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New submissions for Tue, 14 Apr 20

[1]  arXiv:2004.05168 [pdf, other]

Title: Spectral Variability of VHS J1256-1257 b from 1 to 5 $μ$m

Authors: Yifan Zhou, Brendan P. Bowler, Caroline V. Morley, Dániel Apai, Tiffany Kataria, Marta L. Bryan, Björn Benneke

Comments: Submitted to AAS Journals. Comments are welcome. 17 pages, 12 figures

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

Multi-wavelength time-resolved observations of rotationally modulated variability from brown dwarfs and giant exoplanets are the most effective method for constraining their heterogeneous atmospheric structures. In a companion paper (Bowler et al. 2020), we reported the discovery of strong near-infrared variability in HST/WFC3/G141 light curves of the very red L-dwarf companion VHS J1256-1257b. In this paper, we present a follow-up 36-hr Spitzer/IRAC Channel 2 light curve together with an in-depth analysis of the HST and the Spitzer data. The combined dataset provides time-resolved light curves of VHS1256b sampling 1.1 to 4.5 $\mu$m. The Spitzer light curve is best-fit with a single sine wave with a period of $22.04\pm0.05$ hr and a peak-to-peak amplitude of $5.76\pm0.04$%. Combining the period with a previously measured projected rotational velocity ($v\sin i$), we find that VHS1256b is most consistent with equatorial viewing geometry. The HST/G141+Spitzer spectral energy distribution favors a $T_{\rm eff}$ of 1000~K, low surface gravity model with disequilibrium chemistry. The spectral variability of VHS1256b is consistent with predictions from partly cloudy models, suggesting heterogeneous clouds are the dominant source of the observed modulations. We find evidence at the $3.3\sigma$ level for amplitude variations within the 1.67$\mu$m CH$_{4}$ band, which is the first such detection for a variable L-dwarf. We compare the HST/G141 time-resolved spectra of three red L-dwarfs with high-amplitude near-infrared rotational modulations and find that although their time-averaged spectra are similar, their spectroscopic variabilities exhibit notable differences. This diversity reinforces the advantage of time-resolved spectroscopic observations for understanding the atmospheres of brown dwarfs and directly-imaged exoplanets.

[2]  arXiv:2004.05169 [pdf, other]

Title: The LOFAR view of intergalactic magnetic fields with giant radio galaxies

Authors: C. Stuardi, S.P. O'Sullivan, A. Bonafede, M. Brüggen, P. Dabhade, C. Horellou, R. Morganti, E. Carretti, G. Heald, M. Iacobelli, V. Vacca

Comments: 25 pages, 9 figures, 3 tables, accepted by A&A

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

Giant radio galaxies (GRGs) are physically large radio sources that extend well beyond their host galaxy environment. Their polarization properties are affected by the poorly constrained magnetic field that permeates the intergalactic medium on Mpc scales. A low frequency ($<$ 200 MHz) polarization study of this class of radio sources is now possible with LOFAR. Here we investigate the polarization properties and Faraday rotation measure (RM) of a catalog of GRGs detected in the LoTSS. This is the first low-frequency polarization study of a large sample of radio galaxies selected on their physical size. We explore the magneto-ionic properties of their under-dense environment and probe intergalactic magnetic fields using the Faraday rotation properties of their radio lobes. We use RM synthesis in the 120-168 MHz band to search for polarized emission and to derive the RM and fractional polarization of each detected source component. We study the depolarization between 1.4 GHz and 144 MHz using images from the NVSS. From a sample of 240 GRGs, we detected 37 sources in polarization, all with a total flux density above 56 mJy. The fractional polarization of the detected GRGs at 1.4 GHz and 144 MHz is consistent with a small amount of Faraday depolarization (a Faraday dispersion $<$ 0.3 rad m$^{-2}$). Our analysis shows that the lobes are expanding into a low-density ($<10^{-5}$ cm$^{-3}$) local environment permeated by weak magnetic fields ($<$0.1 $\mu$G) with fluctuations on scales of 3 to 25 kpc. The presence of foreground galaxy clusters appears to influence the polarization detection rate up to 2R$_{500}$. In general, this work demonstrates the ability of LOFAR to quantify the rarefied environments in which these GRGs exist and highlights them as an excellent statistical sample to use as high precision probes of magnetic fields in the intergalactic medium and the Milky Way.

[3]  arXiv:2004.05170 [pdf, other]

Title: Strong Near-Infrared Spectral Variability of the Young Cloudy L Dwarf Companion VHS J1256-1257 b

Authors: Brendan P. Bowler, Yifan Zhou, Caroline V. Morley, Tiffany Kataria, Marta L. Bryan, Björn Benneke, Konstantin Batygin

Comments: Accepted to ApJ Letters

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

Rotationally-modulated variability of brown dwarfs and giant planets provides unique information about their surface brightness inhomogeneities, atmospheric circulation, cloud evolution, vertical atmospheric structure, and rotational angular momentum. We report results from Hubble Space Telescope/Wide Field Camera 3 near-infrared time-series spectroscopic observations of three companions with masses in or near the planetary regime: VHS J125601.92-125723.9 b, GSC 6214-210 B, and ROXs 42 B b. VHS J1256-1257 b exhibits strong total intensity and spectral variability with a brightness difference of 19.3% between 1.1-1.7 $\mu$m over 8.5 hours and even higher variability at the 24.7% level at 1.27 $\mu$m. The light curve of VHS J1256-1257 b continues to rise at the end of the observing sequence so these values represent lower limits on the full variability amplitude at this epoch. This observed variability rivals (and may surpass) the most variable brown dwarf currently known, 2MASS J21392676+0220226. The implied rotation period of VHS J1256-1257 b is $\approx$21-24 hr assuming sinusoidal modulations, which is unusually long for substellar objects. No significant variability is evident in the light curves of GSC 6214-210 B ($<$1.2%) and ROXs 42 B b ($<$15.6%). With a spectral type of L7, an especially red spectrum, and a young age, VHS J1256-1257 b reinforces emerging patterns between high variability amplitude, low surface gravity, and evolutionary phase near the L/T transition.

[4]  arXiv:2004.05171 [pdf, other]

Title: The relation between galaxies and the warm-hot circumgalactic medium probed with X-ray and UV line absorption in the EAGLE simulation

Authors: Nastasha A. Wijers, Joop Schaye, Benjamin D. Oppenheimer

Comments: 22 pages, 17 figures + 5 pages references and appendices. Submitted to MNRAS

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

We use the EAGLE cosmological simulation to study the distribution of baryons, and FUV (O VI), EUV (Ne VIII) and X-ray (O VII, O VIII, Ne IX, and Fe XVII) line absorbers, around low-redshift galaxies and haloes of different masses. We work with column densities, but quantify their relation with equivalent widths by analysing virtual spectra. Halo gas dominates the highest column density absorption for X-ray lines, but lower-density gas contributes to strong UV absorption lines from O VI and Ne VIII. Of the O VII (O VIII) absorbers detectable in an Athena X-IFU blind survey, we find that 41 (56) per cent arise from haloes with $\mathrm{M}_{\mathrm{200c}} = 10^{12.0 - 13.5} \, \mathrm{M}_{\odot}$. We predict that the Athena X-IFU will be able to observe O VII (O VIII) covering fractions within 100 pkpc of 77 (46) per cent around $\mathrm{M}_{\star} = 10^{10.5 - 11.0} \, \mathrm{M}_{\odot}$ galaxies (59 (82) per cent for $\mathrm{M}_{\star} >10^{11.0} \, \mathrm{M}_{\odot}$), comparable to the covering fractions observable for O VI and Ne VIII by current UV spectrographs. The circumgalactic medium (CGM) contains more metals than the interstellar medium across halo masses. The ions we study here trace the warm-hot, volume-filling phase of the CGM, but are biased towards gas at temperatures corresponding to the collisional ionization peak for each ion, and towards high-metallicity gas. Gas well within the virial radius is mostly collisionally ionized, but around and beyond this radius, and for O VI, photo-ionization becomes significant. Virial-temperature collisional ionization equilibrium ion fractions are a good predictor of column density trends with halo mass, but haloes contain a larger diversity of ions than this single-temperature model predicts.

[5]  arXiv:2004.05179 [pdf, other]

Title: Radio-emission of axion stars

Authors: D.G. Levkov, A.G. Panin, I.I. Tkachev

Comments: 19 pages, 15 figures

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Astrophysics of Galaxies (astro-ph.GA); High Energy Physics - Phenomenology (hep-ph); Optics (physics.optics)

We study parametric instability of compact axion dark matter structures decaying to radiophotons. Corresponding objects - Bose (axion) stars, their clusters, and clouds of diffuse axions - form abundantly in the postinflationary Peccei-Quinn scenario. We develop general description of parametric resonance incorporating finite-volume effects, backreaction, axion velocities and their (in)coherence. With additional coarse-graining, our formalism reproduces kinetic equation for virialized axions interacting with photons. We derive conditions for the parametric instability in each of the above objects, as well as in collapsing axion stars, evaluate photon resonance modes and their growth exponents. As a by-product, we calculate stimulated emission of Bose stars and diffuse axions, arguing that the former can give larger contribution into the radiobackground. In the case of QCD axions, the Bose stars glow and collapsing stars radioburst if the axion-photon coupling exceeds the original KSVZ value by two orders of magnitude. The latter constraint is alleviated for several nearby axion stars in resonance and absent for axion-like particles. Our results show that the parametric effect may reveal itself in observations, from FRB to excess radiobackground.

[6]  arXiv:2004.05180 [pdf, ps, other]

Title: The Parallax of VHS J1256-1257 from CFHT and Pan-STARRS 1

Authors: Trent J. Dupuy, Michael C. Liu, Eugene A. Magnier, William M. J. Best, Isabelle Baraffe, Gilles Chabrier, Thierry Forveille, Stanimir A. Metchev, Pascal Tremblin

Comments: Research Notes of the American Astronomical Society, in press. Arxiv version has additional information about the astrometry (text & figure)

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

We present new parallax measurements from the CFHT Infrared Parallax Program and the Pan-STARRS 3$\pi$ Steradian Survey for the young ($\approx150-300$ Myr) triple system VHS J125601.92$-$125723.9. This system is composed of a nearly equal-flux binary ("AB") and a wide, possibly planetary-mass companion ("b"). The system's published parallactic distance ($12.7\pm1.0$ pc) implies absolute magnitudes unusually faint compared to known young objects and is in tension with the spectrophotometric distance for the central binary ($17.2\pm2.6$ pc). Our CFHT and Pan-STARRS parallaxes are consistent, and the more precise CFHT result places VHS J1256-1257 at $22.2^{+1.1}_{-1.2}$ pc. Our new distance results in higher values for the companion's mass ($19\pm5$ M$_{\rm Jup}$) and temperature ($1240\pm50$ K), and also brings the absolute magnitudes of all three components into better agreement with known young objects.

[7]  arXiv:2004.05187 [pdf, other]

Title: Polluting the pair-instability mass gap for binary black holes through super-Eddington accretion in isolated binaries

Authors: L.A.C. van Son, S. E. de Mink, F. S. Broekgaarden, M. Renzo, S. Justham, E. Laplace, J. Moran-Fraile, D. D. Hendriks, R. Farmer

Comments: submitted

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

The theory for single stellar evolution predicts a gap in the mass distribution of black holes (BHs) between approximately 45--130\Msun, the so-called ``the pair-instability mass gap". We examine whether BHs can pollute the gap after accreting from a stellar companion. To this end, we simulate the evolution of isolated binaries using a population synthesis code, where we allow for super-Eddington accretion. Under our most extreme assumptions, we find that at most about 2\% of all merging binary BH systems contains a BH with a mass in the pair-instability mass gap, and we find that less than 0.5\% of the merging systems has a total mass larger than 90\Msun. We find no merging binary BH systems with a total mass exceeding 100\Msun. We compare our results to predictions from several dynamical pathways to pair-instability mass gap events and discuss the distinguishable features. We conclude that the classical isolated binary formation scenario will not significantly contribute to the pollution of the pair-instability mass gap. The robustness of the predicted mass gap for the isolated binary channel is promising for the prospective of placing constraints on (i) the relative contribution of different formation channels, (ii) the physics of the progenitors including nuclear reaction rates, and (iii), tentatively, the Hubble parameter.

[8]  arXiv:2004.05201 [pdf, other]

Title: Optical Fe II and Near-Infrared Ca II triplet emission in active galaxies: (I) Photoionization modelling

Authors: Swayamtrupta Panda, Mary Loli Martínez-Aldama, Murilo Marinello, Bożena Czerny, Paola Marziani, Deborah Dultzin

Comments: 24 pages, 15 figures, 2 tables; submitted to ApJ (Comments welcome)

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

Optical Fe II emission is a strong feature of quasar spectra originating in the broad-line regions (BLRs). The difficulty in understanding the complex Fe II pseudo-continuum has led us in search of other reliable, simpler ionic species such as Ca II. In this first part of the series, we confirm the strong correlation between the strengths of two emission features, the optical Fe II and the NIR Ca II, both from observations and photoionization modelling. With the inclusion of an up-to-date compilation of observations with both optical Fe II and NIR Ca II measurements, we span a wider and more extended parameter space and confirm the common origin of these two species with our photoionization models using CLOUDY. Taking into account the effect of dust into our modelling, we retrieve the log U - log n parameter space as a function of the strengths of Fe II and Ca II emission. Incorporating a broad range of metallicity and extended cloud columns we reinstate this correlation and explain the emission from the strong Fe II emitting Narrow-Line Seyfert 1 galaxies (NLS1s).

[9]  arXiv:2004.05238 [pdf, other]

Title: Natural inflation with natural number of e-foldings

Authors: Matthew Civiletti, Brandon Delacruz

Journal-ref: Physical Review D 101, 043534 (2020)

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

We examine natural inflation without the use of the standard slow-roll approximation by considering the number of physical e-folds $\ln (a_eH_e/aH)$. We show that $\tilde{H} = aH \propto \cos(A \phi/2)^{2/A^2} \sin(A \phi/2)$ produces a natural inflationary scenario. This model may be solved exactly, showing that the slow-roll approximation overestimates the tensor-to-scalar ratio by about $13-19 \%$ for $n_s \approx 0.96$ and $50-60$ $e$-folds.

[10]  arXiv:2004.05257 [pdf, other]

Title: The Role of the Critical Ionization Velocity Effect in Interstellar Space and the Derived Abundance of Helium

Authors: Gerrit L. Verschuur, Joan T. Schmelz, Mahboubeh Asgari-Targhi

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

Gaussian analysis of new, high-angular-resolution interstellar 21-cm neutral hydrogen emission profile structure more clearly reveals the presence of the previously reported signature of the critical ionization velocity ({\it CIV}) of Helium (34 km s$^{-1}$). The present analysis includes 1496 component line widths for 178 neutral hydrogen profiles in two areas of sky at galactic latitudes around $-$50$^\circ$, well away from the galactic plane. The new data considered here allow the interstellar abundance of Helium to be calculated, and the derived value of 0.095 $\pm$ 0.020 compares extremely well with the value of 0.085 for the cosmic abundance based on solar data. Although the precise mechanisms that give rise to the {\it CIV} effect in interstellar space are not yet understood, our results may provide additional motivation for further theoretical study of how the mechanism operates.

[11]  arXiv:2004.05270 [pdf, other]

Title: Studying the local magnetic field and anisotropy of magnetic turbulence by synchrotron polarization derivative

Authors: Jian-Fu Zhang (Xiangtan Univ.), Ke Hu (Xiangtan Univ.), Jungyeon Cho (Chungnam National Univ.), Alex Lazarian (UW-Madison)

Comments: 11 pages, 7 figures and 1 Table, Accepted by ApJ

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

Due to the inevitable accumulation of the observed information in the direction of the line of sight, it is difficult to measure the local magnetic field of MHD turbulence. However, the correct understanding of the local magnetic field is a prerequisite for reconstructing the Galactic 3D magnetic field. We study how to reveal the local magnetic field direction and the eddy anisotropy on the basis of the statistics of synchrotron polarization derivative with respect to the squared wavelength $dP/d\lambda^2$. In the low frequency and strong Faraday rotation regime, we implement numerical simulations in the combination of multiple statistic techniques, such as structure function, quadrupole ratio modulus, spectral correlation function, correlation function anisotropy and spatial gradient techniques. We find that (1) statistic analysis of $dP/d\lambda^2$ indeed reveals the anisotropy of underlying MHD turbulence, the degree of which increases with the increase of the radiation frequency; (2) the synergy of both correlation function anisotropy and gradient calculation of $dP/d\lambda^2$ enables the measurement of the local magnetic field direction.

[12]  arXiv:2004.05271 [pdf, other]

Title: Cosmology with the Wide-Field Infrared Survey Telescope -- Multi-Probe Strategies

Authors: Tim Eifler, Hironao Miyatake, Elisabeth Krause, Chen Heinrich, Vivian Miranda, Christopher Hirata, Jiachuan Xu, Shoubaneh Hemmati, Melanie Simet, Peter Capak, Ami Choi, Olivier Dore, Cyrille Doux, Xiao Fang, Rebekah Hounsell, Eric Huff, Hung-Jin Huang, Mike Jarvis, Dan Masters, Eduardo Rozo, Dan Scolnic, David N. Spergel, Michael Troxel, Anja von der Linden, Yun Wang, David H. Weinberg, Lukas Wenzl, Hao-Yi Wu

Comments: comments welcome

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

We simulate the scientific performance of the Wide-Field Infrared Survey Telescope (WFIRST) High Latitude Survey (HLS) on dark energy and modified gravity. The 1.6 year HLS Reference survey is currently envisioned to image 2000 deg$^2$ in multiple bands to a depth of $\sim$26.5 in Y, J, H and to cover the same area with slit-less spectroscopy beyond z=3. The combination of deep, multi-band photometry and deep spectroscopy will allow scientists to measure the growth and geometry of the Universe through a variety of cosmological probes (e.g., weak lensing, galaxy clusters, galaxy clustering, BAO, Type Ia supernova) and, equally, it will allow an exquisite control of observational and astrophysical systematic effects. In this paper we explore multi-probe strategies that can be implemented given WFIRST's instrument capabilities. We model cosmological probes individually and jointly and account for correlated systematics and statistical uncertainties due to the higher order moments of the density field. We explore different levels of observational systematics for the WFIRST survey (photo-z and shear calibration) and ultimately run a joint likelihood analysis in N-dim parameter space. We find that the WFIRST reference survey alone (no external data sets) can achieve a standard dark energy FoM of >300 when including all probes. This assumes no information from external data sets and realistic assumptions for systematics. Our study of the HLS reference survey should be seen as part of a future community driven effort to simulate and optimize the science return of WFIRST.

[13]  arXiv:2004.05296 [pdf, other]

Title: Searching the Entirety of Kepler Data. II. Occurrence Rate Estimates for FGK Stars

Authors: Michelle Kunimoto, Jaymie M. Matthews

Comments: 31 pages, 14 figures, accepted for publication in The Astronomical Journal

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

We present exoplanet occurrence rates estimated with approximate Bayesian computation for planets with radii between 0.5-16 $R_{\bigoplus}$ and orbital periods between 0.78-400 days, orbiting FGK dwarf stars. We base our results on an independent planet catalogue compiled from our search of all ~200,000 stars observed over the Kepler mission, with precise planetary radii supplemented by Gaia DR2-incorporated stellar radii. We take into account detection and vetting efficiency, planet radius uncertainty, and reliability against transit-like noise signals in the data. By analyzing our FGK occurrence rates as well as those computed after separating F, G, and K type stars, we explore dependencies on stellar effective temperature, planet radius, and orbital period. We reveal new characteristics of the photoevaporation-driven "radius gap" between ~1.5-2 $R_{\bigoplus}$, indicating that the bimodal distribution previously revealed for $P$ < 100 days exists only over a much narrower range of orbital periods, above which sub-Neptunes dominate and below which super-Earths dominate. Finally, we provide several estimates of the "eta-Earth" value -- the frequency of potentially habitable, rocky planets orbiting Sun-like stars. For planets with sizes 0.75 - 1.5 $R_{\bigoplus}$ orbiting in a conservatively defined Habitable Zone (0.99 - 1.70 AU) around G type stars, we place an upper limit (84.1th percentile) of <0.18 planets per star.

[14]  arXiv:2004.05347 [pdf, other]

Title: The Diffuse Ultraviolet Background Close to the Galactic Plane

Authors: Jayant Murthy, R. C. Henry, James Overduin

Comments: Submitted to MNRAS

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

We have used Voyager and Galex observations to map the diffuse Galactic light near the Galactic equator. We find that most of the observations are relatively faint with surface brightnesses of less than 5,000 photon units. This is important because many ultraviolet telescopes have not observed at low Galactic latitudes because of the fear of a bright diffuse emission. Our data are consistent with emission from interstellar dust grains with albedo ($a$) of 0.2 -- 0.3 and phase function ($g$) $ < 0.7$ at 1100 \AA; $0.2 < a < 0.5; g < 0.8$ at 1500 \AA; and $0.4 < a < 0.6; g < 0.4$ at 2300 \AA.

[15]  arXiv:2004.05379 [pdf, other]

Title: Tuning the Exo-Space Weather Radio for Stellar Coronal Mass Ejections

Authors: Julián D. Alvarado-Gómez (1 and 2), Jeremy J. Drake (2), Federico Fraschetti (2 and 3), Cecilia Garraffo (2 and 4), Ofer Cohen (5), Christian Vocks (1), Katja Poppenhäger (1), Sofia P. Moschou (2), Rakesh K. Yadav (6), Ward B. Manchester IV (7) ((1) Leibniz Institute for Astrophysics Potsdam, (2) Center for Astrophysics | Harvard & Smithsonian, (3) Dept. of Planetary Sciences-Lunar and Planetary Laboratory - University of Arizona (4) Institute for Applied Computational Science - Harvard University (5) University of Massachusetts at Lowell (6) Department of Earth and Planetary Sciences - Harvard University (7) Department of Climate and Space Sciences and Engineering - University of Michigan)

Comments: 13 Pages, 6 Figures, 2 Tables. Accepted for publication in The Astrophysical Journal

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

Coronal mass ejections (CMEs) on stars other than the Sun have proven very difficult to detect. One promising pathway lies in the detection of type II radio bursts. Their appearance and distinctive properties are associated with the development of an outward propagating CME-driven shock. However, dedicated radio searches have not been able to identify these transient features in other stars. Large Alfv\'en speeds and the magnetic suppression of CMEs in active stars have been proposed to render stellar eruptions "radio-quiet". Employing 3D magnetohydrodynamic simulations, we study here the distribution of the coronal Alfv\'en speed, focusing on two cases representative of a young Sun-like star and a mid-activity M-dwarf (Proxima Centauri). These results are compared with a standard solar simulation and used to characterize the shock-prone regions in the stellar corona and wind. Furthermore, using a flux-rope eruption model, we drive realistic CME events within our M-dwarf simulation. We consider eruptions with different energies to probe the regimes of weak and partial CME magnetic confinement. While these CMEs are able to generate shocks in the corona, those are pushed much farther out compared to their solar counterparts. This drastically reduces the resulting type II radio burst frequencies down to the ionospheric cutoff, which impedes their detection with ground-based instrumentation.

[16]  arXiv:2004.05447 [pdf, other]

Title: Simulating White-Light Images of Coronal Structures for Parker Solar Probe/WISPR: Study of the Total Brightness Profiles

Authors: Giuseppe Nisticò, Volker Bothmer, Angelos Vourlidas, Paulett Liewer, Arnaud Thernisien, Guillermo Stenborg, Russell Howard

Comments: 26 pages, 11 figures. Accepted for publication in Solar Physics

Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Space Physics (physics.space-ph)

The Wide-field Imager for Parker Solar Probe (WISPR) captures unprecedented white-light images of the solar corona and inner heliosphere. Thanks to the uniqueness of Parker Solar Probe's (PSP) orbit, WISPR is able to image ``locally'' coronal structures at high spatial and time resolutions. The observed plane of sky, however, rapidly changes because of the PSP's high orbital speed. Therefore, the interpretation of the dynamics of the coronal structures recorded by WISPR is not straightforward. A first study, undertaken by \citet{Liewer2019}, shows how different coronal features (e.g., streamers, flux ropes) appear in the field of view of WISPR by means of raytracing simulations. In particular, they analyze the effects of the spatial resolution changes on both the images and the associated height-time maps, and introduce the fundamentals for geometric triangulation. In this follow-up paper, we focus on the study of the total brightness of a simple, spherical, plasma density structure, to understand how the analysis of Thomson-scattered emission by the electrons in a coronal feature can shed light into the determination of its kinematic properties. We investigate two cases: {\it (a)} a density sphere at a constant distance from the Sun for different heliographic longitudes; {\it (b)} a density sphere moving outwardly with constant speed. The study allows us to characterize the effects of the varying heliocentric distance of the observer and scattering angle on the total brightness observed, which we exploit to contribute to a better determination of the position and speed of the coronal features observed by WISPR.

[17]  arXiv:2004.05453 [pdf, other]

Title: Explaining the absence of symbiotic stars in globular clusters and observational prospects for their identification

Authors: Diogo Belloni, Joanna Mikołajewska, Krystian Iłkiewicz, Matthias R. Schreiber, Mirek Giersz, Liliana E. Rivera Sandoval, Claudia V. Rodrigues

Comments: submitted to MNRAS, 15 pages, comments are welcome

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

Even though plenty of symbiotic stars (SySts) have been found in the Galactic field and nearby galaxies, not a single one has ever been confirmed in a Galactic globular cluster (GC). We investigate the lack of such systems in GCs for the first time by analysing 144 GC models evolved with the MOCCA code, which have different initial properties and are roughly representative of the Galactic GC population. We focus here on SySts formed through the wind-accretion channel, which can be consistently modelled in binary population synthesis codes. We found that the orbital periods of the majority of such SySts are sufficiently long (${\gtrsim10^3}$ days) so that, for very dense GC models, dynamical interactions play an important role in destroying their progenitors before the present day ($\sim11-12$ Gyr). In less dense GC models, some SySts are still predicted to exist. However, these systems tend to have relatively low white dwarf luminosities (${\lesssim100}$ L$_\odot$), are located far from the central parts (${\gtrsim70}$ per cent are far beyond the half-light radius) and are sufficiently rare (${\lesssim1}$ per GC per Myr), which makes their identification rather difficult in current observational campaigns. We propose that future searches for SySts in GCs should be performed with either high-quality spectroscopy or photometry (using narrow-band filters centred on either He II and H$\alpha$ or Raman scattered O VI emission lines), in the outskirts of nearby low-density GCs with sufficiently long half-mass relaxation times and relatively large Galactocentric distances. Finally, we obtained spectra of the candidate proposed in $\omega$ Cen (SOPS IV e-94) and showed that this object is not a SySt.

[18]  arXiv:2004.05475 [pdf, other]

Title: Chaos and Lévy Flights in the Three-Body Problem

Authors: Viraj Manwadkar, Alessandro A. Trani, Nathan W. C. Leigh

Comments: 20 pages, 14 figures

Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Chaotic Dynamics (nlin.CD)

We study chaos and L\'evy flights in the general gravitational three-body problem. We introduce new metrics to characterize the time evolution and final lifetime distributions, namely Scramble Density $\mathcal{S}$ and the LF index $\mathcal{L}$, that are derived from the Agekyan-Anosova maps and homology radius $R_{\mathcal{H}}$. Based on these metrics, we develop detailed procedures to isolate the ergodic interactions and L\'evy flight interactions. This enables us to study the three-body lifetime distribution in more detail by decomposing it into the individual distributions from the different kinds of interactions. We observe that ergodic interactions follow an exponential decay distribution similar to that of radioactive decay. Meanwhile, L\'evy flight interactions follow a power-law distribution. L\'evy flights in fact dominate the tail of the general three-body lifetime distribution, providing conclusive evidence for the speculated connection between power-law tails and L\'evy flight interactions. We propose a new physically-motivated model for the lifetime distribution of three-body systems and discuss how it can be used to extract information about the underlying ergodic and L\'evy flight interactions. We discuss mass ejection probabilities in three-body systems in the ergodic limit and compare it to previous ergodic formalisms. We introduce a novel mechanism for a three-body relaxation process and discuss its relevance in general three-body systems.

[19]  arXiv:2004.05480 [pdf, other]

Title: Chirality of the gravitational-wave background and pulsar-timing arrays

Authors: Enis Belgacem, Marc Kamionkowski

Comments: 7 pages, 2 figures

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

We describe the signatures of a circularly polarized gravitational-wave background on the timing residuals obtained with pulsar-timing arrays. Most generally, the circular polarization will depend on the gravitational-wave direction, and we describe this angular dependence in terms of spherical harmonics. While the amplitude of the monopole (the overall chirality of the gravitational-wave background) cannot be detected, measures of the anisotropy are theoretically conceivable. We provide expressions for the minimum-variance estimators for the circular-polarization anisotropy. We evaluate the smallest detectable signal as a function of the signal-to-noise ratio with which the isotropic GW signal is detected and the number of pulsars (assumed to be roughly uniformly spread throughout the sky) in the survey. We find that the overall dipole of the circular polarization and a few higher overall multipoles, are detectable in a survey with $\gtrsim100$ pulsars if their amplitude is close to maximal and once the isotropic signal is established with a signal-to-noise ratio $\gtrsim400$. Even if the anisotropy can be established, though, there will be limited information on its direction. Similar arguments apply to astrometric searches for gravitational waves.

[20]  arXiv:2004.05514 [pdf, ps, other]

Title: GRB 111209A/SN 2011kl: Collapse of a supramassive magnetar with r-mode oscillation and fall-back accretion onto a newborn black hole

Authors: Jie Lin, Rui-Jing Lu, Da-Bin Lin, Xiang-Gao Wang

Comments: 15 pages, 3 figures. To be accepted for publication in ApJ

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

Ultra-long-duration gamma-ray burst GRB 111209A was found to be associated with a very luminous supernovae (SNe) SN 2011kl. The physics of GRB 111209A/SN 2011kl has been extensively studied in the literures, but does not settle down yet. By investigating in detail the characteristics of the X-ray light curve of GRB 111209A, coupled with the temporal and spectral features observed in SN 2011kl, we argue that a short-living supramassive magnetar can be responsible for the initial shallow X-ray emission. Then the electromagnetic extraction of spin energy from a black hole results in the steeply declining X-ray flux when the magnetar collapses into a black hole (BH). A fraction of the envelope materials falls back and activates the accretion onto the newborn BH, which produces the X-ray rebrightening bump at late times. During this process, a centrifugally driven baryon-rich quasi-isotropic Blandford \& Payne outflow from the revived accretion disk deposits its kinetic energy on the SN ejecta, which powers luminous SN 2011kl. Finally, we place a limitation on the magnetar's physical parameters based on the observations.

[21]  arXiv:2004.05562 [pdf, other]

Title: Direct evidence for shock-powered optical emission in a nova

Authors: Elias Aydi, Kirill V. Sokolovsky, Laura Chomiuk, Elad Steinberg, Kwan Lok Li, Indrek Vurm, Brian D. Metzger, Jay Strader, Koji Mukai, Ondřej Pejcha, Ken J. Shen, Gregg A. Wade, Rainer Kuschnig, Anthony F. J. Moffat, Herbert Pablo, Andrzej Pigulski, Adam Popowicz, Werner Weiss, Konstanze Zwintz, Luca Izzo, Karen R. Pollard, Gerald Handler, Stuart D. Ryder, Miroslav D. Filipović, Rami Z. E. Alsaberi, Perica Manojlović, Raimundo Lopes de Oliveira, Frederick M. Walter, Patrick J. Vallely, David A. H. Buckley, Michael J. I. Brown, Eamonn J. Harvey, Adam Kawash, Alexei Kniazev, Christopher S. Kochanek, Justin Linford, Joanna Mikolajewska, Paolo Molaro, Marina Orio, Kim L. Page, Benjamin J. Shappee, Jennifer L. Sokoloski

Comments: 49 pages including supplementary information. Accepted and published in Nature Astronomy

Journal-ref: Nature Astronomy 2020

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

Classical novae are thermonuclear explosions that occur on the surfaces of white dwarf stars in interacting binary systems (Bode & Evans 2008). It has long been thought that the luminosity of classical novae is powered by continued nuclear burning on the surface of the white dwarf after the initial runaway (Gallaher & Starrfield 1978). However, recent observations of GeV $\gamma$-rays from classical novae have hinted that shocks internal to the nova ejecta may dominate the nova emission. Shocks have also been suggested to power the luminosity of events as diverse as stellar mergers (Metzger & Pejcha 2017), supernovae (Moriya et al. 2018), and tidal disruption events (Roth et al. 2016), but observational confirmation has been lacking. Here we report simultaneous space-based optical and $\gamma$-ray observations of the 2018 nova V906 Carinae (ASASSN-18fv), revealing a remarkable series of distinct correlated flares in both bands. The optical and $\gamma$-ray flares occur simultaneously, implying a common origin in shocks. During the flares, the nova luminosity doubles, implying that the bulk of the luminosity is shock-powered. Furthermore, we detect concurrent but weak X-ray emission from deeply embedded shocks, confirming that the shock power does not appear in the X-ray band and supporting its emergence at longer wavelengths. Our data, spanning the spectrum from radio to $\gamma$-ray, provide direct evidence that shocks can power substantial luminosity in classical novae and other optical transients.

[22]  arXiv:2004.05584 [pdf, ps, other]

Title: Magneto-acoustic waves in a magnetic slab embedded in an asymmetric magnetic environment II: Thin and wide slabs, hot and cold plasmas

Authors: Noémi Kinga Zsámberger, Róbert Erdélyi

Comments: accepted for publication in The Astrophysical Journal; 24 pages, 5 figures

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

Wave propagation in magnetically structured atmospheres is a thoroughly studied, yet practically inexhaustible well of investigations in the field of solar magneto-seismology. A simple but powerful example is the examination of wave behaviour in a magnetic slab. Our previous study (Zs\'amberger, Allcock and Erd\'elyi, Astrophys. J., 853, p. 136, 2018) used an analytical approach to derive the general dispersion relation for magneto-acoustic waves in a magnetic slab of homogeneous plasma, which was enclosed in an asymmetric magnetic environment. In the present study, we focus on the analysis of wave propagation in various limiting cases applicable to solar and space plasma or astrophysics. The thin- and wide-slab approximations, as well as the limits of low and high plasma-beta values are considered. Utilising the fact that in a weakly asymmetric slab, the dispersion relation can be decoupled, the behaviour of quasi-sausage and quasi-kink modes is studied in further analytical and numerical detail, and their avoided crossings are described. The results highlight how the asymmetry influences the wave properties, e.g. the phase speed of eigenmodes, depending on the ratios of external-to-internal densities and magnetic fields on the two sides. Notably, the phase speeds of surface modes will converge to different values for quasi-sausage and quasi-kink modes in the wide-slab limit, and cut-off frequencies are introduced with respect to both surface and body modes, in thin as well as wide slabs, beyond which the solutions become leaky. These obtained properties of MHD wave behaviour could be measured with suitable high-resolution instruments in the future.

[23]  arXiv:2004.05600 [pdf, other]

Title: Radiative Transfer modeling of EC 53: An Episodically Accreting Class I Young Stellar Object

Authors: Giseon Baek, Benjamin A. MacFarlane, Jeong-Eun Lee, Dimitris Stamatellos, Gregory Herczeg, Doug Johnstone, Carlos Contreras Pena, Watson Varricatt, Klaus W. Hodapp, Huei-Ru Vivien Chen, Sung-Ju Kang

Comments: 16 pages, 14 figures, Accepted for publication in ApJ

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

In the episodic accretion scenario, a large fraction of the protostellar mass accretes during repeated and large bursts of accretion. Since outbursts on protostars are typically identified at specific wavelengths, interpreting these outbursts requires converting this change in flux to a change in total luminosity. The Class I young stellar object EC 53 in the Serpens Main cloud has undergone repeated increases in brightness at 850 $\mu$m that are likely caused by bursts of accretion. In this study, we perform two- and three-dimensional continuum radiative transfer modeling to quantify the internal luminosity rise in EC 53 that corresponds to the factor of $\sim$1.5 enhancement in flux at 850 $\mu$m. We model the spectral energy distribution and radial intensity profile in both the quiescent and outburst phases. The internal luminosity in the outburst phase is $\sim 3.3$ times brighter than the luminosity in the quiescent phase. The radial intensity profile analysis demonstrates that the detected sub-mm flux variation of EC 53 comes from the heated envelope by the accretion burst. We also find that the role of external heating of the EC 53 envelope by the interstellar radiation field is insignificant.

[24]  arXiv:2004.05603 [pdf, other]

Title: Estimating, monitoring and minimizing the travel footprint associated with the development of the Athena X-ray Integral Field Unit -- An on-line travel footprint calculator released to the science community

Authors: Didier Barret (IRAP, Toulouse, France)

Comments: 31 pages, 14 figures, Accepted for publication in Experimental Astronomy. The URL of the travel footprint calculator is : this https URL

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

Global warming imposes us to reflect on the way we carry research, embarking on the obligation to minimize the environmental impact of our research programs, with the reduction of our travel footprint being one of the easiest actions to implement, thanks to the advance of digital technology. The X-ray Integral Field Unit (X-IFU), the cryogenic spectrometer of the Athena space X-ray observatory of the European Space Agency will be developed by a large international consortium. The travel footprint associated with the development of the X-IFU is to be minimized. For that purpose, a travel footprint calculator has been developed and first released to the X-IFU consortium members. The calculator uses seven different emission factors and methods differing by up to a factor of ~5 for the same flying distance. The observed differences illustrate the lack of standards and regulations for computing the footprint of flight travels and are explained primarily, though partly, by different accountings of non-CO2 effects. The calculator enables us to compute the travel footprint of a large set of travels and can help identify a meeting place that minimizes the overall travel footprint for a large set of possible city hosts, e.g. cities with large airports. The calculator also includes the option for a minimum distance above which flying is considered the most suitable transport option ; below that chosen distance, the emission of train journeys are considered. To demonstrate its full capabilities, the calculator is first run on one of the largest scientific meetings; the fall meeting of the AGU and meetings of the IPCC for which it is used to compute the location that would minimize the travel footprint. Then the travel footprint of X-IFU is estimated to be ~500 tons of CO2-eq/yr. With this paper, the on-line travel footprint calculator is released to the science community (abridged).

[25]  arXiv:2004.05604 [pdf, other]

Title: The role of Galactic HII regions in the formation of filaments. High-resolution submilimeter imaging of RCW 120 with ArTéMiS

Authors: A. Zavagno, Ph. André, F. Schuller, N. Peretto, Y. Shimajiri, D. Arzoumanian, T. Csengeri, M. Figueira, G.A. Fuller, V. Könyves, A. Men'shchikov, P. Palmeirim, H. Roussel, D. Russeil, N. Schneider, S. Zhang

Comments: 8 pages, 8 figures, accepted by A&A

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

Massive stars and their associated ionized (HII) regions could play a key role in the formation and evolution of filaments that host star formation. However, the properties of filaments that interact with H regions are still poorly known. To investigate the impact of HII regions on the formation of filaments, we imaged the Galactic HII region RCW 120 and its surroundings where active star formation takes place and where the role of ionization feedback on the star formation process has already been studied. We used the ArT\'eMiS camera on the APEX telescope and combined the ArT\'eMiS data at 350 and 450 microns with Herschel-SPIRE/HOBYS. We studied the dense gas distribution around RCW 120 with a resolution of 8 arcsec (0.05 pc at a distance of 1.34 kpc). Our study allows us to trace the median radial intensity profile of the dense shell of RCW 120. This profile is asymmetric, indicating a clear compression from the HII region on the inner part of the shell. The profile is observed to be similarly asymmetric on both lateral sides of the shell, indicating a homogeneous compression over the surface. On the contrary, the profile analysis of a radial filament associated with the shell, but located outside of it, reveals a symmetric profile, suggesting that the compression from the ionized region is limited to the dense shell. The mean intensity profile of the internal part of the shell is well fitted by a Plummer like profile with a deconvolved Gaussian FWHM of 0.09 pc, as observed for filaments in low-mass star-forming regions. This study suggests that compression exerted by HII regions may play a key role in the formation of filaments and may further act on their hosted star formation. ArT\'eMiS data also suggest that RCW 120 might be a 3D ring, rather than a spherical structure

[26]  arXiv:2004.05605 [pdf, other]

Title: Bridging the Ultraviolet and Optical Regions: Transformation Equations between {\it GALEX} and {\it UBV} Photometric Systems

Authors: S. Bilir, N. Alan, S. Tuncel Guctekin, M. Celebi, T. Yontan, O. Plevne, S. Ak, T. Ak, S. Karaali

Comments: 16 pages, including 14 figures and 6 tables, accepted for publication in PASA

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

We derive transformation equations between GALEX and UBV colours by using the reliable data of 556 stars. We present two sets of equations; as a function of (only) luminosity class, and as a function of both luminosity class and metallicity. The metallicities are provided from the literature, while the luminosity classes are determined by using the PARSEC mass tracks in this study. Small colour residuals and high squared correlation coefficients promise accurate derived colours. The application of the transformation equations to 70 stars with reliable data shows that the metallicity plays an important role in estimation of more accurate colours.

[27]  arXiv:2004.05615 [pdf, ps, other]

Title: Signatures of Untwisting Magnetic Field in a Small Emerging Bipole in the Solar Photosphere

Authors: C. R. Sangeetha, Durgesh Tripathi, S. P. Rajaguru

Comments: 27 pages, 10 figures, accepted for publication in The Astrophysical Journal

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

We perform a study of fluid motions and its temporal evolution in and around a small bipolar emerging flux region using observations made by the Helioseismic and Magnetic Imager (HMI) on-board the Solar Dynamics Observatory (SDO). We employ local correlation tracking of the Doppler observations to follow horizontal fluid motions and line-of-sight magnetograms to follow the flux emergence. Changes in vertical vorticity and horizontal divergence are used to derive signatures of evolving twists in the magnetic field. Our analysis reveals that the two polarities of the magnetic flux swirl in opposite directions in early stages of flux emergence indicating an unwinding of the pre-emergence twists in the magnetic field. We further find that during the emergence, there is an increase in swirly motions in the neighbouring non-magnetic regions. We estimate the magnetic and kinetic energies and find that magnetic energy is about a factor of ten larger than the kinetic energy. During the evolution, when the magnetic energy decreases, an increase in the kinetic energy is observed indicating transfer of energy from the unwinding of magnetic flux tube to the surrounding fluid motions. Our results thus demonstrate the presence of pre-emergence twists in emerging magnetic field that is important in the context of the hemispheric helicity rule warranting a detailed statistical study in this context. Further, our observations point to a possible widespread generation of torsional waves in emerging flux regions due to the untwisting magnetic field with implications for upward energy transport to the corona.

[28]  arXiv:2004.05618 [pdf, other]

Title: Noise from Undetected Sources in Dark Energy Survey Images

Authors: K. Eckert (1), G. M. Bernstein (1), A. Amara (2), A. Amon (3), A. Choi (4), S. Everett (5), D. Gruen (6,3,7), R. A. Gruendl (8,9), E. M. Huff (10), N. Kuropatkin (11), A. Roodman (3,7), E. Sheldon (12), B. Yanny (11), Y. Zhang (11), T. M. C. Abbott (13), M. Aguena (14,15), S. Avila (16), K. Bechtol (17,18), D. Brooks (19), D. L. Burke (3,7), A. Carnero Rosell, M. Carrasco Kind (8,9), J. Carretero (21), M. Costanzi (22,23), L. N. da Costa (15,24), J. De Vicente (25), S. Desai (26), H. T. Diehl (11), J. P. Dietrich (27), T. F. Eifler (28,10), A. E. Evrard (29,30), B. Flaugher (11), J. Frieman (11,31), J. García-Bellido (16), E. Gaztanaga (32,33), J. Gschwend (15,24), G. Gutierrez (11), W. G. Hartley (48,19,2), D. L. Hollowood (5), K. Honscheid (4,34), D. J. James (35), R. Kron (11,31), et al. (27 additional authors not shown)

Comments: 13 pages, 10 figures

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

For ground-based optical imaging with current CCD technology, the Poisson fluctuations in source and sky background photon arrivals dominate the noise budget and are readily estimated. Another component of noise, however, is the signal from the undetected population of stars and galaxies. Using injection of artificial galaxies into images, we demonstrate that the measured variance of galaxy moments (used for weak gravitational lensing measurements) in Dark Energy Survey (DES) images is significantly in excess of the Poisson predictions, by up to 30\%, and that the background sky levels are overestimated by current software. By cross-correlating distinct images of "empty" sky regions, we establish that there is a significant image noise contribution from undetected static sources (US), which on average are mildly resolved at DES resolution. Treating these US as a stationary noise source, we compute a correction to the moment covariance matrix expected from Poisson noise. The corrected covariance matrix matches the moment variances measured on the injected DES images to within 5\%. Thus we have an empirical method to statistically account for US in weak lensing measurements, rather than requiring extremely deep sky simulations. We also find that local sky determinations can remove the bias in flux measurements, at a small penalty in additional, but quantifiable, noise.

[29]  arXiv:2004.05620 [pdf, ps, other]

Title: The Isaac Newton Telescope monitoring survey of Local Group dwarf galaxies. I. Survey overview and first results for Andromeda I

Authors: Elham Saremi, Atefeh Javadi, Jacco Th.van Loon, Habib Khosroshahi, Alireza Molaeinezhad, Iain McDonald, Mojtaba Raouf, Arash Danesh, James R. Bamber, Philip Short, Lucia Suárez-Andrés, Rosa Clavero, Ghassem Gozaliasl

Comments: accepted for publication in ApJ

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

An optical monitoring survey in the nearby dwarf galaxies was carried out with the 2.5-m Isaac Newton Telescope (INT). 55 dwarf galaxies and four isolated globular clusters in the Local Group (LG) were observed with the Wide Field Camera (WFC). The main aims of this survey are to identify the most evolved asymptotic giant branch (AGB) stars and red supergiants at the end-point of their evolution based on their pulsational instability, use their distribution over luminosity to reconstruct the star formation history, quantify the dust production and mass loss from modelling the multi-wavelength spectral energy distributions, and relate this to luminosity and radius variations. In this first of a series of papers, we present the methodology of the variability survey and describe the photometric catalogue of Andromeda I (And I) dwarf galaxy as an example of the survey, and discuss the identified long period variable (LPV) stars. We detected 5581 stars and identified 59 LPV candidates within two half-light radii of the centre of And I. The amplitudes of these candidates range from 0.2 to 3 mag in the $i$-band. 75 % of detected sources and 98 % of LPV candidates are detected at mid-infrared wavelengths. We show evidence for the presence of dust-producing AGB stars in this galaxy including five extreme AGB (x-AGB) stars, and model some of their spectral energy distributions. A distance modulus of 24.41 mag for And I was determined based on the tip of the red giant branch (RGB). Also, a half-light radius of 3.2 arcmin is calculated.

[30]  arXiv:2004.05701 [pdf, other]

Title: Using the Modified Lognormal Power Law Distribution to Model the Mass Function of NGC 1711

Authors: Deepakshi Madaan, Sophia Lianou, Shantanu Basu

Comments: 12 pages, 6 figures, to appear in ApJ

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

A determination of the mass function (MF) of stellar clusters can be quite dependent on the range of measured masses, the fitting technique, and the analytic function that is being fit to the data. Here, we use HST/WFPC2 data of NGC 1711, a stellar cluster in the Large Magellanic Cloud, as a test case to explore a range of possible determinations of the MF from a single dataset. We employ the analytic modified lognormal power-law (MLP) distribution, a hybrid function that has a peaked lognormal-like body and a power-law tail at intermediate and high masses. A fit with the MLP has the advantage that the resulting best-fit function can be either a hybrid function, a pure lognormal, or a pure power law, in different limits of the function. The completeness limit for the observations means that the data contains masses above $\sim 0.90\,M_{\odot}$. In this case, the MLP fits yield essentially a pure power-law MF. We demonstrate that the nonlinear regression/least-squares approach is not justified since the underlying assumptions are not satisfied. By using maximum likelihood estimation, which is independent of binning, we find a best-fit functional form $dN/d\ln m \propto m^{-\alpha}$, where $\alpha = 1.72 \pm 0.05$ or $1.75 \pm 0.05$ for two different theoretical isochrone models, respectively. Furthermore, we explore the possibility of systematic errors in the determination of the power-law index due to the depth of the observations. When we combine the observational data with artificially generated data from the lognormal Chabrier IMF for masses below $0.90\, M_{\odot}$, the best fit MLP is a hybrid function but with a steeper asymptotic slope i.e., $\alpha = 2.04 \pm 0.07$. This illustrates the systematic uncertainties in commonly used MF parameters that can depend on the range of data that is fitted.

[31]  arXiv:2004.05724 [pdf, ps, other]

Title: Discovery of Radio Jets in Phoenix Galaxy Cluster Center

Authors: Takuya Akahori, Tetsu Kitayama, Shutaro Ueda, Takuma Izumi, Kianhong Lee, Ryohei Kawabe, Kotaro Kohno, Masamune Oguri, Motokazu Takizawa

Comments: 10 pages, 5 figures, submitted in March 29 2019, accepted for publication in PASJ in April 12 2020

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

We report the results of the Australia Telescope Compact Array (ATCA) 15 mm observation of the Phoenix galaxy cluster possessing an extreme star-burst brightest cluster galaxy (BCG) at the cluster center. We spatially resolved radio emission around the BCG, and found diffuse bipolar and bar-shape structures extending from the active galactic nucleus (AGN) of the BCG. They are likely radio jets/lobes, whose sizes are ~10-20 kpc and locations are aligned with X-ray cavities. If we assume that the radio jets/lobes expand with the sound velocity, their ages are estimated to be ~10 Myr. We also found compact radio emissions near the center and suggest that they are another young bipolar jets with ~1 Myr of age. Moreover, we found extended radio emission surrounding the AGN and discussed the possibility that the component is a product of the cooling flow, by considering synchrotron radiation partially absorbed by molecular clumps, free-free emission from the warm ionized gas, and the spinning dust emission from dusty circum-galactic medium.

[32]  arXiv:2004.05765 [pdf, ps, other]

Title: Particle acceleration in a shock wave propagating to an inhomogeneous medium

Authors: Shota Yokoyama, Yutaka Ohira

Comments: 7 pages, 3 figures, Submitted to ApJ

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

We investigate effects of upstream density fluctuations on the diffusive shock acceleration by Monte Carlo simulations. The simulations show that particles are reaccelerated in the shock downstream region by a sound wave generated at the shock front. The time scale of turbulent acceleration by the sound wave is estimated. We propose a new back reaction of particles accelerated around the shock front. The accelerated particles generate the upstream density fluctuations by the Drury instability, which are converted to the downstream sound waves by the shock. The downstream sound waves modify the momentum spectrum of particles accelerated around the shock front. This new back reaction affects emission from the accelerated particles, which gives a new constraint on the acceleration efficiency of the diffusive shock acceleration.

[33]  arXiv:2004.05787 [pdf, other]

Title: The energetic thermonuclear bursts in SAX J1712.6-3739

Authors: Jie Lin, Wenfei Yu

Comments: 12 pages, 7 figures, submitted to ApJ

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

The neutron star low-mass X-ray binary SAX J1712.6-3739 is known for its very long and hard thermonuclear bursts in past X-ray observations. Its thermonuclear bursts are so energetic that they can even last for tens of minutes in the hard X-ray observations of Swift/BAT (E > 15 keV). For exploring the natures of SAX J1712.6-3739 and its thermonuclear bursts, we analyzed its four bursts which were all captured by Swift/BAT. The peak flux and fluence for these bursts are derived by applying the archive observation data of Swift/BAT and Swift/XRT. Based on the peak fluxes observed by Swift, the distance of SAX J1712.6-3739 is estimated as 4.6 kpc, which is much closer than the estimate by the BeppoSAX observations. The corresponding absolute magnitude and average accretion rate agree its ultra-compact X-ray binary nature. By the measurements of effective duration, we determined that the 2010 burst corresponds to a normal X-ray burst, the 2011 burst is consistent with an intermediate-duration burst while the 2014 and the 2018 bursts are more energetic than common intermediate-duration bursts but less energetic than superbursts. Since the average mass accretion rate of SAX J1712.6-3739 was only 0.6%M_Edd, and current theory predict no carbon production in the bursters under very low accretion rate. Therefore, the 2014 and the 2018 bursts are very likely to be deep helium bursts. In the Swift observations, SAX J1712.6-3739 has shown at least three different levels of duration in thermonuclear bursts. They were possibly induced by variable accretion rates, because their ignition column depths roughly follow the prediction of ignition models for pure helium bursts at corresponding accretion rates.

[34]  arXiv:2004.05797 [pdf, ps, other]

Title: Wave amplitude modulation in fan loops as observed by AIA/SDO

Authors: Aishawnnya Sharma, Durgesh Tripathi, Robertus Erdelyi, G. R. Gupta, G. A. Ahmed

Comments: Accepted for publication in Astronomy and Astrophysics

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

We perform multiwavelength time-distance analysis of a fan loop system anchored in an isolated sunspot region AR 12553. The active region was observed by the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory. We measure the phase speeds of the propagating intensity disturbances by employing cross-correlation analysis, as well as by obtaining the slopes in xt-plots. We obtain original as well as de-trended light curves at different heights of the time-distance maps and characterize them by performing Fouri\'er and Wavelet analysis, respectively. The time-distance maps reveal clear propagation of intensity oscillations in all the coronal EUV channels except AIA 94 and 335~{\AA}. We determine the nature of the intensity disturbances as slow magnetoacoustic waves by measuring their phase speeds. The time-distance maps, as well as the de-trended light curves, show an increase and decrease in the amplitude of propagating 3-min oscillations over time. The amplitude variations appear most prominent in AIA 171~{\AA}, though other EUV channels also show such signatures. Fouri\'er power spectrum yield the presence of significant powers with several nearby frequencies between 2--3 minutes (5--8 mHz), along with many other smaller peaks between 2--4 minutes. Wavelet analysis shows an increase and decrease of oscillating power around 3-min simultaneous to the amplitude variations. We obtain the modulation period to be in the range of 20--30 minutes. Our results provide the viability of occurrence of phenomenon like `Beat' among the nearby frequencies giving rise to the observed amplitude modulation. However, we cannot, at this stage, rule out the possibility that the modulation may be driven by variability of an underlying unknown source.

[35]  arXiv:2004.05818 [pdf, ps, other]

Title: The H$_2$O Spectrum of the Massive Protostar AFGL 2136 IRS 1 from 2 to 13 $μ$m at High Resolution: Probing the Circumstellar Disk

Authors: Nick Indriolo, D. A. Neufeld, A. G. Barr, A. C. A. Boogert, C. N. DeWitt, A. Karska, E. J. Montiel, M. J. Richter, A. G. G. M. Tielens

Comments: 30 pages, 12 figures, 3 tables, ApJ accepted

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

We have observed the massive protostar AFGL 2136 IRS 1 in multiple wavelength windows in the near-to-mid-infrared at high ($\sim3$ km s$^{-1}$) spectral resolution using VLT+CRIRES, SOFIA+EXES, and Gemini North+TEXES. There is an abundance of H$_2$O absorption lines from the $\nu_1$ and $\nu_3$ vibrational bands at 2.7 $\mu$m, from the $\nu_2$ vibrational band at 6.1 $\mu$m, and from pure rotational transitions near 10-13 $\mu$m. Analysis of state-specific column densities derived from the resolved absorption features reveals that an isothermal absorbing slab model is incapable of explaining the relative depths of different absorption features. In particular, the strongest absorption features are much weaker than expected, indicating optical depth effects resulting from the absorbing gas being well-mixed with the warm dust that serves as the "background" continuum source at all observed wavelengths. The velocity at which the strongest H$_2$O absorption occurs coincides with the velocity centroid along the minor axis of the compact disk in Keplerian rotation recently observed in H$_2$O emission with ALMA. We postulate that the warm regions of this dust disk dominate the continuum emission at near-to-mid infrared wavelengths, and that H$_2$O and several other molecules observed in absorption are probing this disk. Absorption line profiles are not symmetric, possibly indicating that the warm dust in the disk that produces the infrared continuum has a non-uniform distribution similar to the substructure observed in 1.3 mm continuum emission.

[36]  arXiv:2004.05840 [pdf, other]

Title: An extremely energetic supernova from a very massive star in a dense medium

Authors: Matt Nicholl, Peter K. Blanchard, Edo Berger, Ryan Chornock, Raffaella Margutti, Sebastian Gomez, Ragnhild Lunnan, Adam A. Miller, Wen-fai Fong, Giacomo Terreran, Alejandro Vigna-Gomez, Kornpob Bhirombhakdi, Allyson Bieryla, Pete Challis, Russ R. Laher, Frank J. Masci, Kerry Paterson

Comments: Published in Nature Astronomy, 13 April 2020

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

The interaction of a supernova with a circumstellar medium (CSM) can dramatically increase the emitted luminosity by converting kinetic energy to thermal energy. In 'superluminous' supernovae (SLSNe) of Type IIn -- named for narrow hydrogen lines in their spectra -- the integrated emission can reach $\sim 10^{51}$ erg, attainable by thermalising most of the kinetic energy of a conventional SN. A few transients in the centres of active galaxies have shown similar spectra and even larger energies, but are difficult to distinguish from accretion onto the supermassive black hole. Here we present a new event, SN2016aps, offset from the centre of a low-mass galaxy, that radiated $\gtrsim 5 \times 10^{51}$ erg, necessitating a hyper-energetic supernova explosion. We find a total (SN ejecta $+$ CSM) mass likely exceeding 50-100 M$_\odot$, with energy $\gtrsim 10^{52}$ erg, consistent with some models of pair-instability supernovae (PISNe) or pulsational PISNe -- theoretically-predicted thermonuclear explosions from helium cores $>50$ M$_\odot$. Independent of the explosion mechanism, this event demonstrates the existence of extremely energetic stellar explosions, detectable at very high redshifts, and provides insight into dense CSM formation in the most massive stars.

[37]  arXiv:2004.05888 [pdf, ps, other]

Title: Properties of environment around AGN and luminous galaxy pairs through HSC wide survey

Authors: Yuji Shirasaki, Masayuki Akiyama, Yoshiki Toba, Wanqiu He, Tomotsugu Goto

Comments: 46 pages, 21 figures, accepted for publication in PASJ

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

We investigated the properties of AGN environments, particularly environments where the association of luminous galaxies (LGs) is found within 4~Mpc from AGNs with redshifts of 0.8 -- 1.1. For comparison, three additional AGN environments, (namely, AGNs of all types, type~1 AGNs with X-ray and/or radio detection, and type~2 AGNs) and an environment of blue $M_{*}$, characteristic luminosity of the Schechter function, galaxies were investigated. The cross-correlation function with the surrounding galaxies was measured and compared between the AGN and blue galaxy samples. We also compared the distributions of color, absolute magnitude, and stellar mass of the galaxies around such target objects. The properties of clusters detected using surrounding galaxies selected based on a photometric redshift were examined and compared for different samples. The target AGNs were drawn from the Million Quasars (MILLIQUAS) catalog, and the blue galaxies were drawn from six redshift survey catalogs (SDSS, WiggleZ, DEEP2, VVDS, VIPERS, and PRIMUS). The galaxies used as a measure of the environment around the targets are drawn from S18a internal data released by the Hyper Suprime-Cam Subaru Strategic Program (HSC-SSP). We found that, among the five AGN and blue galaxy samples considered, the environment of AGN-LG pairs is the most enriched with luminous galaxies. We also found an enhancement in the number of mass-selected clusters in the AGN-LG pair sample against those in the other samples. The results obtained in this study indicate that existence of multiple clusters is the major driver in the association of AGNs and LGs, rather than a single large-mass dark matter halo hosting the AGN.

[38]  arXiv:2004.05905 [pdf, other]

Title: Relativistic corrections to the rotation curves of disk galaxies

Authors: Alexandre Deur

Comments: 7 pages, 6 figures

Subjects: Astrophysics of Galaxies (astro-ph.GA); General Relativity and Quantum Cosmology (gr-qc)

We present a method to investigate the effect of relativistic corrections arising from large masses to the rotation curves of disk galaxies. The method employs a mean-field approximation and gravitational lensing. Applying it to a basic model of disk galaxy, we find that these corrections become important and magnified at large distances. The magnitude of the effect is sufficient to explain the galactic missing mass problem without requiring a significant amount of dark matter. A prediction of the model is that there should be a strong correlation between the inferred galactic dark mass and the galactic disk thickness. We use two independent sets of data to verify this.

[39]  arXiv:2004.05941 [pdf, other]

Title: The broad-line type Ic SN 2020bvc: signatures of an off-axis gamma-ray burst afterglow

Authors: L. Izzo, K. Auchettl, J. Hjorth, F. De Colle, C. Gall, C. R. Angus, S. I. Raimundo, E. Ramirez-Ruiz

Comments: 6 pages, 5 figures

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

Long-duration gamma-ray bursts (GRBs) are almost unequivocally associated with very energetic, broad-lined supernovae (SNe) of Type Ic-BL. While the gamma-ray emission is emitted in narrow jets, the SN emits radiation isotropically. Therefore, some SN Ic-BL not associated with GRBs have been hypothesised to arise from events with inner engines such as off-axis GRBs or choked jets. Here we present observations of the nearby ($d = 120$ Mpc) SN 2020bvc (ASAS-SN 20bs) which provide direct and compelling evidence for this scenario. \textit{Swift} UVOT observations reveal an early decline (up to two days after explosion) while optical spectra classify it as a SN Ic-BL with very high expansion velocities ($\approx$ 70,000 km/s), similar to that found for the jet-cocoon emission in SN 2017iuk associated with GRB 171205A. Moreover, decaying \textit{Swift} X-Ray Telescope and \textit{Chandra} X-ray Observatory X-ray emission is detected (from three days and onwards), attributable to an afterglow component. Cocoon and X-ray emission are both signatures of jet-powered GRBs. In the case of SN 2020bvc, we find that the jet is off axis (by $\approx$23 degrees) as indicated by the lack of early ($\approx 1$ day) X-ray emission which explains why no coincident GRB was detected promptly or in archival data. Thus, SN 2020bvc is the first orphan GRB detected through its associated SN emission.

[40]  arXiv:2004.05947 [pdf, other]

Title: Delta-doped Electron Multiplying CCDs for FIREBall-2

Authors: Gillian Kyne, Erika T. Hamden, Shouleh Nikzad, Keri Hoadley, April Jewell, Todd Jones, Michael Hoenk, Samuel Cheng, D. Christopher Martin, Nicole Lingner, David Schiminovich, Bruno Milliard, Robert Grange, Olivier Daigle

Comments: 36 pages, 9 figures

Journal-ref: J. Astron. Telesc. Instrum. Syst. 6(1), 011007 (2020)

Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Instrumentation and Detectors (physics.ins-det)

We present the status of on-going detector development efforts for our joint NASA/CNES balloon-borne UV multi-object spectrograph, the Faint Intergalactic Redshifted Emission Balloon (FIREBall-2; FB-2). FB-2 demonstrates a new UV detector technology, the delta-doped Electron Multiplying CCD (EMCCD), in a low risk suborbital environment, to prove the performance of EMCCDs for future space missions and Technology Readiness Level (TRL) advancement. EMCCDs can be used in photon counting (PC) mode to achieve extremely low readout noise ($<$1 electron). Our testing has focused on reducing clock-induced-charge (CIC) through wave shaping and well depth optimization with a \nuvu V2 CCCP Controller, measuring CIC at 0.001 e$^{-}$/pixel/frame. This optimization also includes methods for reducing dark current, via cooling, and substrate voltage levels. We discuss the challenges of removing cosmic rays, which are also amplified by these detectors, as well as a data reduction pipeline designed for our noise measurement objectives. FB-2 flew in 2018, providing the first time an EMCCD was used for UV observations in the stratosphere. FB-2 is currently being built up to fly again in 2020, and improvements are being made to the EMCCD to continue optimizing its performance for better noise control.

[41]  arXiv:2004.05952 [pdf, other]

Title: Systematic vs. Statistical Uncertainties in Masses and Magnifications of the Hubble Frontier Fields

Authors: Catie A Raney, Charles R Keeton, Sean Brennan, Hsin Fan

Comments: 25 pages, 21 figures. Accepted for publication in MNRAS

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

The Hubble Frontier Fields data, along with multiple data sets obtained by other telescopes, have provided some of the most extensive constraints on cluster lenses to date. Multiple lens modeling teams analyzed the fields and made public a number of deliverables. By comparing these results, we can then undertake a unique and vital test of the state of cluster lens modeling. Specifically, we see how well the different teams can reproduce similar magnifications and mass profiles. We find that the circularly averaged mass profiles of the fields are remarkably constrained (scatter <5%) at distances of 1 arcmin from the cluster core, yet magnifications can vary significantly. Averaged across the six fields, we find a bias of -6% (-17%) and a scatter of ~40% (~65%) at a modest magnification of 3 (10). Statistical errors reported by individual teams are often significantly smaller than the differences among all the teams, indicating the importance of continued systematics studies in cluster lensing.

[42]  arXiv:2004.05957 [pdf, ps, other]

Title: Age and chemical composition of the globular cluster NGC 6652

Authors: M.E. Sharina (SAO RAS), V.V. Shimansky (Kazan Federal University)

Comments: Research in Astronomy and Astrophysics, accepted

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

We present the results of determination of the age, helium mass fraction (Y), metallicity ([Fe/H]), and abundances of the elements C, N, O, Na, Mg, Ca, Ti, C, and Mn for the Galactic globular cluster NGC 6652. We use its medium-resolution integrated-light spectrum from the library of Schiavon and our population synthesis method to fulfill this task. We select for our analysis the evolutionary isochrone and stellar mass function which provide the best approximation of the shapes and intensities of the observed Balmer line profiles. The determined elemental abundances, age and metallicity are characteristic of stellar populations of the Galactic Bulge.

[43]  arXiv:2004.05982 [pdf, ps, other]

Title: The explosive life of massive binaries

Authors: Mathieu Renzo, Emmanouil Zapartas

Comments: proceedings of the conference "Universe of binaries, binaries in the Universe" held in Telc in Sep, 2019

Journal-ref: https://www.astro.sk/caosp/Eedition/Abstracts/2020/Vol_50/No_2/index.html

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

Massive stars are born predominantly as members of binary (or higher multiplicity) systems, and the presence of a companion can significantly alter their life and final fate. Therefore, any observed sample of massive stars or associated transients is likely to be significantly influenced by the effects of binarity. Here, we focus on the relationship between massive binary evolution and core-collapse supernova events. In the vast majority of the cases, the first core-collapse event happening in a binary system unbinds the two stars. Studying the population of companion stars, either at the supernova site, or as "widowed" stars long after the explosion, can be used to constrain the previous orbital evolution of the binary progenitor, and explosion physics of their former companion. Specifically, the population of "widowed" stars might provide statistical constraints on the typical amplitude of black hole natal kicks without seeing neither the black holes nor the transient possibly associated with their formation. Binarity also has a large impact on the predicted population of supernova sub-types, including hydrogen-rich type II supernovae, with a significant fraction of hydrogen-rich stars at explosions being either merger products or accretors.

[44]  arXiv:2004.06008 [pdf, other]

Title: Cosmological simulations of the same spiral galaxy: the impact of baryonic physics

Authors: Arturo Nuñez-Castiñeyra, Emmanuel Nezri, Julien Devriendt, Romain Teyssier

Comments: 17 pages, 10 figures

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

The interplay of star formation and supernova (SN) feedback in galaxy formation is a key element for understanding galaxy evolution. Since these processes occur at small scales, it is necessary to have sub-grid models that recover their evolution and environmental effects at the scales reached by cosmological simulations. We simulate the same spiral galaxy inhabiting a Milky Way (MW) size halo in a cosmological environment changing the sub-grid models for SN feedback and star formation. We test combinations of the Schmidt law and a multi-freefall based star formation with delayed cooling feedback or mechanical feedback. We reach a resolution of 35 pc in a zoom-in box of 36 Mpc. For this, we use the code RAMSES with the implementation of gas turbulence in time and trace the local hydrodynamical features of the star-forming gas. Finally, we compare the galaxies at redshift 0 with global and interstellar medium observations in the MW and local spiral galaxies. The simulations show successful comparisons with observations. Nevertheless, diverse galactic morphologies are obtained from different numerical implementations. We highlight the importance of detailed modelling of the star formation and feedback processes, especially when increasing the resolution of simulations. Future improvements could alleviate the degeneracies exhibited in our simulated galaxies under different sub-grid models.

[45]  arXiv:2004.06027 [pdf, ps, other]

Title: The Gemini Planet Imager view of the HD 32297 debris disk

Authors: Gaspard Duchene, Malena Rice, Justin Hom, Joseph Zalesky, Thomas M. Esposito, Maxwell A. Millar-Blanchaer, Bin Ren, Paul Kalas, Michael Fitzgerald, Pauline Arriaga, Sebastian Bruzzone, Joanna Bulger, Christine H. Chen, Eugene Chiang, Tara Cotten, Ian Czekala, Robert J. De Rosa, Ruobing Dong, Zachary H. Draper, Katherine B. Follette, James R. Graham, Li-Wei Hung, Ronald Lopez, Bruce Macintosh, Brenda C. Matthews, Johan Mazoyer, Stan Metchev, Jennifer Patience, Marshall D. Perrin, Julien Rameau, Inseok Song, Kevin Stahl, Jason Wang, Schuyler Wolff, Ben Zuckerman, S. Mark Ammons, Vanessa P. Bailey, Travis Barman, Jeffrey Chilcote, Rene Doyon, Benjamin L. Gerard, Stephen J. Goodsell, Alexandra Z. Greenbaum, Pascale Hibon, Patrick Ingraham, Quinn Konopacky, Jerome Maire, Franck Marchis, Mark S. Marley, et al. (14 additional authors not shown)

Comments: Accepted for publication in the Astronomical Journal

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

We present new $H$-band scattered light images of the HD 32297 edge-on debris disk obtained with the Gemini Planet Imager (GPI). The disk is detected in total and polarized intensity down to a projected angular separation of 0.15", or 20au. On the other hand, the large scale swept-back halo remains undetected, likely a consequence of its markedly blue color relative to the parent body belt. We analyze the curvature of the disk spine and estimate a radius of $\approx$100au for the parent body belt, smaller than past scattered light studies but consistent with thermal emission maps of the system. We employ three different flux-preserving post-processing methods to suppress the residual starlight and evaluate the surface brightness and polarization profile along the disk spine. Unlike past studies of the system, our high fidelity images reveal the disk to be highly symmetric and devoid of morphological and surface brightness perturbations. We find the dust scattering properties of the system to be consistent with those observed in other debris disks, with the exception of HR 4796. Finally, we find no direct evidence for the presence of a planetary-mass object in the system.

[46]  arXiv:2004.06041 [pdf, other]

Title: Foreground modelling via Gaussian process regression: an application to HERA data

Authors: Abhik Ghosh, Florent Mertens, Gianni Bernardi, Mário G. Santos, Nicholas S. Kern, Christopher L. Carilli, Trienko L. Grobler, Léon V. E. Koopmans, Daniel C. Jacobs, Adrian Liu, Aaron R. Parsons, Miguel F. Morales, James E. Aguirre, Joshua S. Dillon, Bryna J. Hazelton, Oleg M. Smirnov, Bharat K. Gehlot, Siyanda Matika, Paul Alexander, Zaki S. Ali, Adam P. Beardsley, Roshan K. Benefo, Tashalee S. Billings, Judd D. Bowman, Richard F. Bradley, Carina Cheng, Paul M. Chichura, David R. DeBoer, Eloy de Lera Acedo, Aaron Ewall-Wice, Gcobisa Fadana, Nicolas Fagnoni, Austin F. Fortino, Randall Fritz, Steve R. Furlanetto, Samavarti Gallardo, Brian Glendenning, Deepthi Gorthi, Bradley Greig, Jasper Grobbelaar, Jack Hickish, Alec Josaitis, Austin Julius, Amy S. Igarashi, MacCalvin Kariseb, Saul A. Kohn, et al. (27 additional authors not shown)

Comments: 13 pages, 14 figures, 1 table, Submitted to MNRAS

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

The key challenge in the observation of the redshifted 21-cm signal from cosmic reionization is its separation from the much brighter foreground emission. Such separation relies on the different spectral properties of the two components, however, the foreground intrinsic spectral smoothness is often corrupted by the instrumental response making such separation much harder. In this paper, we apply Gaussian Process Regression to model the foreground emission using $\sim 2$ hours of data from the Hydrogen Epoch of Reionization Array. We find that a simple co-variance model with three components matches the data well, the residual being noise like. These consist of an "intrinsic" and instrumentally corrupted component with a coherence-scale of 20 MHz and 2.4 MHz respectively (dominating the line of sight power spectrum over scales $k_{\parallel} \le 0.2 \, $hcMpc$^{-1}$) and a baseline dependent periodic signal with a period of $\sim$ 1 MHz (dominating over $k_{\parallel} \sim 0.4 - 0.8 \, $hcMpc$^{-1}$) which should be distinguishable from the 21-cm EoR signal whose typical coherence-scales is $\sim 0.8$ MHz.

[47]  arXiv:2004.06078 [pdf, other]

Title: NS 1987A in SN 1987A

Authors: Dany Page, Mikhail V. Beznogov, Iván Garibay, James M. Lattimer, Madappa Prakash, Hans-Thomas Janka

Comments: 17 page, 7 figures, submitted to Ap.J

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)

The possible detection of a compact object in the remnant of SN 1987A presents an unprecedented opportunity to follow its early evolution. The suspected detection stems from an excess of infrared emission from a dust blob near the compact object's predicted position. The infrared excess could be due to the decay of isotopes like 44Ti, accretion luminosity from a neutron star or black hole, magnetospheric emission or a wind originating from the spindown of a pulsar, or to thermal emission from an embedded, cooling neutron star (NS 1987A). It is shown that the latter possibility is the most plausible as the other explanations are disfavored by other observations and/or require fine-tuning of parameters. Not only are there indications the dust blob overlaps the predicted location of a kicked compact remnant, but its excess luminosity also matches the expected thermal power of a 30 year old neutron star. Furthermore, models of cooling neutron stars within the Minimal Cooling paradigm readily fit both NS 1987A and Cas A, the next-youngest known neutron star. If correct, NS 1987A likely has a light-element envelope and a relatively small crustal n-1S0 superfluid gap. If the locations don't overlap, then pulsar spindown or accretion might be more likely, but the pulsar's period and magnetic field or the accretion rate must be rather finely tuned. In this case, NS 1987A may have enhanced cooling and/or a heavy-element envelope.

[48]  arXiv:2004.06082 [pdf, other]

Title: Simultaneous X-ray and Radio Observations of the Repeating Fast Radio Burst FRB 180916.J0158+65

Authors: P. Scholz, A. Cook, M. Cruces, J. W. T. Hessels, V. M. Kaspi, W. A. Majid, A. Naidu, A. B. Pearlman, L. Spitler, K. M. Bandura, M. Bhardwaj, T. Cassanelli, P. Chawla, B. M. Gaensler, D. C. Good, A. Josephy, R. Karuppusamy, A. Keimpema, A. Yu. Kirichenko, F. Kirsten, J. Kocz, C. Leung, B. Marcote, K. Masui, J. Mena-Parra, M. Merryfield, D. Michilli, C. J. Naudet, K. Nimmo, Z. Pleunis, T. A. Prince, M. Rafiei-Ravandi, M. Rahman, K. Shin, K. M. Smith, I. H. Stairs, S. P. Tendulkar, K. Vanderlinde

Comments: 16 pages, 2 figures, submitted to ApJ

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

We report on simultaneous radio and X-ray observations of the repeating fast radio burst source FRB 180916.J0158+65 using the Canadian Hydrogen Intensity Mapping Experiment (CHIME), Effelsberg, and Deep Space Network (DSS-14 and DSS-63) radio telescopes and the Chandra X-ray Observatory. During 33 ks of Chandra observations, we detect no radio bursts in overlapping Effelsberg or Deep Space Network observations and a single radio burst during CHIME/FRB source transits. We detect no X-ray events in excess of the background during the Chandra observations. These non-detections imply a 5-$\sigma$ limit of $<5\times10^{-10}$ erg cm$^{-2}$ for the 0.5--10 keV fluence of prompt emission at the time of the radio burst and $1.3\times10^{-9}$ erg cm$^{-2}$ at any time during the Chandra observations at the position of FRB 180916.J0158+65. Given the host-galaxy redshift of FRB 180916.J0158+65 ($z\sim0.034$), these correspond to energy limits of $<1.6\times10^{45}$ erg and $<4\times10^{45}$ erg, respectively. We also place a 5-$\sigma$ limit of $<8\times10^{-15}$ erg s$^{-1}$ cm$^{-2}$ on the 0.5--10\,keV absorbed flux of a persistent source at the location of FRB 180916.J0158+65. This corresponds to a luminosity limit of $<2\times10^{40}$ erg s$^{-1}$. Using Fermi/GBM data we search for prompt gamma-ray emission at the time of radio bursts from FRB 180916.J0158+65 and find no significant bursts, placing a limit of $4\times10^{-9}$ erg cm$^{-2}$ on the 10--100 keV fluence. We also search Fermi/LAT data for periodic modulation of the gamma-ray brightness at the 16.35-day period of radio-burst activity and detect no significant modulation. We compare these deep limits to the predictions of various fast radio burst models, but conclude that similar X-ray constraints on a closer fast radio burst source would be needed to strongly constrain theory.

[49]  arXiv:2004.06083 [pdf, other]

Title: The Fates of Merging Supermassive Black Holes and a Proposal for a New Class of X-Ray Sources

Authors: Charles Zivancev, Jeremiah Ostriker, Andreas H.W. Kupper

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

We perform N-body simulations on some of the most massive galaxies extracted from a cosmological simulation of hierarchical structure formation with total masses in the range $10^{12} M_{\odot} < M_{tot} < 3\times 10^{13} M_{\odot}$ from $4\geq z \geq 0$. After galactic mergers, we track the dynamical evolution of the infalling black holes (BHs) around their host's central BHs. From 11 different simulations, we find that, of the 86 infalling BHs with masses > $10^4 M_{\odot}$, 36 merge with their host's central BH, 13 are ejected from their host galaxy, and 37 are still orbiting at $z=0$. Across all galaxies, 33 BHs are kicked to a higher orbit after close interactions with the central BH binary or multiple, after which only one of them merged with their hosts. These orbiting BHs should be detectable by their anomalous (not Low Mass X-ray Binary) spectra. The X-ray luminosities of the orbiting massive BHs at z=0 are in the range $10^{28}-10^{43}$ $\mathrm{erg}~\mathrm{s}^{-1}$, with a currently undetectable median value of $10^{33}$ $\mathrm{erg}~\mathrm{s}^{-1}$. However, the most luminous $\sim$5\% should be detectable by existing X-ray facilities.

[50]  arXiv:2004.06086 [pdf, ps, other]

Title: Time sequence spectroscopy of Epsilon CrA. The 518 nm Mg I triplet region analyzed with Broadening Functions

Authors: Slavek M. Rucinski (Department of Astronomy and Astrophysics, University of Toronto)

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

High-resolution spectroscopic observations of the W UMa-type binary Epsilon CrA obtained as a time monitoring sequence on four full and four partial nights within two weeks have been used to derive orbital elements of the system and discuss the validity of the Lucy model for description of the radial-velocity data. The observations had more extensive temporal coverage and better quality than similar time-sequence observations of the contact binary AW UMa. The two binaries share several physical properties with both showing very similar deviations from the Lucy model: The primary component is a rapidly-rotating star almost unaffected by the presence of the secondary component, while the latter is embedded in a complex gas flow and appears to have its own rotation-velocity field, in contradiction to the model. The spectroscopic mass ratio is found to be larger than the one derived from the light-curve analysis, similarly as in many other W UMa-type binaries, but this discrepancy for Epsilon CrA is relatively minor suggesting a systematic problem with one of the observational methods commonly affecting other determinations. The presence of the complex velocity flows contradicting the solid-body rotation assumption suggest a necessity of modification to the Lucy model, possibly along the lines outlined by Stepien (2009) in his concept of the energy transfer between the binary components.

[51]  arXiv:2004.06105 [pdf, other]

Title: A systematic study of galactic outflows via fluorescence emission: implications for their size and structure

Authors: Bingjie Wang, Timothy M. Heckman, Guangtun Zhu, Colin A. Norman

Comments: 23 pages, 11 figures, 6 tables; accepted for publication in ApJ

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

Galactic outflows play a major role in the evolution of galaxies, but the underlying physical processes are poorly understood. This is mainly because we have little information about the outflow structure, especially on large scales. In this paper, we probe the structure of galactic outflows in low-$z$ starburst by using a combination of ultra-violet spectroscopy and imaging of the fluorescence emission lines (associated with transitions to excited fine-structure levels) and spectroscopy of the corresponding strongly blue-shifted resonance absorption lines. We find that in the majority of cases the observed fluorescence emission lines are much weaker and narrower than the absorption lines, originating in the star-forming interstellar medium and/or the slowest-moving part of the inner outflow. In a minority of cases, the outflowing absorbing material does make a significant contribution to the fluorescence emission. These latter systems are characterized by both strong Ly$\alpha$ emission lines and weak low-ionization absorption lines (both known to be empirical signs of Lyman-continuum leakage). We argue that the observed weakness of emission from the outflow seen in the majority of cases is due to the missing emission arising on scales larger than those encompassed by the aperture of the {\it{Hubble Space Telescope}}. This implies shallow radial density profiles in these outflows, and suggests that most of the observed absorbing material must be created/injected at radii much larger than that of the starburst. This has important implications for our understanding of both the physics of galactic outflows and for our estimation of their principal properties.

[52]  arXiv:2004.06106 [pdf, other]

Title: Seeding primordial black holes in multi-field inflation

Authors: Gonzalo A. Palma, Spyros Sypsas, Cristobal Zenteno

Comments: 7 pages, 1 figure

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

The inflationary origin of primordial black holes (PBHs) relies on a large enhancement of the power spectrum $\Delta_\zeta$ of the curvature fluctuation $\zeta$ at wavelengths much shorter than those of the cosmic microwave background anisotropies. This is typically achieved in models where $\zeta$ evolves without interacting significantly with additional (isocurvature) scalar degrees of freedom. However, quantum gravity inspired models are characterized by moduli spaces with highly curved geometries and a large number of scalar fields that could vigorously interact with $\zeta$ (as in the cosmological collider picture). Here we show that isocurvature fluctuations can mix with $\zeta$ inducing large enhancements of its amplitude. This occurs whenever the inflationary trajectory experiences rapid turns in the field space of the model leading to amplifications that are exponentially sensitive to the total angle swept by the turn, which induce characteristic observable signatures on $\Delta_\zeta$. We derive accurate analytical predictions and show that the large enhancements required for PBHs demand non-canonical kinetic terms in the action of the multi-field system.

Cross-lists for Tue, 14 Apr 20

[53]  arXiv:2004.04740 (cross-list from hep-ph) [pdf, other]

Title: Dark matter and dark radiation from evaporating primordial black holes

Authors: Isabella Masina

Comments: 29 pages, 9 figures

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

Primordial black holes in the mass range from $0.1$ to $10^9$ g might have existed in the early universe. Via their evaporation mechanism (completed before Big Bang Nucleosynthesis), they might have released stable particles beyond the Standard Model. We reconsider the possibility that such particles might constitute the main part or a fraction of the dark matter observed today, updating the impact on this scenario from warm dark matter constraints. If sufficiently light, stable particles from primordial black holes evaporation might also provide a significant contribution to dark radiation. We generalize previous studies on this interesting dark matter and dark radiation production mechanism, by including the effects of accretion and a possible amount of entropy non conservation. We also discuss in some detail specific examples of stable particle candidates beyond the Standard Model.

[54]  arXiv:2004.05165 (cross-list from hep-ph) [pdf, other]

Title: Cosmic Gamma Ray Constraints on the Indirect Effects of Dark Matter

Authors: Konstantin M. Belotsky, Airat Kh. Kamaletdinov, Ekaterina S. Shlepkina, Maxim L. Solovyov

Comments: The article was published in MDPI "Particle". The authors used to the article structure suggested by the journal (MDPI "Particles")

Journal-ref: Particles 2020, 3, 336-344

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

The observed anomalous excess of high-energy cosmic ray (CR) positrons is widely discussed as possible indirect evidence for dark matter (DM). However, any source of cosmic positrons is inevitably the source of gamma radiation. The least model dependent test of CR anomalies interpretation via DM particles decays (or annihilation) is connected with gamma-ray background due to gamma overproduction in such processes. In this work, we impose an observational constraint on gamma ray production from DM. Then, we study the possible suppression of gamma yield in the DM decays into identical final fermions. Such DM particles arise in the multi-component dark atom model. The influence of the interaction vertices on the gamma suppression was also considered. No essential gamma suppression effects are found. However, some minor ones are revealed.

[55]  arXiv:2004.05178 (cross-list from gr-qc) [pdf, other]

Title: Evolution of black hole shadows from superradiance

Authors: Gastón Creci, Stefan Vandoren, Helvi Witek

Comments: 22 pages, 16 figures

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

Black holes have turned into cosmic laboratories to search for ultra-light scalars by virtue of the superradiant instability. In this paper we present a detailed study of the impact of the superradiant evolution on the black hole shadow and investigate the exciting possibility to explore it with future observations of Very Long Baseline Interferometry. We simulated the superradiant evolution numerically, in the adiabatic regime, and derived analytic approximations modelling the process. Driven by superradiance, we evolve the black hole shadow diameter and (i) find that it can change by a few $\mu$as, just below the current resolution of the Event Horizon Telescope, albeit on timescales that are longer than realistic observation times; (ii) show that the shadow diameter can either shrink or grow; and (iii) explore in detail how the shadow's end state is determined by the initial parameters and coupling.

[56]  arXiv:2004.05354 (cross-list from hep-ph) [pdf, ps, other]

Title: Supersymmetric Clockwork Axion Model and Axino Dark Matter

Authors: Kyu Jung Bae, Sang Hui Im

Comments: 9 pages

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

Implications of supersymmetrizing the clockwork axions are stuided. Supersymmetry ensures that the saxions and axinos have the same pattern of the coupling hierarchy as the clockwork axions. If we assume supersymmetry breaking is universal over the the clockwork sites, the coupling structure is preserved, while the mass orderings of the saxions and axinos can differ depending on the supersymmetry breaking scale. While the massive saxions and axions quickly decay, the lightest axino can be stable and thus a dark matter candidate. The relic abundance of the axino dark matter from thermal production is mostly determined by decays of the heavier axinos in the normal mass ordering. This exponentially enhances the thermal yield compared to the conventional axino scenarios. Some cosmological issues are discussed.

[57]  arXiv:2004.05374 (cross-list from stat.ME) [pdf, other]

Title: Handling missing data in a neural network approach for the identification of charged particles in a multilayer detector

Authors: S. Riggi, D. Riggi, F. Riggi

Comments: 14 pages, 8 figures

Journal-ref: Nucl. Instr. and Methods in Physics Research A 780 (2015) 81-90

Subjects: Methodology (stat.ME); Instrumentation and Methods for Astrophysics (astro-ph.IM); Data Analysis, Statistics and Probability (physics.data-an); Instrumentation and Detectors (physics.ins-det); Applications (stat.AP)

Identification of charged particles in a multilayer detector by the energy loss technique may also be achieved by the use of a neural network. The performance of the network becomes worse when a large fraction of information is missing, for instance due to detector inefficiencies. Algorithms which provide a way to impute missing information have been developed over the past years. Among the various approaches, we focused on normal mixtures models in comparison with standard mean imputation and multiple imputation methods. Further, to account for the intrinsic asymmetry of the energy loss data, we considered skew-normal mixture models and provided a closed form implementation in the Expectation-Maximization (EM) algorithm framework to handle missing patterns. The method has been applied to a test case where the energy losses of pions, kaons and protons in a six-layers Silicon detector are considered as input neurons to a neural network. Results are given in terms of reconstruction efficiency and purity of the various species in different momentum bins.

[58]  arXiv:2004.05449 (cross-list from physics.space-ph) [pdf, other]

Title: The Evolution of Inverted Magnetic Fields Through the Inner Heliosphere

Authors: Allan Macneil, Mathew Owens, Robert Wicks, Mike Lockwood, Sarah Bentley, Mathew Lang

Comments: Accepted to Monthly Notices of the Royal Astronomical Society

Subjects: Space Physics (physics.space-ph); Solar and Stellar Astrophysics (astro-ph.SR)

Local inversions are often observed in the heliospheric magnetic field (HMF), but their origins and evolution are not yet fully understood.Parker Solar Probe has recently observed rapid, Alfvenic, HMF inversions in the inner heliosphere, known as 'switchbacks', which have been interpreted as the possible remnants of coronal jets. It has also been suggested that inverted HMF may be produced by near-Sun interchange reconnection; a key process in mechanisms proposed for slow solar wind release. These cases suggest that the source of inverted HMF is near the Sun, and it follows that these inversions would gradually decay and straighten as they propagate out through the heliosphere. Alternatively, HMF inversions could form during solar wind transit, through phenomena such velocity shears, draping over ejecta, or waves and turbulence. Such processes are expected to lead to a qualitatively radial evolution of inverted HMF structures. Using Helios measurements spanning 0.3-1 AU, we examine the occurrence rate of inverted HMF, as well as other magnetic field morphologies, as a function of radial distance A, and find that it continually increases. This trend may be explained by inverted HMF observed between 0.3-1 AU being primarily driven by one or more of the above in-transit processes, rather than created at the Sun. We make suggestions as to the relative importance of these different processes based on the evolution of the magnetic field properties associated with inverted HMF. We also explore alternative explanations outside of our suggested driving processes which may lead to the observed trend.

[59]  arXiv:2004.05489 (cross-list from hep-ph) [pdf, other]

Title: The cosmological constant and Higgs mass with emergent gauge symmetries

Authors: Steven D. Bass, Janina Krzysiak

Comments: 16 pages, 4 figures, presented at the XXVI Cracow Epiphany Conference on LHC Physics: Standard Model and Beyond, January 7-10 2020

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

We discuss the Higgs mass and cosmological constant in the context of an emergent Standard Model, where the gauge symmetries "dissolve" in the extreme ultraviolet. In this scenario the cosmological constant scale is suppressed by power of the large scale of emergence and expected to be of similar size to neutrino masses. Cosmology constraints then give an anthropic upper bound on the Higgs mass.

[60]  arXiv:2004.05590 (cross-list from gr-qc) [pdf]

Title: Mid-Frequency Gravitational Wave Detection and Sources

Authors: Wei-Tou Ni

Comments: 9 pages, adapted from FOREWORD to a 2020 IJMPD Special Issue on Mid-Frequency Gravitational Wave Detection and Sources

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

A brief history and various themes of mid-frequency gravitational wave detection are presented more or less following historical order -- Laser Interferometry, Atom Interferometry (AI), Torsion Bar Antenna (TOBA), and Superconducting Omni-directional Gravitational Radiation Observatory (SOGRO). Both Earth-based and Space-borne concepts are reviewed with outlook on expected astrophysical sources

[61]  arXiv:2004.05627 (cross-list from gr-qc) [pdf, other]

Title: Dynamical modelling of disc vertical structure in superthin galaxy `UGC 7321' in braneworld gravity: An MCMC study

Authors: K. Aditya, Indrani Banerjee, Arunima Banerjee, Soumitra SenGupta

Comments: 20 pages, 2 figures

Subjects: General Relativity and Quantum Cosmology (gr-qc); Astrophysics of Galaxies (astro-ph.GA)

Low surface brightness (LSBs) superthins constitute classic examples of very late-type galaxies, with their disc dynamics strongly regulated by their dark matter halos. In this work we consider a gravitational origin of dark matter in the brane world scenario, where the higher dimensional Weyl stress term projected onto the 3-brane acts as the source of dark matter. In the context of the braneworld model, this dark matter is referred to as the \emph{`dark mass'}.This model has been successful in reproducing the rotation curves of several low surface brightness and high surface brightness galaxies. Therefore it is interesting to study the prospect of this model in explaining the vertical structure of galaxies which has not been explored in the literature so far. Using our 2-component model of gravitationally-coupled stars and gas in the external force field of this \emph{dark mass}, we fit the observed scale heights of stellar and atomic hydrogen (HI) gas of superthin galaxy `UGC7321' using the Markov Chain Monte Carlo approach. We find that the observed scaleheights of `UGC7321' can be successfully modelled in the context of the braneworld scenario. In addition, the model predicted rotation curve also matches the observed one. The implications on the model parameters are discussed.

[62]  arXiv:2004.06058 (cross-list from gr-qc) [pdf, ps, other]

Title: Cosmological Dark Matter Amplification through Dark Torsion

Authors: Fernando Izaurieta, Samuel Lepe

Comments: 10 pages

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

A cosmological approach based on considering a cosmic background with non-zero torsion is shown in order to give an option of explaining a possible phantom evolution, not ruled out according to the current observational data. We revise some aspects of the formal schemes on torsion and, according them, we develop a formalism which can be an interesting alternative for exploring Cosmology.

[63]  arXiv:2004.06102 (cross-list from gr-qc) [pdf, other]

Title: Joint tests of cosmology and modified gravity in light of GW170817

Authors: S. Mastrogiovanni, D. A. Steer, M. Barsuglia

Comments: 3 figures, 2 tables

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

In this Letter we constrain for the first time both cosmology and modified gravity theories conjointly, by combining the GW and electromagnetic observations of GW170817. We provide joint posterior distributions for the Hubble constant $H_0$, and two physical effects typical of modified gravity: the gravitational wave (GW) friction, encoded by the parameter $\alpha_M$, and several GW dispersion relations. Among the results of this analysis, we can improve by 15\% the bound of the graviton mass with respect to measurement using the same event, but fixing $H_0$. We obtain a value of $m^2_g=2.08_{-4.25}^{+13.90} \cdot 10^{-44} \rm{eV^2/c^4}$ at 99.7\% confidence level (CL), when marginalising over the Hubble constant and GW friction term $\alpha_M$. We find poor constraints on $\alpha_M$, but demonstrate that for all the GW dispersions relations considered, including massive gravity, the GW must be emitted $\sim$ 1.74s before the Gamma-ray burst (GRB) and that the GW merger peak group velocity fractional discrepancy from $c$ is $\lesssim 10^{-17}$.

Replacements for Tue, 14 Apr 20

[64]  arXiv:1809.03504 (replaced) [pdf, other]

Title: Disentangling Coalescing Neutron Star-White Dwarf Binaries for LISA

Authors: Thomas M. Tauris

Comments: Published in PRL. This version includes corrected Eq.(7) published in Erratum

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

[65]  arXiv:1812.06976 (replaced) [pdf, other]

Title: The dark matter interpretation of the 3.5-keV line is inconsistent with blank-sky observations

Authors: Christopher Dessert, Nicholas L. Rodd, Benjamin R. Safdi

Comments: v1, 6+13 pages, 3 + 11 figures; v2, updated to version published in Science. Supplementary data at this https URL and supplementary analysis examples at this https URL

Journal-ref: Science 367, 1465 (2020)

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

[66]  arXiv:1904.07789 (replaced) [pdf, other]

Title: Constraining the masses of microlensing black holes and the mass gap with Gaia DR2

Authors: Łukasz Wyrzykowski, Ilya Mandel

Comments: 12 pages, published as Wyrzykowski&Mandel, 2020, A&A, 636, A20

Journal-ref: A&A 636, A20 (2020)

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

[67]  arXiv:1904.08427 (replaced) [pdf, ps, other]

Title: Towards an accurate description of an accretion induced collapse and the associated ejected mass

Authors: Amir Sharon, Doron Kushnir

Comments: Accepted for publication in ApJ

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

[68]  arXiv:1908.08913 (replaced) [pdf, other]

Title: A Galaxy-Targeted Search for the Optical Counterpart of the Candidate NS-BH Merger S190814bv with Magellan

Authors: S. Gomez, G. Hosseinzadeh, P. S. Cowperthwaite, V. A. Villar, E. Berger, T. Gardner, K. D. Alexander, R. Chornock, M. R. Drout, T. Eftekhari, W. Fong, K. Gill, R. Margutti, M. Nicholl, K. Paterson, P. K. G. Williams

Comments: 10 pages, 1 table, 4 figures, accepted to ApJL

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

[69]  arXiv:1909.09613 (replaced) [pdf, other]

Title: Time-step dependent force interpolation scheme for suppressing numerical Cherenkov instability in relativistic particle-in-cell simulations

Authors: Yingchao Lu, Patrick Kilian, Fan Guo, Hui Li, Edison Liang

Comments: 11 pages, single column, one figure

Subjects: Computational Physics (physics.comp-ph); High Energy Astrophysical Phenomena (astro-ph.HE); Accelerator Physics (physics.acc-ph); Plasma Physics (physics.plasm-ph)

[70]  arXiv:1910.14004 (replaced) [pdf, other]

Title: Characterization of the Nucleus, Morphology and Activity of Interstellar Comet 2I/Borisov by Optical and Near-Infrared GROWTH, Apache Point, IRTF, ZTF and Keck Observations

Authors: Bryce T. Bolin, Carey M. Lisse, Mansi M. Kasliwal, Robert Quimby, Hanjie Tan, Chris Copperwheat, Zhong-Yi Lin, Alessandro Morbidelli, Lyu Abe, Philippe Bendjoya, James Bauer, Kevin B. Burdge, Michael Coughlin, Christoffer Fremling, Ryosuke Itoh, Michael Koss, Frank J. Masci, Syota Maeno, Eric E. Mamajek, Federico Marocco, Katsuhiro Murata, Jean-Pierre Rivet, Michael L. Sitko, Daniel Stern, David Vernet, Richard Walters, Lin Yan, Igor Andreoni, Varun Bhalerao, Dennis Bodewits, Kishalay De, Kunal P. Deshmukh, Eric C. Bellm, Nadejda Blagorodnova, Derek Buzasi, S. Bradley Cenko, Chan-Kao Chang, Drew Chojnowski, Richard Dekany, Dmitry A. Duev, Matthew Graham, Mario Juric, Emily A. Kramer, Shrinivas R. Kulkarni, Thomas Kupfer, Ashish Mahabal, James D. Neill, Chow-Choong Ngeow, Bryan Penprase, Reed Riddle, et al. (5 additional authors not shown)

Comments: 21 pages, 7 figures, 1 table. First round of revisions

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

[71]  arXiv:1911.04359 (replaced) [pdf, other]

Title: Relativistic and non-Gaussianity contributions to the one-loop power spectrum

Authors: Rebeca Martinez-Carrillo, Josue De-Santiago, Juan Carlos Hidalgo, Karim A. Malik

Comments: Corrected typos, added references. Matches version accepted by JCAP

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

[72]  arXiv:1911.05751 (replaced) [pdf, other]

Title: Cosmology dependence of galaxy cluster scaling relations

Authors: Priyanka Singh, Alex Saro, Matteo Costanzi, Klaus Dolag

Comments: 15 pages, 8 figures, 8 tables. Accepted for publication in MNRAS

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

[73]  arXiv:1912.07587 (replaced) [pdf, other]

Title: Peccei-Quinn Phase Transition at LIGO

Authors: Benedict von Harling, Alex Pomarol, Oriol Pujolas, Fabrizio Rompineve

Comments: 27 pages, 7 figure. v2: references added

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

[74]  arXiv:2001.01563 (replaced) [pdf, other]

Title: Understanding galaxy formation and evolution through an all-sky submillimetre spectroscopic survey

Authors: Mattia Negrello, Matteo Bonato, Zhen-Yi Cai, Helmut Dannerbauer, Gianfranco De Zotti, Jacques Delabrouille, Douglas Scott

Comments: 17 pages, 7 figures, accepted for publication in PASA

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

[75]  arXiv:2001.02187 (replaced) [pdf, other]

Title: Explaining the chemical trajectories of accreted and in-situ halo stars of the Milky Way

Authors: Chris B. Brook, Daisuke Kawata, Brad K. Gibson, Carme Gallart

Comments: Accepted version MNRAS

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

[76]  arXiv:2001.10761 (replaced) [pdf, ps, other]

Title: Are persistent emission luminosity and rotation measure of fast radio bursts related?

Authors: Yuan-Pei Yang, Qiao-Chu Li, Bing Zhang

Comments: 6 pages, 1 figure, 1 table, accepted for publication in ApJ

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

[77]  arXiv:2002.04073 (replaced) [pdf, ps, other]

Title: Investigating Opacity Modifications and Reaction Rate Uncertainties to Resolve the Cepheid Mass Discrepancy

Authors: Joyce A. Guzik (1), Ebraheem Farag (2), Jakub Ostrowski (3), Nancy R. Evans (4), Hilding Neilson (5), Sofia Moschou (4), Jeremy J. Drake (4) ((1) Los Alamos National Laboratory, Los Alamos, NM, USA, (2) Arizona State U., Tempe, AZ, USA, (3) Pedagogical U. of Cracow, Krakow, Poland, (4) Harvard Smithsonian Center for Astrophysics, Cambridge, MA, USA, (5), U. Toronto, Toronto, ON, Canada)

Comments: Revised version, 6 pages, 3 figures, enlarged Figure 2 and revised captions, submitted for Astronomical Society of the Pacific Conference Series "RRLyrae/Cepheid2019: Frontiers of Classical Pulsators: Theory and Observations", Cloudcroft, NM, USA October 13-18, 2019

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

[78]  arXiv:2002.09955 (replaced) [pdf, other]

Title: Observational constraints on dark matter decaying via gravity portals

Authors: Sun Xu-Dong, Dai Ben-Zhong

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

[79]  arXiv:2002.10364 (replaced) [pdf, ps, other]

Title: Revisiting the 2PN pericentre precession in view of possible future measurements of it

Authors: Lorenzo Iorio

Comments: Latex2e, 25 pages, 2 figures, no tables. Accepted for publication in Universe

Journal-ref: Universe 2020, 6(4), 53

Subjects: General Relativity and Quantum Cosmology (gr-qc); Earth and Planetary Astrophysics (astro-ph.EP); Space Physics (physics.space-ph)

[80]  arXiv:2003.03903 (replaced) [pdf, other]

Title: Analytic solutions in Einstein-aether scalar field cosmology

Authors: Andronikos Paliathanasis, Genly Leon (Catolica del Norte U.)

Comments: 16 pages, 2 figures, to appear in EPJC

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

[81]  arXiv:2003.06248 (replaced) [pdf, other]

Title: High Quality Software for Planetary Science from Space

Authors: Francesco Lazzarotto, Gabriele Cremonese, Alice Lucchetti, Cristina Re, Emanuele Simioni, Maurizio Pajola, Pamela Cambianica, Giovanni Munaretto

Comments: presentation at XVI Congresso Nazionale di Scienze Planetarie (National Conference on Planetary Sciences) held at Centro Culturale San Gaetano, via Altinate, 71, Padova, Italy on 3-7 February, 2020 Affiliation: University of Padova, 6 pages, 4 figures

Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Software Engineering (cs.SE)

[82]  arXiv:2004.01393 (replaced) [pdf, other]

Title: Reconstruction of late-time cosmology using Principal Component Analysis

Authors: Ranbir Sharma, Ankan Mukherjee, H. K. Jassal

Comments: 21 pages, 8 figures, references added

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

[83]  arXiv:2004.03511 (replaced) [pdf, other]

Title: Towards An Integrated Optical Transient Utility

Authors: S. R. Kulkarni

Comments: Submitted to PASP

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

[84]  arXiv:2004.03562 (replaced) [pdf, other]

Title: Fermi Large Area Telescope Observations of the Fast-dimming Crab Nebula in 60-600 MeV

Authors: Paul K. H. Yeung, Dieter Horns

Comments: Re-submitted to A&A on 14.02.2020, revised in response to a referee report; Original version submitted on 19.09.2019

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

[85]  arXiv:2004.04702 (replaced) [pdf, other]

Title: Cosmology with the Wide-Field Infrared Survey Telescope -- Synergies with the Rubin Observatory Legacy Survey of Space and Time

Authors: Tim Eifler, Melanie Simet, Elisabeth Krause, Christopher Hirata, Hung-Jin Huang, Xiao Fang, Vivian Miranda, Rachel Mandelbaum, Cyrille Doux, Chen Heinrich, Eric Huff, Hironao Miyatake, Shoubaneh Hemmati, Jiachuan Xu, Paul Rogozenski, Peter Capak, Ami Choi, Olivier Dore, Bhuvnesh Jain, Mike Jarvis, Niall MacCrann, Dan Masters, Eduardo Rozo, David N. Spergel, Michael Troxel, Anja von der Linden, Yun Wang, David H. Weinberg, Lukas Wenzl, Hao-Yi Wu

Comments: added references, comments welcome

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

• New submissions
• Cross-lists
• Replacements