more favorable over the pure Einstein solutions. Interestingly, in certain parameter ranges, we could obtain non-uniqueness within a single branch of scalarized solutions.
- [53] arXiv:2004.04016 (cross-list from gr-qc) [pdf, other]
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Title: Very-Extreme-mass-ratio gravitational wave bursts in the Galaxy and neighbors for space-borne detectorsComments: 4 pages, 11 figures, 1 tableSubjects: General Relativity and Quantum Cosmology (gr-qc); High Energy Astrophysical Phenomena (astro-ph.HE)
Two recent papers\citep{xmri1, xmri2} revealed that in our Galaxy, there are very extreme-mass-ratio inspirals composed by brown dwarfs and the supermassive black hole in the center. The event rates they estimated are very considerable for space-borne detectors in the future. However, there are also much more plunge events during the formation of the insprialing orbits. In this work, we calculate the gravitational waves from compact objects (brown dwarf, primordial black hole and etc.) plunging into or being scattered by the center supermassive black hole. We find that the signal-to-noise ratio of this burst gravitational waves are quite large for space-borne detectors. The event rates are estimated as $\sim$ 0.01 in one year for the Galaxy. If we are lucky, this kind of very extreme-mass-ratio bursts (XMRBs) will offer a unique chance to reveal the nearest supermassive black hole and nuclei dynamics. Inside 10 Mpc, the event rate can be as large as 4 per year and the signal is strong enough for space-borne detectors, then we have a good chance to probe the nature of neighboring black holes.
- [54] arXiv:2004.04035 (cross-list from physics.optics) [pdf]
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Title: Focal-ratio-degradation (FRD) mitigation in a multimode fiber link using mode-selective photonic lanternsAuthors: Aurélien Benoît, Stephanos Yerolatsitis, Kerrianne Harrington, Tim A. Birks, Robert R. ThomsonComments: 9 pages, 12 figuresSubjects: Optics (physics.optics); Instrumentation and Methods for Astrophysics (astro-ph.IM)
We present a new way to mitigate focal-ratio degradation (FRD) when using optical fibers to transport multimode light. Our approach exploits a custom multicore fiber (MCF) with six dissimilar cores that are single mode at ~1550 nm wavelength and minimally coupled over 7 m. We fabricated adiabatic mode-selective photonic lanterns (PLs) at each end of the MCF to create a fiber link with multimode ports, the PLs coupling each spatial mode of the multimode ports to a specific core of the MCF and vice versa. The PL-MCF-PL link exhibits superior FRD behavior compared to a conventional multimode fiber that also supports 6 modes, because it inhibits the transfer of light from lower-order modes to higher-order modes. These results open up a potentially powerful new approach to mitigate FRD in multimode fiber links, with particular applications in astronomical instruments.
Replacements for Thu, 9 Apr 20
- [55] arXiv:1709.08933 (replaced) [pdf, other]
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Title: Growth of structure in interacting vacuum cosmologiesComments: 19 pages, 5 figures; v2 references added; v3 matter density parameter in model (ii) corrected, figures and discussion revised, version accepted for publication in PRDSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
- [56] arXiv:1804.01064 (replaced) [pdf, ps, other]
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Title: Constraints on the AGN flares as sources of ultra-high energy cosmic rays from the Fermi-LAT observationsComments: 20 pages, 1 figureJournal-ref: JCAP03(2020)060Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)
- [57] arXiv:1810.12158 (replaced) [pdf, other]
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Title: Atomic hydrogen in IllustrisTNG galaxies: the impact of environment parallelled with local 21-cm surveysAuthors: Adam R. H. Stevens, Benedikt Diemer, Claudia del P. Lagos, Dylan Nelson, Annalisa Pillepich, Toby Brown, Barbara Catinella, Lars Hernquist, Rainer Weinberger, Mark Vogelsberger, Federico MarinacciComments: Published in MNRAS. Main body (full paper): 18 (22) pages, 10 (11) figures. New-found bug introduced in v4 mock plots fixed. BaryMP issue fixed per footnote in Dave et al. (2020). All changes are minor and do not affect text or conclusionsJournal-ref: 2019, MNRAS, 483, 5334; Erratum, 2019, MNRAS, 484, 5499Subjects: Astrophysics of Galaxies (astro-ph.GA)
- [58] arXiv:1901.09934 (replaced) [pdf, other]
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Title: Planetary Giant Impacts: Convergence of High-Resolution Simulations using Efficient Spherical Initial Conditions and SWIFTAuthors: J. A. Kegerreis, V. R. Eke, P. G. Gonnet, D. G. Korycansky, R. J. Massey, M. Schaller, L. F. A. TeodoroComments: Fixed typo in Appx B equation and updated urlsSubjects: Earth and Planetary Astrophysics (astro-ph.EP); Computational Physics (physics.comp-ph)
- [59] arXiv:1902.07666 (replaced) [pdf, other]
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Title: The environmental effects of very large bolide impacts on early Mars explored with a hierarchy of numerical modelsAuthors: Martin Turbet, Cédric Gillmann, François Forget, Baptiste Baudin, Ashley Palumbo, James Head, Özgür KaratekinComments: Accepted for publication in Icarus. Abstract significantly abridged to meet ArXiv size limitJournal-ref: Volume 335, 1 January 2020, 113419Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Atmospheric and Oceanic Physics (physics.ao-ph); Geophysics (physics.geo-ph)
- [60] arXiv:1905.05054 (replaced) [pdf, ps, other]
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Title: Soft X-ray heating as a mechanism of optical continuum generation in solar-type star superflaresAuthors: B.A. NizamovComments: 9 pages, 5 figuresSubjects: Solar and Stellar Astrophysics (astro-ph.SR)
- [61] arXiv:1906.09261 (replaced) [pdf, other]
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Title: Demographics of Planetesimals Formed by the Streaming InstabilityComments: accepted and published in ApJ (a typo in Table 6 (last column for VTPL) is fixed in this version (v4))Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
- [62] arXiv:1907.08625 (replaced) [pdf, ps, other]
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Title: On the disc reflection spectroscopy of NS LMXB Serpens~X-1: analysis of a recent NuSTAR observationComments: 11 pages, 10 figures, 3 tables. Accepted for publication in MNRAS. arXiv admin note: text overlap with arXiv:1902.02190Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)
- [63] arXiv:1907.11087 (replaced) [pdf]
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Title: Enhanced Kinetic Impactor for Deflecting Large Potentially Hazardous Asteroids via Maneuvering Space RocksComments: We added more details about the design results and design methods, which will make it more accessible for reader to reproduce our resultsSubjects: Space Physics (physics.space-ph); Earth and Planetary Astrophysics (astro-ph.EP)
- [64] arXiv:1907.12628 (replaced) [pdf, other]
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Title: Constraints on Light Dark Matter Particles Interacting with Electrons from DAMIC at SNOLABAuthors: A. Aguilar-Arevalo, D. Amidei, D. Baxter, G. Cancelo, B.A. Cervantes Vergara, A.E. Chavarria, E. Darragh-Ford, J.R.T. de Mello Neto, J.C. D'Olivo, J. Estrada, R. Gaïor, Y. Guardincerri, T.W. Hossbach, B. Kilminster, I. Lawson, S.J. Lee, A. Letessier-Selvon, A. Matalon, V.B.B. Mello, P. Mitra, Y.S. Mobarak, J. Molina, S. Paul, A. Piers, P. Privitera, K. Ramanathan, J. Da Rocha, M. Settimo, R. Smida, R. Thomas, J. Tiffenberg, D. Torres Machado, R. Vilar, A.L. VirtoComments: 6 pages, 4 figuresJournal-ref: Phys. Rev. Lett. 123, 181802 (2019)Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Experiment (hep-ex); High Energy Physics - Phenomenology (hep-ph); Instrumentation and Detectors (physics.ins-det)
- [65] arXiv:1908.09409 (replaced) [pdf, ps, other]
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Title: Electric and magnetic axion quark nuggets, their stability and their detectionComments: Some further comments addedSubjects: High Energy Physics - Phenomenology (hep-ph); High Energy Astrophysical Phenomena (astro-ph.HE)
- [66] arXiv:1910.00483 (replaced) [pdf, other]
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Title: A Detailed Description of the CamSpec Likelihood Pipeline and a Reanalysis of the Planck High Frequency MapsComments: 136 pages, 57 figures. Typos corrected. Improved layout and minimiserSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Theory (hep-th)
- [67] arXiv:1910.02318 (replaced) [pdf, other]
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Title: Reconstruction with velocitiesComments: 12 pages, 14 figures, in pressSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
- [68] arXiv:1910.04453 (replaced) [pdf, other]
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Title: Gravitational waves from magnetically-induced thermal neutron star mountainsComments: Updated to match version to appear in MNRASSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc)
- [69] arXiv:1910.08659 (replaced) [pdf, other]
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Title: Revised Astrometric Calibration of the Gemini Planet ImagerAuthors: Robert J. De Rosa, Meiji M. Nguyen, Jeffrey Chilcote, Bruce Macintosh, Marshall D. Perrin, Quinn Konopacky, Jason J. Wang, Gaspard Duchêne, Eric L. Nielsen, Julien Rameau, S. Mark Ammons, Vanessa P. Bailey, Travis Barman, Joanna Bulger, Tara Cotten, Rene Doyon, Thomas M. Esposito, Michael P. Fitzgerald, Katherine B. Follette, Benjamin L. Gerard, Stephen J. Goodsell, James R. Graham, Alexandra Z. Greenbaum, Pascale Hibon, Li-Wei Hung, Patrick Ingraham, Paul Kalas, James E. Larkin, Jérôme Maire, Franck Marchis, Mark S. Marley, Christian Marois, Stanimir Metchev, Maxwell A. Millar-Blanchaer, Rebecca Oppenheimer, David Palmer, Jennifer Patience, Lisa Poyneer, Laurent Pueyo, Abhijith Rajan, Fredrik T. Rantakyrö, Jean-Baptiste Ruffio, Dmitry Savransky, Adam C. Schneider, Anand Sivaramakrishnan, et al. (7 additional authors not shown)Comments: 36 pages, 17 figures, accepted for publication in the Journal of Astronomical Telescopes, Instruments, and Systems. Updated version includes revisions made during the referee processSubjects: Instrumentation and Methods for Astrophysics (astro-ph.IM)
- [70] arXiv:1911.04320 (replaced) [pdf, other]
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Title: Identifying Strong Lenses with Unsupervised Machine Learning using Convolutional AutoencoderAuthors: Ting-Yun Cheng, Nan Li, Christopher J. Conselice, Alfonso Aragón-Salamanca, Simon Dye, Robert B. MetcalfComments: 18 pages, 18 figures. Accepted to MNRASSubjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Cosmology and Nongalactic Astrophysics (astro-ph.CO); Astrophysics of Galaxies (astro-ph.GA)
- [71] arXiv:1911.08878 (replaced) [pdf, other]
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Title: Revised mass-radius relationships for water-rich rocky planets more irradiated than the runaway greenhouse limitAuthors: Martin Turbet, Emeline Bolmont, David Ehrenreich, Pierre Gratier, Jérémy Leconte, Franck Selsis, Nathan Hara, Christophe LovisComments: Accepted for publication in A&A. The abstract is abridged to meet ArXiv size limitSubjects: Earth and Planetary Astrophysics (astro-ph.EP); Atmospheric and Oceanic Physics (physics.ao-ph); Geophysics (physics.geo-ph)
- [72] arXiv:1912.05630 (replaced) [pdf]
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Title: Measurements and semi-empirical calculations of CO2+CH4 and CO2+H2 collision-induced absorption across a wide range of wavelengths and temperatures. Application for the prediction of early Mars surface temperatureComments: Accepted for publication in Icarus. CO2+H2 and CO2+CH4 CIAs calculated tables (HITRAN format) - as well as predicted early Mars surface temperatures - are available on demand. They are also available for download on IcarusSubjects: Earth and Planetary Astrophysics (astro-ph.EP); Atmospheric and Oceanic Physics (physics.ao-ph); Atomic and Molecular Clusters (physics.atm-clus); Chemical Physics (physics.chem-ph)
- [73] arXiv:1912.06601 (replaced) [pdf, other]
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Title: Lensing-like tensions in the Planck legacy releaseComments: 10 pages, 10 figures, journal accepted versionSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
- [74] arXiv:1912.07386 (replaced) [pdf, other]
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Title: The Evolving Coma Morphology of Interstellar Comet 2I/Borisov with Deep HST ImagingAuthors: Bryce T. BolinComments: 5 pages, 3 figures and 1 table, submitted to MNRAS Letters. arXiv admin note: substantial text overlap with arXiv:1910.14004Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
- [75] arXiv:2001.04454 (replaced) [pdf, ps, other]
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Title: Constraint on the mass of Fuzzy Dark Matter from the rotation curve of Milky WayComments: 7 pages, 4 figures, 2 tables. Discussions improvedSubjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
- [76] arXiv:2001.10241 (replaced) [pdf, other]
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Title: Collimated outflows from long-lived binary neutron star merger remnantsAuthors: Riccardo CiolfiComments: 6 pages, 4 figures; accepted for publication in MNRAS LettersSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR); General Relativity and Quantum Cosmology (gr-qc)
- [77] arXiv:2002.01897 (replaced) [pdf, other]
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Title: Anomalous decay rate of quasinormal modesComments: Updated to published versionSubjects: General Relativity and Quantum Cosmology (gr-qc); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
- [78] arXiv:2002.07765 (replaced) [pdf, other]
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Title: Cool Outflows in Galaxies and their ImplicationsComments: Review accepted for publication in Astronomy & Astrophysics Reviews, 168 pages, 34 figures; slightly revised version with updated text and figure captions. Now electronically published as this https URLSubjects: Astrophysics of Galaxies (astro-ph.GA)
- [79] arXiv:2003.03364 (replaced) [pdf, ps, other]
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Title: Statistical analysis of the results of 20 years of activity of the International VLBI Service for Geodesy and AstrometryAuthors: Zinovy MalkinComments: Fixed several typos in Table 2Journal-ref: Astronomy Reports, Vol. 64, No. 2, pp. 168-188 (2020)Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM)
- [80] arXiv:2003.05156 (replaced) [pdf, ps, other]
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Title: Properties of gamma-ray decay lines in 3D core-collapse supernova models, with application to SN 1987A and Cas AAuthors: A. Jerkstrand, A. Wongwathanarat, H.-T. Janka, M. Gabler, D. Alp, R. Diehl, K. Maeda, J. Larsson, C. Fransson, A. Menon, A. HegerComments: 29 pages, published in MNRASSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
- [81] arXiv:2003.07284 (replaced) [pdf, ps, other]
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Title: Application of a helicity proxy to edge-on galaxiesComments: 10 pages, 9 figures, 2 tables, submitted to MNRASSubjects: Astrophysics of Galaxies (astro-ph.GA)
- [82] arXiv:2003.10029 (replaced) [pdf, other]
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Title: Excitation and charge transfer in low-energy hydrogen atom collisions with neutral manganese and titaniumComments: 9 pages, 3 figures, 5 tables; accepted for publication in A&ASubjects: Solar and Stellar Astrophysics (astro-ph.SR); Atomic Physics (physics.atom-ph)
- [83] arXiv:2003.13864 (replaced) [pdf, other]
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Title: Retrograde-rotating exoplanets experience obliquity excitations in an eccentricity-enabled resonanceAuthors: Steven M. Kreyche, Jason W. Barnes, Billy L. Quarles, Jack J. Lissauer, John E. Chambers, Matthew M. HedmanComments: Accepted to The Planetary Science Journal. Figures 2 and 4b have associated video files hosted at this https URLSubjects: Earth and Planetary Astrophysics (astro-ph.EP)
- [84] arXiv:2004.00619 (replaced) [pdf, other]
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Title: Graviton non-Gaussianities and Parity Violation in the EFT of InflationComments: 17 pages (12+5). v2: updated referencesSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
- [85] arXiv:2004.00636 (replaced) [pdf, other]
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Title: Baryogenesis and Dark Matter from Freeze-InComments: 27 pages + appendices, 16 figuresSubjects: High Energy Physics - Phenomenology (hep-ph); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
- [86] arXiv:2004.01191 (replaced) [pdf, other]
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Title: The fate of disk galaxies in IllustrisTNG clustersAuthors: Gandhali D. Joshi, Annalisa Pillepich, Dylan Nelson, Federico Marinacci, Volker Springel, Vicente Rodriguez-Gomez, Mark Vogelsberger, Lars HernquistComments: Submitted to MNRAS. Key figures: 4 & 17. Comments are welcome. Updated annotations in Figs. 6, 7, 8 & 10Subjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
- [87] arXiv:2004.02715 (replaced) [pdf, other]
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Title: New high-quality strong lens candidates with deep learning in the Kilo Degree SurveyAuthors: R. Li, N. R. Napolitano, C. Tortora, C. Spiniello, L. V. E. Koopmans, Z. Huang, G. Vernardos, S. Chatterjee, B. Giblin, F. Getman, G. Covone, K. KuijkenComments: Submitted to APJSubjects: Astrophysics of Galaxies (astro-ph.GA)
- [88] arXiv:2004.02910 (replaced) [pdf, other]
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Title: IceCube Search for Neutrinos Coincident with Compact Binary Mergers from LIGO-Virgo's First Gravitational-Wave Transient CatalogAuthors: M. G. Aartsen, M. Ackermann, J. Adams, J. A. Aguilar, M. Ahlers, M. Ahrens, C. Alispach, K. Andeen, T. Anderson, I. Ansseau, G. Anton, C. Argüelles, J. Auffenberg, S. Axani, H. Bagherpour, X. Bai, A. Balagopal V., A. Barbano, I. Bartos, S. W. Barwick, B. Bastian, V. Baum, S. Baur, R. Bay, J. J. Beatty, K.-H. Becker, J. Becker Tjus, S. BenZvi, D. Berley, E. Bernardini, D. Z. Besson, G. Binder, D. Bindig, E. Blaufuss, S. Blot, C. Bohm, S. Böser, O. Botner, J. Böttcher, E. Bourbeau, J. Bourbeau, F. Bradascio, J. Braun, S. Bron, J. Brostean-Kaiser, A. Burgman, J. Buscher, R. S. Busse, T. Carver, C. Chen, E. Cheung, D. Chirkin, S. Choi, B. A. Clark, K. Clark, L. Classen, A. Coleman, G. H. Collin, J. M. Conrad, P. Coppin, K. R. Corley, P. Correa, S. Countryman, D. F. Cowen, R. Cross, et al. (313 additional authors not shown)Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)
- [89] arXiv:2004.03195 (replaced) [pdf, ps, other]
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Title: Study of relativistic accretion flow in Kerr-Taub-NUT spacetimeComments: 15 pages, 14 figuresSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
- [90] arXiv:2004.03203 (replaced) [pdf, other]
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Title: Collimated synchrotron threads linking the radio lobes of ESO137-006Authors: M. Ramatsoku, M. Murgia, V. Vacca, P. Serra, S. Makhathini, F. Govoni, O. Smirnov, L. A. L. Andati, E. de Blok, G. I. G. Józsa, P. Kamphuis, D. Kleiner, F. M. Maccagni, D. Cs. Molnár, A. J. T. Ramaila, K. Thorat, S.V. WhiteComments: 5 pages, 4 figures, accepted for publication in A&A lettersSubjects: Astrophysics of Galaxies (astro-ph.GA)
- [91] arXiv:2004.03514 (replaced) [pdf, other]
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Title: Identification of MHD compressible modes in interstellar plasma with synchrotron emission polarizationSubjects: Astrophysics of Galaxies (astro-ph.GA); Plasma Physics (physics.plasm-ph)
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