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New submissions for Thu, 27 Feb 20

[1]  arXiv:2002.11115 [pdf, other]

Title: The interior and atmosphere of the habitable-zone exoplanet K2-18b

Authors: Nikku Madhusudhan, Matthew C. Nixon, Luis Welbanks, Anjali A. A. Piette, Richard A. Booth

Comments: ApJ Letters, in press

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

Exoplanets orbiting M dwarfs present a valuable opportunity for their detection and atmospheric characterisation. This is evident from recent inferences of H$_2$O in such atmospheres, including that of the habitable-zone exoplanet K2-18b. With a bulk density between Earth and Neptune, K2-18b may be expected to possess a H/He envelope. However, the extent of such an envelope and the thermodynamic conditions of the interior remain unexplored. In the present work, we investigate the atmospheric and interior properties of K2-18b based on its bulk properties and its atmospheric transmission spectrum. We constrain the atmosphere to be H$_2$-rich with a H$_2$O volume mixing ratio of $0.02-14.8$%, consistent with previous studies, and find a depletion of CH$_4$ and NH$_3$, indicating chemical disequilibrium. We do not conclusively detect clouds/hazes in the observable atmosphere. We use the bulk parameters and retrieved atmospheric properties to constrain the internal structure and thermodynamic conditions in the planet. The constraints on the interior allow multiple scenarios between rocky worlds with massive H/He envelopes and water worlds with thin envelopes. We constrain the mass fraction of the H/He envelope to be $\lesssim 6$%; spanning $\lesssim 10^{-5}$ for a predominantly water world to $\sim6$% for a pure iron interior. The thermodynamic conditions at the surface of the H$_2$O layer range from the super-critical to liquid phases, with a range of solutions allowing for habitable conditions on K2-18b. Our results demonstrate that the potential for habitable conditions is not necessarily restricted to Earth-like rocky exoplanets.

[2]  arXiv:2002.11116 [pdf, ps, other]

Title: EUCLIA. II. On the puzzling large UV to X-ray lags in Seyfert galaxies

Authors: Zhen-Yi Cai (USTC), Jun-Xian Wang (USTC), Mouyuan Sun (XMU)

Comments: ApJ accepted

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

Recent intense X-ray and UV monitoring campaigns with Swift have detected clear UV lags behind X-ray in several local active galactic nuclei (AGNs). The UV to X-ray lags are often larger (by a factor up to ~ 20) than expected if the UV variation is simply due to the X-ray reprocessing. We previously developed a model in which the UV/optical variations are attributed to disk turbulences, and the effect of large-scale turbulence is considered. Our model, which overcomes many severe challenges to the reprocessing scheme, can well explain the observed variations in NGC 5548, particularly the correlations and lags among the UV/optical bands. In this work, assuming the corona heating is associated with turbulences in the inner accretion disk, we extend our study to model the correlations and lags between the X-ray and UV/optical bands. We find that our model, without the need of light echoing, can well reproduce the observed UV to X-ray lags and the optical to UV lags simultaneously in four local Seyfert galaxies, including NGC 4151, NGC 4395, NGC 4593, and NGC 5548. In our scenario, relatively larger UV to X-ray lag is expected for AGN with smaller innermost disk radius and thus more compact corona. Interestingly, for these Seyfert galaxies studied in this work, sources with relatively larger UV to X-ray lags do have broader Fe Ka lines, indicative of relativistic broadening due to more compact corona and smaller innermost disk radius. If confirmed with more X-ray and UV monitoring campaigns, this interesting discovery would provide a new probe to the inner disk/corona.

[3]  arXiv:2002.11117 [pdf, other]

Title: Elevated ionizing photon production efficiency in faint high-equivalent-width Lyman-alpha emitters

Authors: Michael V. Maseda, Roland Bacon, Daniel Lam, Jorryt Matthee, Jarle Brinchmann, Joop Schaye, Ivo Labbe, Kasper B. Schmidt, Leindert Boogaard, Rychard Bouwens, Sebastiano Cantalupo, Marijn Franx, Takuya Hashimoto, Hanae Inami, Haruka Kusakabe, Guillaume Mahler, Themiya Nanayakkara, Johan Richard, Lutz Wisotzki

Comments: 12 Pages, 6 Figures; Accepted for publication in MNRAS

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

While low-luminosity galaxies dominate number counts at all redshifts, their contribution to cosmic Reionization is poorly understood due to a lack of knowledge of their physical properties. We isolate a sample of 35 z~4-5 continuum-faint Lyman-alpha emitters from deep VLT/MUSE spectroscopy and directly measure their Halpha emission using stacked Spitzer/IRAC Ch. 1 photometry. Based on Hubble Space Telescope imaging, we determine that the average UV continuum magnitude is fainter than -16 (~0.01 L_star), implying a median Lyman-alpha equivalent width of 249 Angstroms. By combining the Halpha measurement with the UV magnitude we determine the ionizing photon production efficiency, xi_ion, a first for such faint galaxies. The measurement of log (xi_ion [Hz/erg]) = 26.28 (+0.28; -0.40) is in excess of literature measurements of both continuum- and emission line-selected samples, implying a more efficient production of ionizing photons in these lower-luminosity, Lyman-alpha-selected systems. We conclude that this elevated efficiency can be explained by stellar populations with metallicities between 4e-4 and 0.008, with light-weighted ages less than 3 Myr.

[4]  arXiv:2002.11118 [pdf, other]

Title: Physics of Tidal Dissipation in Early-Type Stars and White Dwarfs: Hydrodynamical Simulations of Internal Gravity Wave Breaking in Stellar Envelopes

Authors: Yubo Su, Daniel Lecoanet, Dong Lai

Comments: 13 pages, 10 figures, submitted to MNRAS. Simulation video available at this http URL

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

In binaries composed of early-type stars and white dwarfs, the dominant tidal process involves the excitation of internal gravity waves (IGWs), which propagate towards the stellar surface, and their dissipation via nonlinear wave breaking. We perform 2D hydrodynamical simulations of this wave breaking process in a stratified, isothermal atmosphere. We find that, after an initial transient phase, the dissipation of the IGWs naturally generates a sharp critical layer, separating the lower stationary region (with no mean flow) and the upper "synchronized" region (with the mean flow velocity equal to the horizontal wave phase speed). While the critical layer is steepened by absorption of these waves, it is simultaneously broadened by Kelvin-Helmholtz instabilities such that, in steady state, the critical layer width is determined by the Richardson criterion. We study the absorption and reflection of incident waves off the critical layer and provide analytical formulae describing its long-term evolution. The result of this study is important for characterizing the evolution of tidally heated white dwarfs and other binary stars.

[5]  arXiv:2002.11119 [pdf, other]

Title: The Distinct Stellar-to-Halo Mass Relations of Satellite and Central Galaxies: Insights from the IllustrisTNG Simulations

Authors: Christoph Engler, Annalisa Pillepich, Gandhali D. Joshi, Dylan Nelson, Anna Pasquali, Eva K. Grebel, Thorsten Lisker, Elad Zinger, Martina Donnari, Federico Marinacci, Mark Vogelsberger, Lars Hernquist

Comments: Submitted to MNRAS. Key figures: 1 & 8. Comments welcome

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

We study the stellar-to-halo mass relation (SHMR) for central and satellite galaxies with total dynamical masses above 10^10.5 Msun using the suite of cosmological magneto-hydrodynamical simulations IllustrisTNG. In particular, we quantify environmental effects on satellite populations from TNG50, TNG100, and TNG300 located within the virial radius of group- and cluster-like hosts with total masses of 10^12-15.2 Msun. At fixed stellar mass, the satellite SHMR exhibits a distinct shift towards lower dynamical mass compared to the SHMR of centrals. Conversely, at fixed dynamical mass, satellite galaxies appear to have larger stellar-to-total mass fractions than centrals by up to a factor of a few. The systematic deviation from the central SHMR is larger for satellites in more massive hosts, at smaller cluster-centric distances, with earlier infall times, and that inhabit higher local density environments; moreover, it is in place already at early times (z < 2). Systematic environmental effects contribute to the perceived galaxy-to-galaxy variation in the measured SHMR when galaxies cannot be separated into satellites and centrals. The SHMR of satellites exhibits a larger scatter than centrals, over the whole range of dynamical mass (up to 0.8 dex). The shift of the satellite SHMR results mostly from tidal stripping of their dark matter, which affects satellites in an outside-in fashion: the departure of the satellite SHMR from the centrals' relation diminishes for measurements of dynamical mass in progressively smaller apertures. Finally, we provide a family of fitting functions for the SHMR predicted by IllustrisTNG.

[6]  arXiv:2002.11121 [pdf, other]

Title: A panoramic landscape of the Sagittarius stream in Gaia DR2 revealed with the STREAMFINDER spyglass

Authors: Rodrigo Ibata, Michele Bellazzini, Guillaume Thomas, Khyati Malhan, Nicolas Martin, Benoit Famaey, Arnaud Siebert

Comments: 11 pages, 4 figures, accepted for publication in ApJ Letters

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

We present the first full six-dimensional panoramic portrait of the Sagittarius stream, obtained by searching for wide stellar streams in the Gaia DR2 dataset with the STREAMFINDER algorithm. We use the kinematic behavior of the sample to devise a selection of Gaia RR Lyrae, providing excellent distance measurements along the stream. The proper motion data are complemented with radial velocities from public surveys. We find that the global morphological and kinematic properties of the Sagittarius stream are still reasonably well reproduced by the simple Law & Majewski (2010) model (LM10), although the model overestimates the leading arm and trailing arm distances by up to $\sim 15$%. The sample newly reveals the leading arm of the Sagittarius stream as it passes into very crowded regions of the Galactic disk towards the Galactic Anticenter direction. Fortuitously, this part of the stream is almost exactly at the diametrically opposite location from the Galactic Center to the progenitor, which should allow an assessment of the influence of dynamical friction and self-gravity in a way that is nearly independent of the underlying Galactic potential model.

[7]  arXiv:2002.11122 [pdf, other]

Title: The effect of the environment-dependent IMF on the formation and metallicities of stars over the cosmic history

Authors: Martyna Chruslinska, Tereza Jerabkova, Gijs Nelemans, Zhiqiang Yan

Comments: accepted for publication in A&A, main text: 10 pages, 8 figures, appendix: 5 pages, 6 figures, for associated data see this https URL

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

Recent observational and theoretical studies indicate that the stellar initial mass function (IMF) varies systematically with the environment (star formation rate - SFR, metallicity). Although the exact dependence of the IMF on those properties is likely to change with improving observational constraints, the reported trend in the shape of the IMF appears robust. We present the first study aiming to evaluate the effect of the IMF variations on the measured cosmic SFR density (SFRD) as a function of metallicity and redshift, $f_{\rm SFR}$(Z,z). We also study the expected number and metallicity of white dwarf, neutron star and black hole progenitors under different IMF assumptions. Applying the empirically driven IMF variations described by the integrated galactic IMF (IGIMF) theory, we correct $f_{\rm SFR}$(Z,z) obtained by Chruslinska & Nelemans (2019) and find lower SFRD at high redshifts as well as a higher fraction of metal-poor stars being formed. In the local Universe, our calculation applying the IGIMF theory suggests more white dwarf and neutron star progenitors in comparison with the universal IMF scenario, while the number of black hole progenitors remains unaffected.

[8]  arXiv:2002.11123 [pdf, ps, other]

Title: Diffusive shock acceleration in $N$ dimensions

Authors: Assaf Lavi, Ofir Arad, Yotam Nagar, Uri Keshet

Comments: 14 pages, 7 figures, comments welcome

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

Collisionless shocks are often studied in two spatial dimensions (2D), to gain insights into the 3D case. We analyze diffusive shock acceleration for an arbitrary number $N\in\mathbb{N}$ of dimensions. For a non-relativistic shock of compression ratio $\mathcal{R}$, the spectral index of the accelerated particles is $s_E=1+N/(\mathcal{R}-1)$; this curiously yields, for any $N$, the familiar $s_E=2$ (i.e., equal energy per logarithmic particle energy bin) for a strong shock in a mono-atomic gas. A precise relation between $s_E$ and the anisotropy along an arbitrary relativistic shock is derived, and is used to obtain an analytic expression for $s_E$ in the case of isotropic angular diffusion, affirming an analogous result in 3D. In particular, this approach yields $s_E = (1+\sqrt{13})/2 \simeq 2.30$ in the ultra-relativistic shock limit for $N=2$, and $s_E(N\to\infty)=2$ for any strong shock. The angular eigenfunctions of the isotropic-diffusion transport equation reduce in 2D to elliptic cosine functions, providing a rigorous solution to the problem; the first function upstream already yields a remarkably accurate approximation. We show how these and additional results can be used to promote the study of shocks in 3D.

[9]  arXiv:2002.11124 [pdf, other]

Title: Dark Energy Survey Year 1 Results: Cosmological Constraints from Cluster Abundances and Weak Lensing

Authors: DES Collaboration: Tim Abbott, Michel Aguena, Alex Alarcon, Sahar Allam, Steve Allen, James Annis, Santiago Avila, David Bacon, Alberto Bermeo, Gary Bernstein, Emmanuel Bertin, Sunayana Bhargava, Sebastian Bocquet, David Brooks, Dillon Brout, Elizabeth Buckley-Geer, David Burke, Aurelio Carnero Rosell, Matias Carrasco Kind, Jorge Carretero, Francisco Javier Castander, Ross Cawthon, Chihway Chang, Xinyi Chen, Ami Choi, Matteo Costanzi, Martin Crocce, Luiz da Costa, Tamara Davis, Juan De Vicente, Joseph DeRose, Shantanu Desai, H. Thomas Diehl, Jörg Dietrich, Scott Dodelson, Peter Doel, Alex Drlica-Wagner, Kathleen Eckert, Tim Eifler, Jack Elvin-Poole, Juan Estrada, Spencer Everett, August Evrard, Arya Farahi, Ismael Ferrero, Brenna Flaugher, Pablo Fosalba, Josh Frieman, Juan Garcia-Bellido, et al. (82 additional authors not shown)

Comments: 35 pages, 20 figures, submitted to Physical Review D

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

We perform a joint analysis of the counts and weak lensing signal of redMaPPer clusters selected from the Dark Energy Survey (DES) Year 1 dataset. Our analysis uses the same shear and source photometric redshifts estimates as were used in the DES combined probes analysis. Our analysis results in surprisingly low values for $S_8 =\sigma_8(\Omega_{\rm m}/0.3)^{0.5}= 0.65\pm 0.04$, driven by a low matter density parameter, $\Omega_{\rm m}=0.179^{+0.031}_{-0.038}$, with $\sigma_8-\Omega_{\rm m}$ posteriors in $2.4\sigma$ tension with the DES Y1 3x2pt results, and in $5.6\sigma$ with the Planck CMB analysis. These results include the impact of post-unblinding changes to the analysis, which did not improve the level of consistency with other data sets compared to the results obtained at the unblinding. The fact that multiple cosmological probes (supernovae, baryon acoustic oscillations, cosmic shear, galaxy clustering and CMB anisotropies), and other galaxy cluster analyses all favor significantly higher matter densities suggests the presence of systematic errors in the data or an incomplete modeling of the relevant physics. Cross checks with X-ray and microwave data, as well as independent constraints on the observable--mass relation from SZ selected clusters, suggest that the discrepancy resides in our modeling of the weak lensing signal rather than the cluster abundance. Repeating our analysis using a higher richness threshold ($\lambda \ge 30$) significantly reduces the tension with other probes, and points to one or more richness-dependent effects not captured by our model.

[10]  arXiv:2002.11126 [pdf, other]

Title: The Satellite Luminosity Function of M101 into the Ultra-Faint Dwarf Galaxy Regime

Authors: P. Bennet, D. J. Sand, D. Crnojevic, K. Spekkens, A. Karunakaran, D. Zaritsky, B. Mutlu-Pakdil

Comments: 9 Pages, 3 Figures, 1 Table, Submitted to ApJL

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

We have obtained deep Hubble Space Telescope (HST) imaging of four faint and ultra-faint dwarf galaxy candidates in the vicinity of M101 - Dw21, Dw22, Dw23 and Dw35, originally discovered by Bennet et al. (2017). Previous distance estimates using the surface brightness fluctuation technique have suggested that these four dwarf candidates are the only remaining viable M101 satellites identified in ground based imaging out to the virial radius of M101 (D~250 kpc). Advanced Camera for Surveys imaging of all four dwarf candidates shows no associated resolved stellar populations, indicating that they are thus background galaxies. We confirm this by generating simulated HST color magnitude diagrams of similar brightness dwarfs at the distance of M101. Our targets would have displayed clear, resolved red giant branches with dozens of stars if they had been associated with M101. With this information, we construct a satellite luminosity function for M101, which is 90% complete to M_V=-7.7 mag and 50% complete to M_V=-7.4 mag, that extends into the ultra-faint dwarf galaxy regime. The M101 system is remarkably poor in satellites in comparison to the Milky Way and M31, with only eight satellites down to an absolute magnitude of M_V=-7.7 mag, compared to the 14 and 26 seen in the Milky Way and M31, respectively. Further observations of Milky Way analogs are needed to understand the halo-to-halo scatter in their faint satellite systems, and connect them with expectations from cosmological simulations.

[11]  arXiv:2002.11129 [pdf, other]

Title: Local Group star formation in warm and self-interacting dark matter cosmologies

Authors: Mark R. Lovell (1,2), Wojciech Hellwing (3), Aaron Ludlow (4), Jesús Zavala (1), Andrew Robertson (2), Azadeh Fattahi (2), Carlos S. Frenk (2), Jennifer Hardwick (4) ((1) University of Iceland, (2) ICC Durham, (3) Warsaw, (4) ICRAR/UWA)

Comments: 17 pages, 13 figures. To be submitted to MNRAS. Contact: lovell@hi.is

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

The nature of the dark matter can affect the collapse time of dark matter haloes, and can therefore be imprinted in observables such as the stellar population ages and star formation histories of dwarf galaxies. In this paper we use high resolution hydrodynamical simulations of Local Group-analogue (LG) volumes in cold dark matter (CDM), sterile neutrino warm dark matter (WDM) and self-interacting dark matter (SIDM) models with the EAGLE galaxy formation code to study how galaxy formation times change with dark matter model. We are able to identify the same haloes in different simulations, since they share the same initial density field phases. We show that the stellar mass varies systematically with resolution by over a factor of two, in a manner that depends on the final stellar mass. The evolution of the stellar populations in SIDM is largely identical to that of CDM, but in WDM early star formation is instead suppressed. The time at which LG haloes can begin to form stars through atomic cooling is delayed by $\sim$200~Myr in WDM models compared to CDM. 70~per~cent of WDM haloes of mass $>10^{8}M_{\odot}$ collapse early enough to form stars before $z=6$, compared to 90~per~cent of CDM and SIDM galaxies. It will be necessary to measure stellar ages of old populations to a precision of better than 100~Myr, and to address degeneracies with the redshift of reionization, in order to use these observables to distinguish between dark matter models.

[12]  arXiv:2002.11130 [pdf, other]

Title: Magneto-gravity wave packet dynamics in strongly magnetised cores of evolved stars

Authors: Shyeh Tjing Loi

Comments: 18 pages, 14 figures, accepted for publication in MNRAS

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

Magnetic fields are believed to be generated in the cores of massive main sequence stars, and these may survive on to later stages of evolution. Observations of depressed dipole modes in red giant stars have been touted as evidence for these fields, but the predictions of existing magnetic theories have difficulty accommodating several aspects, including the need to return a fraction of wave energy from the core to the envelope, and the persistent gravity-like character of affected modes. In this work we perform a Hamiltonian ray tracing study investigating the dynamics of magneto-gravity waves in full spherical geometry, using realistic stellar models and magnetic field configurations. This technique applies in the limit where wavelengths are much shorter than scales of background variation. We conduct a comprehensive exploration of parameter space, examining the roles of wave frequency, spherical harmonic degree, wavevector polarisation, incoming latitude, field strength, field radius, and evolutionary state. We demonstrate that even in the presence of a strong field, there exist trajectories where waves remain predominantly gravity-like in character, and these are able to undergo reflection out of the core much like pure gravity waves. The remaining trajectories are ones where waves acquire significant Alfven character, becoming trapped and eventually dissipated. Orientation effects, i.e. wavevector polarisation and incoming latitude, are found to be crucial factors in determining the outcome (trapped versus reflected) of individual wave packets. The allowance for partial energy return from the core offers a solution to the conundrum faced by the magnetic hypothesis.

[13]  arXiv:2002.11131 [pdf, other]

Title: Obliquity Constraints on an Extrasolar Planetary-Mass Companion

Authors: Marta L. Bryan, Eugene Chiang, Brendan P. Bowler, Caroline V. Morley, Sarah Millholland, Sarah Blunt, Katelyn B. Ashok, Eric Nielsen, Henry Ngo, Dimitri Mawet, Heather A. Knutson

Comments: accepted to AJ

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

We place the first constraints on the obliquity of a planetary-mass companion (PMC) outside of the Solar System. Our target is the directly imaged system 2MASS J01225093-2439505 (2M0122), which consists of a 120 Myr 0.4 M_sun star hosting a 12-27 M_J companion at 50 AU. We constrain all three of the system's angular momentum vectors: how the companion spin axis, the stellar spin axis, and the orbit normal are inclined relative to our line of sight. To accomplish this, we measure projected rotation rates (vsini) for both the star and the companion using new near-infrared high-resolution spectra with NIRSPEC at Keck Observatory. We combine these with a new stellar photometric rotation period from TESS and a published companion rotation period from HST to obtain spin axis inclinations for both objects. We also fitted multiple epochs of astrometry, including a new observation with NIRC2/Keck, to measure 2M0122b's orbital inclination. The three line-of-sight inclinations place limits on the true de-projected companion obliquity and stellar obliquity. We find that while the stellar obliquity marginally prefers alignment, the companion obliquity tentatively favors misalignment. We evaluate possible origin scenarios. While collisions, secular spin-orbit resonances, and Kozai-Lidov oscillations are unlikely, formation by gravitational instability in a gravito-turbulent disk - the scenario favored for brown dwarf companions to stars - appears promising.

[14]  arXiv:2002.11134 [pdf, other]

Title: White dwarf deflagrations for Type Iax supernovae: polarization signatures from the explosion and from the companion interaction

Authors: M. Bulla, Z.-W. Liu, F. K. Röpke, S. A. Sim, M. Fink, M. Kromer, R. Pakmor, I. R. Seitenzahl

Comments: 7 pages, 3 figures; accepted for publication in A&A

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

Growing evidence suggests that Type Iax supernovae might be the result of thermonuclear deflagrations of Chandrasekhar-mass white dwarfs in binary systems. Here, we carry out Monte Carlo radiative transfer simulations and predict spectropolarimetric features originating from the supernova explosion and from the subsequent ejecta interaction with the companion star. Specifically, we calculate viewing-angle dependent flux and polarization spectra for a 3D model simulating the deflagration of a Chandrasekhar-mass white dwarf and for a second model simulating the ejecta interaction with a main-sequence star. We find that the intrinsic signal is weakly polarized and only mildly viewing-angle dependent, owing to the overall spherical symmetry of the explosion and the depolarizing contribution of iron-group elements dominating the ejecta composition. The interaction with the companion star carves out a cavity in the ejecta and produces a detectable but modest signal that is significant only at relatively blue wavelengths ($\lesssim$ 5000 $\unicode{x212B}$). In particular, increasingly fainter and redder spectra are predicted for observer orientations further from the cavity, while a modest polarization signal $P\sim0.2$ per cent is found at blue wavelengths for orientations 30$^\circ$ and 45$^\circ$ away from the cavity. We find a reasonable agreement between the interaction model viewed from these orientations and spectropolarimetric data of SN 2005hk and interpret the maximum-light polarization signal seen at blue wavelengths for this event as a possible signature of the ejecta-companion interaction. We encourage further polarimetric observations of SNe Iax to test whether our results can be extended and generalised to the whole SN Iax class.

[15]  arXiv:2002.11135 [pdf, other]

Title: Fingerprints of giant planets in the composition of solar twins

Authors: Richard A. Booth, James E. Owen

Comments: 11 pages, 5 figures. Accepted for publication in MNRAS

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

The Sun shows a $\sim 10$% depletion in refractory elements relative to nearby solar twins. It has been suggested that this depletion is a signpost of planet formation. The exoplanet statistics are now good enough to show that the origin of this depletion does not arise from the sequestration of refractory material inside the planets themselves. This conclusion arises because most sun-like stars host close-in planetary systems that are on average more massive than the Sun's. Using evolutionary models for the protoplanetary discs that surrounded the young Sun and solar twins we demonstrate that the origin of the depletion likely arises due to the trapping of dust exterior to the orbit of a forming giant planet. In this scenario a forming giant planet opens a gap in the gas disc, creating a pressure trap. If the planet forms early enough, while the disc is still massive, the planet can trap $\gtrsim 100 $M$_\oplus$ of dust exterior to its orbit, preventing the dust from accreting onto the star in contrast to the gas. Forming giant planets can create refractory depletions of $\sim 5-15$%, with the larger values occurring for initial conditions that favour giant planet formation (e.g. more massive discs, that live longer). The incidence of solar-twins that show refractory depletion matches both the occurrence of giant planets discovered in exoplanet surveys and "transition" discs that show similar depletion patterns in the material that is accreting onto the star.

[16]  arXiv:2002.11138 [pdf, other]

Title: Revealing the tidal scars of the Small Magellanic Cloud

Authors: Michele De Leo, Ricardo Carrera, Noelia E. D. Noel, Justin I. Read, Denis Erkal, Carme Gallart

Comments: Revised version submitted to MNRAS after referee report, 18 pages, 18 figures

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

Due to their close proximity, the Large and Small Magellanic Clouds (SMC/LMC) provide natural laboratories for understanding how galaxies form and evolve. With the goal of determining the structure and dynamical state of the SMC, we present new spectroscopic data for $\sim$ 3000 SMC red giant branch stars observed using the AAOmega spectrograph at the Anglo-Australian Telescope. We complement our data with further spectroscopic measurements from previous studies that used the same instrumental configuration and proper motions from the \textit{Gaia} Data Release 2 catalogue. Analysing the photometric and stellar kinematic data, we find that the SMC centre of mass presents a conspicuous offset from the velocity centre of its associated $\mbox{H\,{\sc i}}$ gas, suggesting that the SMC gas is likely to be far from dynamical equilibrium. Furthermore, we find evidence that the SMC is currently undergoing tidal disruption by the LMC within 2\,kpc of the centre of the SMC, and possibly all the way in to the very core. This is evidenced by a net outward motion of stars from the SMC centre along the direction towards the LMC and apparent tangential anisotropy at all radii. The latter is expected if the SMC is undergoing significiant tidal stripping, as we demonstrate using a suite of $N$-body simulations of the SMC/LMC system disrupting around the Milky Way. These results suggest that dynamical models for the SMC that assume a steady state will need to be revisited.

[17]  arXiv:2002.11139 [pdf, other]

Title: Optical Spectroscopy of nearby type1-LINERs

Authors: S. Cazzoli, I. Márquez, J. Masegosa, A. del Olmo, M. Povic, O. González-Martín, B. Balmaverde, L. Hernández-García, S. García-Burillo

Comments: Proceedings of the IAU Symposium 356, 'Nuclear activity in galaxies across cosmic time'. Based on Cazzoli et al. 2018, MNRAS, 480, 1106 available at this https URL

Journal-ref: Proceedings of the International Astronomical Union (356), 2019. Eds. M. Povic, J. Masegosa, H. Netzer, P. Marziani, P. Shastri, S. B. Tessema & S. H. Negu

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

We present the highlights from our recent study of 22 local (z$<$0.025) type-1 LINERs from the Palomar Survey, on the basis of optical long-slit spectroscopic observations taken with TWIN/CAHA, ALFOSC/NOT and HST/STIS (Cazzoli et al. 2018). Our goals were threefold: (a) explore the AGN- nature of these LINERs by studying the broad (BLR-originated) H$\alpha$ component; (b) derive a reliable interpretation for the multiple narrow components of emission lines by studying their kinematics and ionisation mechanism (via standard BPTs); (c) probe the neutral gas in the nuclei of these LINERs for the first time. Hence, kinematics and fluxes of a set of emission lines, from H$\beta$ to [SII], and the NaD doublet in absorption have been modelled and measured, after the subtraction of the underlying light from the stellar component.

[18]  arXiv:2002.11140 [pdf, other]

Title: Dynamical evolution of fractal structures in star-forming regions

Authors: Emma C. Daffern-Powell (1), Richard J. Parker (1) ((1) University of Sheffield, UK)

Comments: 12 pages, 10 figures, acccepted for publication in MNRAS

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

The Q-parameter is used extensively to quantify the spatial distributions of stars and gas in star-forming regions as well as older clusters and associations. It quantifies the amount of structure using the ratio of the average length of a minimum spanning tree, mbar, to the average length within the complete graph, sbar. The interpretation of the Q-parameter often relies on comparing observed values of Q, mbar and sbar to idealised synthetic geometries, where there is little or no match between the observed star-forming regions and the synthetic regions. We measure Q, mbar, and sbar over 10 Myr in N-body simulations which are compared to IC 348, NGC 1333, and the ONC. For each star-forming region we set up simulations that approximate their initial conditions for a combination of different virial rations and fractal dimensions. We find that dynamical evolution of idealised fractal geometries can account for the observed Q, mbar, and sbar values in nearby star-forming regions. In general, an initially fractal star-forming region will tend to evolve to become more smooth and centrally concentrated. However, we show that initial conditions, as well as where the edge of the region is defined, can cause significant differences in the path that a star-forming region takes across the mbar-sbar plot as it evolves. We caution that the observed Q-parameter should not be directly compared to idealised geometries. Instead, it should be used to determine the degree to which a star-forming region is either spatially substructured or smooth and centrally concentrated.

[19]  arXiv:2002.11142 [pdf, other]

Title: Full 5D characterisation of the Sagittarius stream with Gaia DR2 RR Lyrae

Authors: P. Ramos, C. Mateu, T. Antoja, A. Helmi, A. Castro-Ginard, E. Balbinot

Comments: 17 pages. Submitted to Astronomy and Astrophysics on 25th of February, 2020. Related on-line material available at this https URL

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

The Sagittarius stream is one of the best tools that we currently have to estimate the mass and shape of our Galaxy. However, assigning membership and obtaining the phase-space distribution of the stars that form the tails is quite challenging. Our goal is to produce a catalogue of RR Lyrae stars of Sagittarius and obtain an empiric measurement of the trends along the stream in sky position, distance and tangential velocities. We generate two initial samples from the Gaia DR2 RR Lyrae catalogue: one, selecting only the stars within \pm20deg of the orbital plane of Sagittarius (Strip) and the other, the result of applying the Pole Count Map (nGC3) algorithm. We then use the model-independent, deterministic method developed in this work to remove most of the contamination by detecting and isolating the stream in distance and proper motions. The output is two empiric catalogues: the Strip sample (higher-completeness, lower-purity) which contains 11 677 stars, and the nGC3 sample (higher-purity, lower-completeness) with 6 608 stars. We characterise the changes along the stream in all the available dimensions, the 5 astrometric ones plus the metallicity, covering more than 2pi rad in the sky and obtain new estimates for the apocentres and the mean [Fe/H] of the RR Lyrae population. Also, we show the first map of the two components of the tangential velocity, thanks to the combination of distances and proper motions. Finally, we detect the bifurcation in the leading arm and report no significant difference between the two branches, either in metallicity, kinematics or distance. We provide the largest sample of RR Lyrae candidates of Sagittarius, which can be used as an input for a spectroscopic follow-up or as a reference for the new generation of models of the stream through the interpolators in distance and velocity that we have constructed.

[20]  arXiv:2002.11161 [pdf, other]

Title: Low mass planet migration in three dimensional wind-driven inviscid discs: A negative corotation torque

Authors: Colin P. McNally, Richard P. Nelson, Sijme-Jan Paardekooper, Pablo Benitez-Llambay, Oliver Gressel

Comments: 18 pages, 19 figures, MNRAS accepted

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

We present simulations of low mass planet-disc interactions in inviscid three dimensional discs. We show that a wind-driven laminar accretion flow through the surface layers of the disc does not significantly modify the migration torque experienced by embedded planets. More importantly, we find that 3D effects lead to a dramatic change in the behaviour of the dynamical corotation torque compared to earlier 2D theory and simulations. Whereas it was previously shown that the dynamical corotation torque could act to slow and essentially stall the inward migration of a low mass planet, our results in 3D show that the dynamical corotation torque has the complete opposite effect and speeds up inward migration. Our numerical experiments implicate buoyancy resonances as the cause. These have two effects: (i) they exert a direct torque on the planet, whose magnitude relative to the Lindblad torque is measured in our simulations to be small; (ii) they torque the gas librating on horseshoe orbits in the corotation region and drive evolution of its vortensity, leading to the negative dynamical corotation torque. This indicates that at low turbulent viscosity, the detailed vertical thermal structure of the protoplanetary disc plays an important role in determining the migration behaviour of embedded planets. If this result holds up under more a refined treatment of disc thermal evolution, then it has important implications for understanding the formation and early evolution of planetary systems.

[21]  arXiv:2002.11178 [pdf, other]

Title: Limits on Absorption from a 332-MHz survey for Fast Radio Bursts

Authors: K. M. Rajwade, M. B. Mickaliger, B. W. Stappers, C. G. Bassa, R. P. Breton, A. Karastergiou, E. F. Keane

Comments: 12 pages, 9 Figures, 2 Tables, Second revision submitted to MNRAS

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

Fast Radio Bursts (FRBs) are bright, extragalactic radio pulses whose origins are still unknown. Until recently, most FRBs have been detected at frequencies greater than 1 GHz with a few exceptions at 800 MHz. The recent discoveries of FRBs at 400 MHz from the Canadian Hydrogen Intensity Mapping Experiment (CHIME) telescope has opened up possibilities for new insights about the progenitors while many other low frequency surveys in the past have failed to find any FRBs. Here, we present results from a FRB survey recently conducted at the Jodrell Bank Observatory at 332 MHz with the 76-m Lovell telescope for a total of 58 days. We did not detect any FRBs in the survey and report a 90$\%$ upper limit of 5500 FRBs per day per sky for a Euclidean Universe above a fluence threshold of 46 Jy ms. We discuss the possibility of absorption as the main cause of non-detections in low frequency (< 800 MHz) searches and invoke different absorption models to explain the same. We find that Induced Compton Scattering alone cannot account for absorption of radio emission and that our simulations favour a combination of Induced Compton Scattering and Free-Free Absorption to explain the non-detections. For a free-free absorption scenario, our constraints on the electron density are consistent with those expected in the post-shock region of the ionized ejecta in Super-Luminous SuperNovae (SLSNe).

[22]  arXiv:2002.11206 [pdf, other]

Title: Non-intrusive hierarchical coupling strategies for multi-scale simulations in gravitational dynamics

Authors: Simon Portegies Zwart (Leiden Observatory), Inti Pelupessy (NLeSc), Carmen Martinez-Barbosa (Deltares), Arjen van Elteren (Leiden Observatory), Steve McMillan (Drexel University)

Comments: Accepted for publication in Communications in Nonlinear Science and Numerical Simulation (CNSNS) The associated software is part of the AMUSE framework and can be downloaded from http:www.amusecode.org

Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Chaotic Dynamics (nlin.CD)

Hierarchical code coupling strategies make it possible to combine the results of individual numerical solvers into a self-consistent symplectic solution. We explore the possibility of allowing such a coupling strategy to be non-intrusive. In that case, the underlying numerical implementation is not affected by the coupling itself, but its functionality is carried over in the interface. This method is efficient for solving the equations of motion for a self-gravitating system over a wide range of scales. We adopt a dedicated integrator for solving each particular part of the problem and combine the results to a self-consistent solution. In particular, we explore the possibilities of combining the evolution of one or more microscopic systems that are embedded in a macroscopic system. The here presented generalizations of Bridge include higher-order coupling strategies (from the classic 2nd order up to 10th-order), but we also demonstrate how multiple bridges can be nested and how additional processes can be introduced at the bridge time-step to enrich the physics, for example by incorporating dissipative processes. Such augmentation allows for including additional processes in a classic Newtonian N-body integrator without alterations to the underlying code. These additional processes include for example the Yarkovsky effect, dynamical friction or relativistic dynamics. Some of these processes operate on all particles whereas others apply only to a subset.
The presented method is non-intrusive in the sense that the underlying methods remain operational without changes to the code (apart from adding the get- and set-functions to enable the bridge operator). As a result, the fundamental integrators continue to operate with their internal time step and preserve their local optimizations and parallelism.
... abridged ...

[23]  arXiv:2002.11214 [pdf, other]

Title: An astrophysically motivated ranking criterion for low-latency electromagnetic follow-up of gravitational wave events

Authors: M. Celeste Artale, Yann Bouffanais, Michela Mapelli, Nicola Giacobbo, Nadeen B. Sabha, Filippo Santoliquido, Mario Pasquato, Mario Spera

Comments: 12 pages, 6 figures. Submitted to MNRAS

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

We investigate the properties of the host galaxies of compact binary mergers across cosmic time. To this end, we combine population synthesis simulations together with galaxy catalogues from the hydrodynamical cosmological simulation \eagle\ to derive the properties of the host galaxies of binary neutron stars (BNS), black hole-neutron star (BHNS) and binary black hole (BBH) mergers. Within this framework, we derive the host galaxy probability, i.e., the probability that a galaxy hosts a compact binary coalescence as a function of its stellar mass, star formation rate, $K_s$ magnitude and $B$ magnitude. This quantity is particularly important for low-latency searches of gravitational wave (GW) sources as it provides a way to rank galaxies lying inside the credible region in the sky of a given GW detection, hence reducing the number of viable host candidates. Furthermore, even if no electromagnetic counterpart is detected, one can still use the proposed ranking criterion to classify the galaxies contained in the error box. Our results show that massive galaxies (or equivalently galaxies with a high luminosity in $K_s$ band) have a higher probability of hosting BNS, BHNS, and BBH mergers. We provide the probabilities in a suitable format to be implemented in future low-latency searches.

[24]  arXiv:2002.11225 [pdf, other]

Title: A classification algorithm for time-domain novelties in preparation for LSST alerts: Application to variable stars and transients detected with DECam in the Galactic Bulge

Authors: Monika D. Soraisam, Abhijit Saha, Thomas Matheson, Chien-Hsiu Lee, Gautham Narayan, A. Katherina Vivas, Carlos Scheidegger, Niels Oppermann, Edward W. Olszewski, Sukriti Sinha, Sarah R. DeSantis

Comments: 20 pages + Appendix, accepted to ApJ

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

With the advent of the Large Synoptic Survey Telescope (LSST), time-domain astronomy will be faced with an unprecedented volume and rate of data. Real-time processing of variables and transients detected by such large-scale surveys is critical to identifying the more unusual events and allocating scarce follow-up resources efficiently. We develop an algorithm to identify these novel events within a given population of variable sources. We determine the distributions of magnitude changes (dm) over time intervals (dt) for a given passband f, pf(dm|dt), and use these distributions to compute the likelihood of a test source being consistent with the population, or an outlier. We demonstrate our algorithm by applying it to the DECam multi-band time-series data of more than 2000 variable stars identified by Saha et al. (2019) in the Galactic Bulge that are largely dominated by long-period variables and pulsating stars. Our algorithm discovers 18 outlier sources in the sample, including a microlensing event, a dwarf nova, and two chromospherically active RS CVn stars, as well as sources in the Blue Horizontal Branch region of the color-magnitude diagram without any known counterparts. We compare the performance of our algorithm for novelty detection with multivariate KDE and Isolation Forest on the simulated PLAsTiCC dataset. We find that our algorithm yields comparable results despite its simplicity. Our method provides an efficient way for flagging the most unusual events in a real-time alert-broker system.

[25]  arXiv:2002.11274 [pdf, ps, other]

Title: Structures, stellar population properties, AGN fractions, and environments of massive compact galaxies at $1 < z < 2$ in 3D--{\it HST}/CANDELS

Authors: Yizhou Gu, Guanwen Fang, Qirong Yuan, Shiying Lu

Comments: accepted for publication in PASP

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

We present a study on structures and physical properties of massive ($M_* >10^{10} M_{\sun} $) compact galaxies at $1.0<z<2.0$ in five 3D--{\it HST}/CANDELS fields. Compared with the extended star-forming galaxies (eSFGs), compact star-forming galaxies (cSFGs) are found to have the lower level of star formation, and mainly distribute in the quiescent region of the {\it UVJ} diagram. The distributions of dust attenuation and S{\'e}rsic index support that the progenitors of cQGs are cSFGs, and cSFGs are at a transitional phase between eSFGs and cQGs. The prevalence of X-ray selected AGNs ($\sim 28\%$) is confirmed in the cSFGs at $1<z<2$ which indicates that the violent gas-rich processes such as merger and disk instability could drive the structure to be more compact, and trigger both star formation and black hole growth in the central regions. Our results support the "two-step" scenario that the cSFGs at $1<z<2$ are the intermediate population after compaction but before a quick quenching. Our analysis of parametric and nonparametric morphologies shows that cQGs (eQGs) are more concentrated and have less substructures than cSFGs (eSFGs), and quenching and compactness should be associated with each other. The cSFGs at $1.5<z<2$ ($1<z<1.5$) prefer to be in higher (lower) density environment, similar as cQGs (eSFGs). It suggests that merger or strong interaction might be the main driving mechanism of compaction at higher redshifts, whereas the disk instability of individual galaxies might play a more important role on the formation of cSFGs at lower redshifts.

[26]  arXiv:2002.11278 [pdf, other]

Title: Merging Black Holes in the Low-mass and High-mass Gaps from 2+2 Quadruple Systems

Authors: Giacomo Fragione, Abraham Loeb, Frederic A. Rasio

Comments: 7 pages, 1 Table, 4 Figures

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

The origin of the black hole (BH) binary mergers observed by LIGO-Virgo is still highly uncertain, as are the boundaries of the stellar BH mass function. The most up-to-date stellar evolution models predict a dearth of BHs both at masses $\gtrsim 50$ M$_\odot$ and $\lesssim 5$ M$_\odot$, thus leaving low- and high-mass gaps in the BH mass function. A natural way to form BHs of these masses is through mergers of neutron stars (NSs; for the low-mass gap) or lower-mass BHs (for the high-mass gap); the low- or high-mass-gap BH produced as a merger product can then be detected by LIGO-Virgo if it merges again with a new companion. We show that the evolution of a 2+2 quadruple system (a wide binary system in which each component is itself a binary) can naturally lead to BH mergers with component masses in the low- or high-mass gaps. In our scenario, the BH in the mass gap originates from the merger of two NSs, or two BHs, in one of the two binaries and the merger product is imparted a recoil velocity, which triggers its interaction with the other binary component of the quadruple system. The outcome of this three-body interaction is usually a new eccentric compact binary containing the BH in the mass gap, which can then merge again. As the sensitivity of GW detectors improves, tighter constraints will soon be placed on the stellar BH mass function, thus shedding light on the low- and high-mass gaps and constraining formation channels for merging binaries like the one we explore here.

[27]  arXiv:2002.11348 [pdf, ps, other]

Title: Chiral Radiation Transport Theory of Neutrinos

Authors: Naoki Yamamoto, Di-Lun Yang

Comments: 21 pages, no figures

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

We construct the chiral radiation transport equation for left-handed neutrinos in the context of radiation hydrodynamics for core-collapse supernovae. Based on the chiral kinetic theory incorporating quantum corrections due to the chirality of fermions, we derive a general-relativistic form of the chiral transfer equation with collisions. We show that such quantum corrections explicitly break the spherical symmetry and axisymmetry of the system. In the inertial frame, in particular, we find that the so-called side jump leads to quantum corrections in the collisions between neutrinos and matter. We also derive analytic forms of such corrections in the emission and absorption rates for the neutrino absorption process. These corrections result in the generation of kinetic helicity and cross helicity of matter, which should then modify the subsequent evolution of matter. This theoretical framework can be applied to investigate the impacts of the chirality of neutrinos on the evolution of core-collapse supernovae.

[28]  arXiv:2002.11355 [pdf, other]

Title: New Constraints on the Supranuclear Equation of State and the Hubble Constant from Nuclear Physics -- Multi-Messenger Astronomy

Authors: Tim Dietrich, Michael W. Coughlin, Peter T. H. Pang, Mattia Bulla, Jack Heinzel, Lina Issa, Ingo Tews, Sarah Antier

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc); Nuclear Theory (nucl-th)

Neutron-star mergers are associated with violent phenomena that probe physical principles under extreme conditions that are not reproducible in any terrestrial laboratory. Thus, their multi-messenger analysis combining gravitational-wave and electromagnetic signatures from multiple wavelengths is not only of astrophysical interest, but it also allows studying the behavior of supranuclear dense matter, testing the fabric of spacetime, probing the principles of general relativity, and measuring the expansion rate of the Universe. In this work, we perform a multi-messenger analysis of the gravitational wave signal GW170817 and its electromagnetic counterparts AT2017gfo and GRB170817A. By incorporating information from the NICER observation of PSR J0030+0451, the radio observations of PSR J0740+6620, and nuclear theory computations using chiral effective field theory, we provide new constraints on the neutron-star equation of state and the Hubble constant. For our analysis, we make use of the new waveform approximant IMRPhenomPv2_NRTidalv2 for the interpretation of the gravitational wave signal, we employ a newly developed kilonova model, and we derive a new prediction for the debris disk mass surrounding the binary neutron star merger remnant. We determine the radius of a 1.4 solar mass neutron star to be $R_{1.4M_\odot}=10.98^{+0.37}_{-0.38} \rm km$ at $1\sigma$ uncertainty and $R_{1.4M_\odot}=10.98^{+1.00}_{-0.69} \rm km$ at $2\sigma$ uncertainty. In addition, we estimate the Hubble constant to be $H_0=68.4^{+5.2}_{-4.7}\ \rm km /Mpc/s$ at $1\sigma$ uncertainty. We test the consistency of our results and the robustness of our methods by also analyzing the second binary neutron-star merger detection GW190425 and the fact that no electromagnetic counterpart was observed for this event.

[29]  arXiv:2002.11357 [pdf, other]

Title: Asymptotic expansions for the Large Scale Structure

Authors: Shi-Fan Chen, Massimo Pietroni

Comments: 27 pages, 12 figures

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

We explore the deep ultraviolet (that is, short-distance) limit of the power spectrum (PS) and of the correlation function of a cold dark matter dominated Universe. While for large scales the PS can be written as a double series expansion, in powers of the linear PS and of the wavenumber $k$, we show that, in the opposite limit, it can be expressed via an expansion in powers of the form $1/k^{d+2n}$, where $d$ is the number of spatial dimensions, and $n$ is a non negative integer. The coefficients of the terms of the expansion are nonperturbative in the linear PS, and can be interpreted in terms of the probability density function for the displacement field, evaluated around specific configurations of the latter, that we identify. In the case of the Zel'dovich dynamics, these coefficients can be determined analytically, whereas for the exact dynamics they can be treated as fit, or nuisance, parameters. We confirm our findings with numerical simulations and discuss the necessary steps to match our results to those obtained for larger scales and to actual measurements.

[30]  arXiv:2002.11388 [pdf, other]

Title: Light curves of ten Centaurs from K2 measurements

Authors: G. Marton, Cs. Kiss, L. Molnár, A. Pál, A. Farkas-Takács, Gy. M. Szabó, T. Müller, V. Alí-Lagoa, R. Szabó, J. Vinkó, K. Sárneczky, Cs. E. Kalup, A. Marciniak, R. Duffard, L. L. Kiss

Comments: 17 pages, 7 figures, 3 tables

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

Here we present the results of visible range light curve observations of ten Centaurs using the Kepler Space Telescope in the framework of the K2 mission. Well defined periodic light curves are obtained in six cases allowing us to derive rotational periods, a notable increase in the number of Centaurs with known rotational properties. The low amplitude light curves of (471931) 2013 PH44 and (250112) 2002 KY14 can be explained either by albedo variegations, binarity or elongated shape. (353222) 2009 YD7 and (514312) 2016 AE193 could be rotating elongated objects, while 2017 CX33 and 2012 VU85 are the most promising binary candidates due to their slow rotations and higher light curve amplitudes. (463368) 2012 VU85 has the longest rotation period, P=56.2h observed among Centaurs. The P>20h rotation periods obtained for the two potential binaries underlines the importance of long, uninterrupted time series photometry of solar system targets that can suitably be performed only from spacecraft, like the Kepler in the K2 mission, and the currently running TESS mission.

[31]  arXiv:2002.11406 [pdf, other]

Title: Combined analysis of AMS-02 (Li,Be,B)/C, N/O, 3He, and 4He data

Authors: Nathanael Weinrich, Yoann Génolini, Mathieu Boudaud, Laurent Derome, David Maurin

Comments: 20 pages, 19 figures, 2 tables

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

The AMS-02 experiment measured several secondary-to-primary ratios enabling a detailed study of Galactic cosmic-ray transport. We constrain previously derived benchmark scenarios (based on AMS-02 B/C data only) using other secondary-to-primary ratios, to test the universality of transport and the presence of a low-rigidity diffusion break. We use the 1D thin disc/thick halo propagation model of USINE and a $\chi^2$ minimisation accounting for a covariance matrix of errors (AMS-02 systematics) and nuisance parameters (cross-sections and solar modulation uncertainties). The combined analysis of AMS-02 Li/C, Be/C, and B/C strengthens the case for a diffusion slope of $\delta=0.50\pm 0.03$ with a low-rigidity break or upturn of the diffusion coefficient at GV rigidities. Our simple model can successfully reproduce all considered data (Li/C, Be/C, B/C, N/O, and 3He/4He), although several issues remain: (i) the quantitative agreement depends on the assumptions made on the not well constrained correlation lengths of AMS-02 data systematics; (ii) combined analyses are very sensitive to production cross sections, and we find post-fit values differing by $\sim5-15\%$ from their most likely values (roughly within currently estimated nuclear uncertainties); (iii) two very distinct regions of the parameter space remain viable, either with reacceleration and convection, or with purely diffusive transport. To take full benefit of combined analyses of AMS-02 data, better nuclear data and a better handle on energy correlations in the data systematic are required. AMS-02 data on heavier species are eagerly awaited to further explore cosmic-ray propagation scenarios.

[32]  arXiv:2002.11422 [pdf, other]

Title: Can planetary rings explain the extremely low density of HIP 41378f?

Authors: B. Akinsanmi, N. C. Santos, J. P. Faria, M. Oshagh, S. C. C. Barros, A. Santerne, S. Charnoz

Comments: 9 figures, 8 pages, accepted by A&A

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

The presence of rings around a transiting planet can cause its radius to be overestimated and lead to an underestimation of its density if the mass is known. We employ a Bayesian framework to show that the anomalously low density ($\sim$0.09 g cm${^{-3}}$) of the transiting long-period planet HIP$\,$41378$\,f$ might be due to the presence of opaque circum-planetary rings. Given our adopted model priors and data from the K2 mission, we find the statistical evidence for the ringed planet scenario to be comparable to that of the planet-only scenario. The ringed planet solution suggests a larger planetary density of $\sim$1.23$\,$g$\,$cm$^{-3}$ similar to Uranus. The associated ring extends from 1.05 to 2.59 times the planetary radius and is inclined away from the sky-plane by $\sim$25$^\mathrm{o}$. Future high-precision transit observations of HIP$\,$41378$\,f$ would be necessary to confirm/dismiss the presence of planetary rings.

[33]  arXiv:2002.11427 [pdf, other]

Title: Magnetospheric return-current-heated atmospheres of rotation-powered millisecond pulsars

Authors: Tuomo Salmi, Valery F. Suleimanov, Joonas Nättilä, Juri Poutanen

Comments: 13 pages, 10 figures, submitted to A&A

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

We compute accurate atmosphere models of rotation-powered millisecond pulsars in which the polar caps of a neutron star (NS) are externally heated by magnetospheric return currents. The external ram pressure, energy losses, and stopping depth of the penetrating charged particles are computed self-consistently with the atmosphere model, instead of assuming a simplified deep-heated atmosphere in radiative equilibrium. We use exact Compton scattering formalism to model the properties of the emergent X-ray radiation. The deep-heating approximation is found to be valid only if most of the heat originates from ultra-relativistic bombarding particles with Lorentz factors $\gamma \gtrsim 100$. In the opposite regime, the atmosphere attains a distinct two-layer structure with an overheated optically thin skin on top of an optically thick cool plasma. The overheated skin strongly modifies the emergent radiation producing a Compton-upscattered high-energy tail in the spectrum and changes the radiation beaming pattern from limb darkening to limb brightening for emitted hard X-rays. This kind of drastic change in the emission properties can have a significant impact on the inferred NS pulse profile parameters as performed, for example, by Neutron star Interior Composition ExploreR (NICER). Finally, the connection between the energy distribution of the return current particles and the atmosphere emission properties offers a new tool for probing the exact physics of pulsar magnetospheres.

[34]  arXiv:2002.11460 [pdf, other]

Title: The 4th Fermi-GBM Gamma-Ray Burst Catalog: A Decade of Data

Authors: A. von Kienlin, C. A. Meegan, W. S. Paciesas, P. N. Bhat, E. Bissaldi, M. S. Briggs, E. Burns, W. H. Cleveland, M. H. Gibby, M. M. Giles, A. Goldstein, R. Hamburg, C. M. Hui, D. Kocevski, B. Mailyan, C. Malacaria, S. Poolakkil, R. D. Preece, O. J. Roberts, P. Veres, C. A. Wilson-Hodge

Comments: 273 pages, 10 figures, 8 tables. Accepted for publication in ApJS

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

We present the fourth in a series of catalogs of gamma ray bursts (GRBs) observed with Fermi's Gamma-Ray Burst Monitor (Fermi-GBM). It extends the six-year catalog by four more years, now covering the ten year time period from trigger enabling on 2008 July 12 to 2018 July 11. During this time period GBM triggered almost twice a day on transient events of which we identifyied 2356 as cosmic GRBs. Additional trigger events were due to solar are events, magnetar burst activities and terrestrial gamma-ray flashes. The intention of the GBM GRB catalog series is to provide updated information to the community on the most important observables of the GBM detected GRBs. For each GRB the location and main characteristics of the prompt emission, the duration, peak flux and fluence are derived. The latter two quantities are calculated for the 50-300 keV energy band, where the maximum energy release of GRBs in the instrument reference system is observed and also for a broader energy band from 10-1000 keV, exploiting the full energy range of GBM's low-energy detectors. Furthermore, information is given on the settings of the triggering criteria and exceptional operational conditions during years seven to ten in the mission. This fourth catalog is an official product of the Fermi-GBM science team, and the data files containing the complete results are available from the High-Energy Astrophysics Science Archive Research Center (HEASARC).

[35]  arXiv:2002.11502 [pdf, other]

Title: The importance of magnetic fields for the initial mass function of the first stars

Authors: Piyush Sharda, Christoph Federrath, Mark R. Krumholz

Comments: 17 pages, 9 figures, 3 tables; submitted to MNRAS

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

Magnetic fields play an important role for the formation of stars in both local and high-redshift galaxies. Recent studies of dynamo amplification in the first dark matter haloes suggest that significant magnetic fields were likely present during the formation of the first stars in the Universe at redshifts of 15 and above. In this work, we study how these magnetic fields potentially impact the initial mass function (IMF) of the first stars. We carry out 200 high-resolution, three-dimensional (3D), magnetohydrodynamic (MHD) simulations of the collapse of primordial clouds with different initial turbulent magnetic field strengths as predicted from turbulent dynamo theory in the early Universe, forming more than 1100 first stars in total. We detect a strong statistical signature of suppressed fragmentation in the presence of strong magnetic fields, leading to a dramatic reduction in the number of first stars with masses low enough that they might be expected to survive to the present day. Additionally, strong fields shift the transition point where stars go from being mostly single to mostly multiple to higher masses. However, irrespective of the field strength, individual simulations are highly chaotic, show different levels of fragmentation and clustering, and the outcome depends on the exact realisation of the turbulence in the primordial clouds. While the origin of primordial magnetic fields is still not fully understood, our work shows that primordial magnetic fields potentially have a larger impact on the primordial IMF than their counterparts have on the present-day IMF.

[36]  arXiv:2002.11567 [pdf, other]

Title: Search for a Variation of the Fine Structure around the Supermassive Black Hole in Our Galactic Center

Authors: A. Hees, T. Do, B. M. Roberts, A. M. Ghez, S. Nishiyama, R. O. Bentley, A. K. Gautam, S. Jia, T. Kara, J. R. Lu, H. Saida, S. Sakai, M. Takahashi, Y. Takamori

Comments: 7 pages + 10 pages appendix, 3 figures, version accepted for publication

Journal-ref: Phys. Rev. Letters 124, 081101, 2020

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

Searching for space-time variations of the constants of Nature is a promising way to search for new physics beyond General Relativity and the standard model motivated by unification theories and models of dark matter and dark energy. We propose a new way to search for a variation of the fine-structure constant using measurements of late-type evolved giant stars from the S-star cluster orbiting the supermassive black hole in our Galactic Center. A measurement of the difference between distinct absorption lines (with different sensitivity to the fine structure constant) from a star leads to a direct estimate of a variation of the fine structure constant between the star's location and Earth. Using spectroscopic measurements of 5 stars, we obtain a constraint on the relative variation of the fine structure constant below $10^{-5}$. This is the first time a varying constant of Nature is searched for around a black hole and in a high gravitational potential. This analysis shows new ways the monitoring of stars in the Galactic Center can be used to probe fundamental physics.

[37]  arXiv:2002.11586 [pdf, other]

Title: Development of an advanced Compton telescope for MeV-range gamma-ray astronomy

Authors: Adrien Laviron, Valentin Gourlaouen, Clarisse Hamadache, Corentin Hiver, Jürgen Kiener, Jean Peyré, Vincent Tatischeff

Comments: Conference proceedings of the Journ\'ees de Rencontre des Jeunes Chercheurs 2019, 24-30 November 2019, Logonna-Daoulas, FRANCE (5 pages, 7 figures)

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

An advanced Compton telescope appears to be the best instrument concept for the next generation gamma-ray space observatory in the MeV range. A first prototype of advanced Compton telescope is being developed to match the constraints of a nano satellite mission, with the scientific objective of measuring gamma-ray burst prompt emission polarization. Our instrumental developments for this project are focusing on the position-sensitive calorimeter module, made of a monolithic inorganic CeBr$_3$ scintillator read by a pixelated photodetector. 3D position reconstruction is obtained by deep-learning algorithms that have been optimized down to an uncertainty of 2 mm for each spatial direction.

[38]  arXiv:2002.11600 [pdf, other]

Title: An extended proto-cluster of galaxies surrounding SPT2349$-$56 at $z\,{=}\,4.3$

Authors: Ryley Hill, Scott Chapman, Douglas Scott, Yordanka Apostolovski, Manuel Aravena, Matthieu Bethermin, C. M. Bradford, Carlos de Breuck, Rebecca E. A. Canning, Chenxing Dong, Anthony Gonzalez, Thomas R. Greve, Christopher C. Hayward, Yashar Hezaveh, Katrina Litke, Matt Malkan, Daniel P. Marrone, Kedar Phadke, Cassie Reuter, Justin Spilker, Joaquin D. Vieira, Axel Weiss

Comments: Submitted to MNRAS Feb. 25, 2020

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

The $z\,{=}\,4.3$ overdensity SPT2349$-$56 has been proposed as one of the most actively star-forming proto-clusters known, and we have undertaken an extensive ALMA spectroscopic follow-up programme of this system to search for far infrared-luminous proto-cluster members via their [CII] 158$\,\mu$m and CO(4-3) line emission. In addition to robustly detecting the 14 previously published galaxies in this structure, we identify a further 15 associated galaxies at $z\,{=}\,4.3$. These proto-cluster members are distributed into a central core containing 23 galaxies extending out to 300$\,$kpc in diameter, and a northern extension, offset from the core by 400$\,$kpc and containing three galaxies. We discovered three additional galaxies in a red Herschel-SPIRE source 2$\,$Mpc from the main structure, suggesting the existence of many other sources at the same redshift as SPT2349$-$56 that are not yet detected in the limited coverage of our data. An analysis of the velocity distribution within the core indicates that this region may be a nearly virialized structure with a mass of (9$\pm$5)$\,{\times}\,$10$^{12}\,$M$_{\odot}$, while the two offset substructures show significant velocity offsets from the central structure. We calculate the [CII] and far-infrared number counts, and find evidence for a break in the [CII] luminosity function around 4$\,{\times}\,10^9\,$L$_{\odot}$. We estimate the average SFR density within the region of SPT2349$-$56 containing single-dish emission (a proper diametre of 720$\,$kpc), assuming spherical symmetry, to be roughly 40,000$\,$M$_{\odot}\,$yr$^{-1}\,$Mpc$^{-3}$; this is an order of magnitude greater than the most extreme examples seen in simulations.

[39]  arXiv:2002.11606 [pdf, other]

Title: Red Be stars in the Magellanic Clouds

Authors: Katherine Vieira, Alejandro García-Varela, Beatriz Sabogal

Comments: 12 pages, 10 figures, submitted to MNRAS

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

We revisit the subject of Be star candidates towards the Magellanic Clouds, previously studied by the authors using SPM4 proper motions. We obtain GAIA DR2 parallaxes and proper motions for 2357 and 994 LMC and SMC Be candidates, respectively. Parallaxes and proper motions vs. color V-I easily reveal the presence of the redder galactic contaminant foreground, as concluded in our previous work, but this time we do find a few red Be stars candidates consistent with being true Magellanic objects. A membership assessment to each Magellanic Cloud is done for each Be candidate, based on the distribution of their parallaxes and proper motions. From a compilation of published catalogues of spectroscopically confirmed Be stars, we found that 40 (LMC) and 64 (SMC) of these Be candidates, are in fact Be stars. Near infrared IRSF JHKs magnitudes were obtained for about 70% the Be stars candidates with GAIA DR2 astrometric data. Mid-infrared SAGE IRAC 3.6, 4.5, 5.8 and 8.0 $\mu$m magnitudes were obtained for about 85% as well. 6 LMC and 7 SMC confirmed Be stars show optical, near- or mid-infrared colours redder than what has been typically measured for Classical Be stars. Several of the Be candidates follow those redder-than-expected colours distributions suggesting the existence of more red Magellanic Be stars.

[40]  arXiv:2002.11630 [pdf, other]

Title: Cosmic Rates of Black Hole Mergers and Pair-Instability Supernovae from Chemically Homogeneous Binary Evolution

Authors: Lise du Buisson, Pablo Marchant, Philipp Podsiadlowski, Chiaki Kobayashi, Filipe B. Abdalla, Philip Taylor, Ilya Mandel, Selma E. de Mink, Takashi J. Moriya, Norbert Langer

Comments: 19 pages, 23 figures, 4 tables

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

During the first three observing runs of the Advanced gravitational-wave detector network, the LIGO/Virgo collaboration detected several black hole binary (BHBH) mergers. As the population of detected BHBH mergers grows, it will become possible to constrain different channels for their formation. Here we consider the chemically homogeneous evolution (CHE) channel in close binaries, by performing population synthesis simulations that combine realistic binary models with detailed cosmological calculations of the chemical and star-formation history of the Universe. This allows us to constrain population properties, as well as cosmological and aLIGO detection rates of BHBH mergers formed through this pathway. We predict a BHBH merger rate at redshift zero of $5.8 \hspace{1mm} \textrm{Gpc}^{-3} \textrm{yr}^{-1}$ through the CHE channel, to be compared with aLIGO's measured rate of ${53.2}_{-28.2}^{+55.8} \hspace{1mm} \text{Gpc}^{-3}\text{yr}^{-1}$, and find that eventual merger systems have BH masses in the range $17 - 43 \hspace{1mm} \textrm{M}_{\odot}$ below the pair-instability supernova (PISN) gap, and $>124 \hspace{1mm} \textrm{M}_{\odot}$ above the PISN gap. We further investigate the effects of momentum kicks during black hole formation, calculate cosmological and magnitude limited PISN rates and investigate the effects of high-redshift deviations in the star formation rate. We find that momentum kicks tend to increase delay times of BHBH systems, and our magnitude limited PISN rate estimates indicate that current deep surveys should be able to detect such events. Lastly, we find that our cosmological merger rate estimates change by at most $\sim 8\%$ for mild deviations of the star formation rate in the early Universe, and by up to $\sim 40\%$ for extreme deviations.

[41]  arXiv:2002.11652 [pdf, other]

Title: Exploring the Self Interacting Dark Matter Properties From Low Redshift Observations

Authors: Arvind Kumar Mishra

Comments: 30 pages, 7 figures. Comments and suggestions are welcome

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

The small scale observations indicate that the dark matter may be self-interacting. In this paper, we calculate the shear ($\eta$) and bulk viscosity ($\zeta$) of Self Interacting Dark Matter (SIDM) fluid, in kinetic theory formalism. Further, using the KSS bound on $\eta/\mathfrak{s}$, we derive a new upper limit on the ratio of dark matter self interaction cross section to its mass, $ \sigma/m $. Then, using the $ \sigma/m $ constraint, we show that KSS bound allows only sub-GeV mass of SIDM particle. Further, with the assumption of a power-law form of $\eta$ and $\zeta$, we study its evolution in the light of low redshift observations. We find that at the large redshift, the SIDM viscosity is small but at the small redshift it becomes sufficiently large and contributes significantly in cosmic dissipation. As a consequence, viscous SIDM can explain the low redshift observations and also consistent with the standard cosmological prediction.

[42]  arXiv:2002.11653 [pdf, other]

Title: Proper-Motion Membership Tests for Four Planetary Nebulae in Galactic Globular Clusters

Authors: Howard E. Bond (1 and 2), Andrea Bellini (2), Kailash C. Sahu (2) ((1) Pennsylvania State University, (2) Space Telescope Science Institute)

Comments: Submitted to Astronomical Journal

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

Four planetary nebulae (PNe) are considered to be probable members of Galactic globular clusters (GCs). These are Ps 1 = K648 in M15, GJJC 1 = IRAS 18333-2357 in M22, JaFu 1 in Palomar 6, and JaFu 2 in NGC 6441. In addition to lying close to the host GCs in the sky, all of these PNe have radial velocities that are consistent, within the errors, with cluster membership. The remaining membership criterion is whether the proper motions (PMs) of the central stars are in agreement with those of the host clusters. We have carried out the PM test for all four PNe. Two of the central stars--those of Ps 1 and GJJC 1--have PMs listed in the recent Gaia Data Release 2 (DR2). Their PMs are statistically consistent with cluster membership, although Ps 1 is a mild outlier; if confirmed by subsequent Gaia data, this could suggest that the central star received a "kick" during PN formation. For the other two PNe, we used archival Hubble Space Telescope (HST) images to derive the PMs of their nuclei. For JaFu 2, there are HST images at several epochs, and the measured PM of the nucleus is in excellent agreement with that of the host cluster. For JaFu 1 the available archival HST images are less optimal, but the measured PM for the central star is again statistically consistent with cluster membership.

[43]  arXiv:2002.11681 [pdf, other]

Title: Magnetic field screening process in a Kerr Black Hole

Authors: S. Campion, J. A.Rueda, G. Vereshchagin, S. S. Xue, R. Ruffini

Comments: 8 pages, 11 figures

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

It has been shown that a rotating BH immersed in a test background magnetic field, of initial strength $B_0$ and aligned parallel to the BH rotation axis, generates an induced electric field, that is proportional to the magnetic field. In this system, an huge number of pairs can be emitted by vacuum polarization process and start to be accelerated to high energies, mean this electric field, emitting synchrotron photons. In this paper we study the screening effect of magnetic and electric field due to the magnetic pair production process (hereafter MPP) ($\gamma+B\rightarrow e^{+}+e^{-}$) made by the created pairs. The principal results of this study are that: these combined processes of synchrotron emission by accelerated electrons and MPP can decrease magnetic field of several order of magnitude on a small time scale; exist a lower limit for the magnetic field after that it cannot be screened anymore.

[44]  arXiv:2002.11688 [pdf]

Title: Hemolithin: a Meteoritic Protein containing Iron and Lithium

Authors: Malcolm. W. McGeoch, Sergei Dikler, Julie E. M. McGeoch

Comments: 33 pages including 14 figures, 10 tables

Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Chemical Physics (physics.chem-ph)

This paper characterizes the first protein to be discovered in a meteorite. Amino acid polymers previously observed in Acfer 086 and Allende meteorites [1,2] have been further characterized in Acfer 086 via high precision MALDI mass spectrometry to reveal a principal unified structure of molecular weight 2320 Daltons that involves chains of glycine and hydroxy-glycine residues terminated by iron atoms, with additional oxygen and lithium atoms. Signal-to-noise ratios up to 135 have allowed the quantification of iron and lithium in the various MALDI fragments via the isotope satellites due to their respective minority isotopic masses 54Fe and 6Li. Analysis of the complete spectrum of isotopes associated with each molecular fragment shows 2H enhancements above terrestrial averaging 25,700 parts per thousand (sigma = 3,500, n=15), confirming extra-terrestrial origin and hence the existence of this molecule within the asteroid parent body of the CV3 meteorite class. The molecule is tipped by an iron-oxygen-iron grouping that in other terrestrial contexts has been proposed to be capable of absorbing photons and splitting water into hydroxyl and hydrogen moieties.

[45]  arXiv:2002.11689 [pdf, ps, other]

Title: The 10.5 year rotation period of the strongly magnetic rapidly oscillating Ap star HD 166473

Authors: Gautier Mathys, Viktor Khalack, John D. Landstreet

Comments: 12 pages, 8 figures. Accepted for publication in A&A. In the journal, at the request of the editor, the abstract will appear in traditional form, as shown in this header. This arXiv preprint features a structured version of the abstract, so that the LaTeX source could be successfully processed by arXiv

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

How magnetic fields contribute to the differentiation of the rotation rates of the Ap stars and affect the occurrence of non-radial pulsation in some of them are important open questions. Valuable insight can be gained into these questions by studying some of the most extreme examples of the processes at play. The super-slowly rotating rapidly oscillating Ap (roAp) star HD 166473 is such an example. We performed the first accurate determination of its rotation period, (3836 +/- 30)d, from the analysis of 56 measurements of the mean magnetic field modulus <B> based on high-resolution spectra acquired between 1992 and 2019 at various observatories and with various instrumental configurations. We complemented this analysis with the consideration of an inhomogeneous set of 21 determinations of the mean longitudinal magnetic field <B_z> spanning the same time interval. This makes HD 166473 one of only four Ap stars with a period longer than 10 years for which magnetic field measurements have been obtained over more than a full cycle. The variation curves of <B> and of <B_z> are well approximated by cosine waves. The magnetic field of HD 166473 only seems to deviate slightly from axisymmetry, but it definitely involves a considerable non-dipolar component. Among the stars with rotation periods longer than 1000 d for which magnetic field measurements with full phase coverage are available, HD 166473 has the strongest field. Its magnetic field is also one of the strongest known among roAp stars. Overall, the magnetic properties of HD 166473 do not seem fundamentally distinct from those of the faster-rotating Ap stars. However, considering as a group the eight Ap stars that have accuractely determined periods longer than 1000 d and whose magnetic variations have been characterised over a full cycle suggests that the angles between their magnetic and rotation axes tend to be systematically large.

[46]  arXiv:2002.11695 [pdf, other]

Title: Chromospheric evaporation and phase mixing of Alfvén waves in coronal loops

Authors: H.J. Van Damme, I. De Moortel, P. Pagano, C. D. Johnston

Comments: 11 pages, 12 figures, accepted for publication in A&A

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

Phase mixing of Alfv\'en waves has been studied extensively as a possible coronal heating mechanism but without the full thermodynamic consequences considered self-consistently. It has been argued that in some cases, the thermodynamic feedback of the heating could substantially affect the transverse density gradient and even inhibit the phase mixing process. In this paper, we use MHD simulations with the appropriate thermodynamical terms included to quantify the evaporation following heating by phase mixing of Alfv\'en waves in a coronal loop and the effect of this evaporation on the transverse density profile. The numerical simulations were performed using the Lare2D code. We set up a 2D loop model consisting of a field-aligned thermodynamic equilibrium and a cross-field (background) heating profile. A continuous, sinusoidal, high-frequency Alfv\'en wave driver was implemented. As the Alfv\'en waves propagate along the field, they undergo phase mixing due to the cross-field density gradient in the coronal part of the loop. We investigated the presence of field-aligned flows, heating from the dissipation of the phase-mixed Alfv\'en waves, and the subsequent evaporation from the lower atmosphere. We find that phase mixing of Alfv\'en waves leads to modest heating in the shell regions of the loop and evaporation of chromospheric material into the corona with upflows of the order of only 5-20 m/s. Although the evaporation leads to a mass increase in the shell regions of the loop, the effect on the density gradient and, hence, on the phase mixing process, is insignificant. This paper self-consistently investigates the effect of chromospheric evaporation on the cross-field density gradient and the phase mixing process in a coronal loop. We found that the effects in our particular setup (small amplitude, high frequency waves) are too small to significantly change the density gradient.

[47]  arXiv:2002.11707 [pdf, other]

Title: Can Late Dark Energy Transitions Raise the Hubble constant?

Authors: Giampaolo Benevento, Wayne Hu, Marco Raveri

Comments: 7 pages, 3 figures

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

Late times dark energy transitions at redshifts $z \ll 0.1$ can raise the predicted value of the Hubble constant to the SH0ES value, $74.03\pm 1.42$ (km s$^{-1}$ Mpc$^{-1})$ or more, while providing an equally good fit as $\Lambda$CDM at $67.73 \pm 0.41$ to higher redshift data, in particular from the cosmic microwave background and baryon acoustic oscillations. These models however do not fully resolve the true source of tension between the distance ladder and high redshift observations: the local calibration of supernovae luminosities well out into the Hubble flow. When tested in this manner by transferring the SH0ES calibration to the Pantheon supernovae dataset, the ability of such transitions to reduce the Hubble tension drops effectively to $69.17 \pm 1.09$. Such an analysis should also be used when testing any dynamical dark energy model which can produce similarly fine features in redshift or local void models.

Cross-lists for Thu, 27 Feb 20

[48]  arXiv:2002.11132 (cross-list from physics.space-ph) [pdf, other]

Title: Electron Heating in Perpendicular Low-Beta Shocks

Authors: Aaron Tran, Lorenzo Sironi

Comments: 6 pages, 4 figures; re-submitted. Supplemental material at this http URL

Subjects: Space Physics (physics.space-ph); High Energy Astrophysical Phenomena (astro-ph.HE)

Collisionless shocks heat electrons in the solar wind, interstellar blast waves, and hot gas permeating galaxy clusters. How much shock heating goes to electrons instead of ions, and what plasma physics controls electron heating? We simulate 2-D perpendicular shocks with a fully kinetic particle-in-cell code. For magnetosonic Mach number $\mathcal{M}_\mathrm{ms} \sim 1$-$10$ and plasma beta $\beta_\mathrm{p} \lesssim 4$, the post-shock electron/ion temperature ratio $T_\mathrm{e}/T_\mathrm{i}$ decreases from $1$ to $0.1$ with increasing $\mathcal{M}_\mathrm{ms}$. In a representative $\mathcal{M}_\mathrm{ms}=3.1$, $\beta_\mathrm{p}=0.25$ shock, electrons heat above adiabatic compression in two steps: ion-scale $E_\parallel = \vec{E} \cdot \hat{b}$ accelerates electrons into streams along $\vec{B}$, which then relax via two-stream-like instability. Shock rippling also allows quasi-static shock-normal electric fields to heat electrons; we find that quasi-static fields generally contribute half of the electron heating beyond adiabatic compression.

[49]  arXiv:2002.11133 (cross-list from nucl-th) [pdf, other]

Title: Finite-Temperature Quarkyonic Matter with an Excluded Volume Model for Nuclear Interactions

Authors: Srimoyee Sen, Neill C. Warrington

Comments: 17 pages, 6 figures

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

We compute finite temperature properties of a recently proposed "excluded volume" model of quarkyonic matter under thermodynamic conditions found in binary neutron star mergers. To do so, we extend this model by introducing finite temperature distribution functions and entropy functionals. The main effect of temperature is to decrease by a small amount the baryon density at which the quarkyonic phase emerges, and to increase the total density of quarks. To the extent this model describes reality, we conclude that hot environments such as neutron star mergers are more likely to host deconfined quark matter than their zero temperature counterparts.

[50]  arXiv:2002.11272 (cross-list from physics.plasm-ph) [pdf, ps, other]

Title: A class of three-dimensional gyroviscous magnetohydrodynamic models

Authors: Manasvi Lingam, Philip J. Morrison, Alexander Wurm

Comments: 22 pages; 0 figures

Subjects: Plasma Physics (physics.plasm-ph); Solar and Stellar Astrophysics (astro-ph.SR); Fluid Dynamics (physics.flu-dyn)

A Hamiltonian and Action Principle (HAP) formalism for deriving 3D gyroviscous magnetohydrodynamic models is presented. The uniqueness of the approach in constructing the gyroviscous tensor from first principles and its ability to explain the origin of the gyromap and the gyroviscous terms are highlighted. The procedure allows for the specification of free functions, which can be used to generate a wide range of gyroviscous models. Through the process of reduction, the noncanonical Hamiltonian bracket is obtained and briefly analyzed.

[51]  arXiv:2002.11496 (cross-list from gr-qc) [pdf, other]

Title: Cutoff-independent ergodic approximation to the generic three-body problem

Authors: Barak Kol

Comments: 10 pages

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

The gravitational three-body problem is generically chaotic and negative energy motions generically decay to a binary + free body. Within the ergodic approximation a statistical theory was introduced and a probability distribution over outcomes was determined. That distribution depends on a single adjustable parameter, the strong interaction radius. Here this cutoff is removed while keeping the probabilities finite. The associated expression and its derivation simplify. As an application, marginalized probability distributions are determined for energy, angular momentum and eccentricity as well as the ejection probability for each one of the masses. Two simpler limits are discussed corresponding to low and high dimensionless total angular momentum.

Replacements for Thu, 27 Feb 20

[52]  arXiv:1709.06535 (replaced) [pdf, other]

Title: Observational Signatures of Gamma Rays from Bright Blazars and Wakefield Theory

Authors: N. E. Canac, K. N. Abazajian, T. Tajima (UC Irvine), T. Ebisuzaki (RIKEN), S. Horiuchi (Virginia Tech)

Comments: 10 pages, 6 figures. matches version to be published in MNRAS

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

[53]  arXiv:1807.00397 (replaced) [pdf, other]

Title: Extended Cosmology in Palatini f(R)-theories

Authors: Paolo Pinto, Leonardo Del Vecchio, Lorenzo Fatibene, Marco Ferraris

Comments: 24 pages, 14 figures

Journal-ref: Journal of Cosmology and Astroparticle Physics, Vol. 2018, No. 11, 044, 27.11.2018

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

[54]  arXiv:1809.05608 (replaced) [pdf, other]

Title: Chimera: A massively parallel code for core-collapse supernova simulation

Authors: Stephen W. Bruenn, John M. Blondin, W. Raphael Hix, Eric J. Lentz, O. E. Bronson Messer, Anthony Mezzacappa, Eirik Endeve, J. Austin Harris, Pedro Marronetti, Reuben D. Budiardja, Merek A. Chertkow, Ching-Tsai Lee

Comments: Accepted for publication in ApJS

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

[55]  arXiv:1903.06717 (replaced) [pdf, other]

Title: A new method to constrain the origins of dark matter-free galaxies and their unusual globular clusters

Authors: Nathan Leigh, Giacomo Fragione

Comments: 12 pages, 5 figures, 2 table, accepted by ApJ

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

[56]  arXiv:1903.10758 (replaced) [pdf, ps, other]

Title: Growth index of matter perturbations in the light of Dark Energy Survey

Authors: Spyros Basilakos, Fotios K. Anagnostopoulos

Comments: 8 pages, 3 figures, discussion added, to appear in European Physical Journal C (EPJC)

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

[57]  arXiv:1905.11414 (replaced) [pdf, other]

Title: How to Quench a Dwarf Galaxy: The Impact of Inhomogeneous Reionization on Dwarf Galaxies and Cosmic Filaments

Authors: Harley Katz, Marius Ramsoy, Joakim Rosdahl, Taysun Kimm, Jeremy Blaizot, Martin G. Haehnelt, Leo Michel-Dansac, Thibault Garel, Clotilde Laigle, Julien Devriendt, Adrianne Slyz

Comments: 21 pages, 11 figures, MNRAS Accepted

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

[58]  arXiv:1906.03190 (replaced) [pdf, ps, other]

Title: Evolution of black hole shadow in the presence of ultralight bosons

Authors: Rittick Roy, Urjit A. Yajnik

Comments: New table added with improvement over previous model, version published in Phys. Lett. B

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

[59]  arXiv:1906.12347 (replaced) [pdf, other]

Title: Consistency of the local Hubble constant with the cosmic microwave background

Authors: Lucas Lombriser

Comments: 8 pages, 2 figures; v2: appendix with derivations added; v3: published version with additional comments on H0LiCOW measurement

Journal-ref: Phys. Lett. B 803, 135303 (2020)

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

[60]  arXiv:1908.01918 (replaced) [pdf, ps, other]

Title: Properties of strange quark stars with isovector interactions

Authors: He Liu, Jun Xu, Che Ming Ko

Comments: 7 pages, 8 figures, minor modifications on references and corresponding discussions

Subjects: Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR); High Energy Physics - Phenomenology (hep-ph)

[61]  arXiv:1908.03026 (replaced) [pdf, ps, other]

Title: The 31-year Rotation History of the Millisecond Pulsar J1939+2134 (B1937+21)

Authors: M. Vivekanand

Journal-ref: M. Vivekanand 2020 ApJ 890 143

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

[62]  arXiv:1908.10595 (replaced) [pdf, other]

Title: Cosmological constraints from the redshift dependence of the Alcock-Paczynski effect: a study on the systematics estimation

Authors: Qinglin Ma, Yiqing Guo, Xiao-Dong Li, Xin Wang, Haitao Miao, Zhigang Li, Cristiano G. Sabiu, Hyunbae Park

Comments: 13 pages, 6 figures. Accepted to ApJ

Journal-ref: The Astrophysical Journal, 890 92, 2020 February 20

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

[63]  arXiv:1910.00521 (replaced) [pdf, other]

Title: Trans-Planckian Censorship, Inflation and Dark Matter

Authors: Tommi Tenkanen

Comments: 9 pages, 1 figure. v2: Added a figure, some clarifications, and discussion. Accepted for publication in Phys. Rev. D

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

[64]  arXiv:1910.08544 (replaced) [pdf, other]

Title: Secular effects of Ultralight Dark Matter on Binary Pulsars

Authors: Diego Blas, Diana López Nacir, Sergey Sibiryakov

Comments: 24 pages, 3 figures, 3 tables; in v2 we introduced new clarifications, updated fig. 3 to include current bounds and agrees with the published version

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

[65]  arXiv:1910.12239 (replaced) [pdf, other]

Title: Pulsar Timing Array Constraints on Primordial Black Holes with NANOGrav 11-Year Data Set

Authors: Zu-Cheng Chen, Chen Yuan, Qing-Guo Huang

Comments: 7 pages, 2 table, 2 figures; Typos and errors corrected; replaced by refined figures

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)

[66]  arXiv:1910.13440 (replaced) [pdf, other]

Title: Identifying Exo-Earth Candidates in Direct Imaging Data through Bayesian Classification

Authors: Alex Bixel, Dániel Apai

Comments: 23 pages, 10 figures; published in AJ; re-submitted on 26 Feb 2020 to correct a typo in the metadata (no changes to the manuscript)

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

[67]  arXiv:1911.05311 (replaced) [pdf, ps, other]

Title: Gravitational lensing signature of matter distribution around Schwarzschild black hole

Authors: Harsha Miriam Reji, Mandar Patil

Comments: 42 pages, 7 figures, updated version

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

[68]  arXiv:1911.08912 (replaced) [pdf, other]

Title: Extreme & High Synchrotron Peak Blazars beyond 4FGL: The 2BIGB $\rm γ$-ray catalogue

Authors: Bruno Arsioli, Yu-Ling Chang, Blessing Musiimenta

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

[69]  arXiv:1911.11823 (replaced) [pdf, ps, other]

Title: Ringing of the regular black-hole/wormhole transition

Authors: M. S. Churilova, Z. Stuchlik

Comments: 8 pages, 4 figures, revtex, the version accepted for publication in Classical and Quantum Gravity, references added

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

[70]  arXiv:1911.12977 (replaced) [pdf, other]

Title: Positron Excess from Cosmic Ray Interactions in Galactic Molecular Clouds

Authors: Agnibha De Sarkar, Sayan Biswas, Nayantara Gupta

Comments: 20 pages, 5 figures, 5 tables

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

[71]  arXiv:1911.13088 (replaced) [pdf, other]

Title: Calibration and 21-cm Power Spectrum Estimation in the Presence of Antenna Beam Variations

Authors: Ronniy C. Joseph, C. M. Trott, R. B. Wayth, A. Nasirudin

Comments: 14 pages, 8 figures. Accepted for publication in MNRAS December 2019. Erratum submitted on 20 February 2020

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

[72]  arXiv:1912.02191 (replaced) [pdf, other]

Title: Is the expansion of the universe accelerating? All signs still point to yes a local dipole anisotropy cannot explain dark energy

Authors: David Rubin, Jessica Heitlauf

Comments: Accepted for publication in ApJ

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

[73]  arXiv:1912.05555 (replaced) [pdf, other]

Title: It is Feasible to Directly Measure Black Hole Masses in the First Galaxies

Authors: Hamsa Padmanabhan (CITA), Abraham Loeb (Harvard)

Comments: 9 pages, 3 figures; version accepted for publication in JCAP

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

[74]  arXiv:1912.06120 (replaced) [pdf, other]

Title: Solar Flare Intensity Prediction with Machine Learning Models

Authors: Zhenbang Jiao, Hu Sun, Xiantong Wang, Ward Manchester, Tamas Gombosi, Alfred Hero, Yang Chen

Comments: 28 pages, 15 figures

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

[75]  arXiv:1912.10354 (replaced) [pdf, other]

Title: The Broad-lined Ic Supernova ZTF18aaqjovh (SN 2018bvw): An Optically-discovered Engine-driven Supernova Candidate with Luminous Radio Emission

Authors: Anna Y. Q. Ho (1), Alessandra Corsi (2), S. Bradley Cenko (3 and 4), Francesco Taddia (5), S. R. Kulkarni (1), Scott Adams (1), Kishalay De (1), Richard Dekany (6), Dmitry D. Frederiks (7), Christoffer Fremling (1), V. Zach Golkhou (8 and 9), Thomas Kupfer (10), Russ R. Laher (11), Ashish Mahabal (1 and 12), Frank J. Masci (11), Adam A. Miller (13 and 14), James D. Neill (6), Daniel Reiley (6), Reed Riddle (6), Anna Ridnaia (7), Ben Rusholme (11), Yashvi Sharma (1), Jesper Sollerman (5), Maayane T. Soumagnac (15 and 16), Dmitry S. Svinkin (7), David L. Shupe (11) ((1) Cahill Center for Astrophysics, Caltech, (2) Texas Tech University, (3) NASA Goddard, (4) University of Maryland, (5) Stockholm University, (6) Caltech Optical Observatories, (7) Ioffe Institute, (8) DIRAC Institute, University of Washington, (9) The eScience Institute, University of Washington, (10) Kavli Institute for Theoretical Physics, UCSB, (11) IPAC, Caltech, (12) Center for Data Driven Discovery, Caltech, (13) CIERA, Northwestern, (14) Adler Planetarium, (15) LBNL, (16) Weizmann Institute of Science)

Comments: 15 pages, 8 figures. Resubmitted to the Astrophysical Journal on 25 Feb 2019

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

[76]  arXiv:1912.10945 (replaced) [pdf, other]

Title: A nonthermal bomb explains the near-infrared superflare of Sgr A*

Authors: Eduardo M. Gutiérrez, Rodrigo Nemmen, Fabio Cafardo

Comments: 6 pages, 3 figures, accepted for publication in ApJL

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

[77]  arXiv:2001.00095 (replaced) [pdf, other]

Title: Creation and Evolution of Impact-generated Reduced Atmospheres of Early Earth

Authors: Kevin Zahnle (1), Roxana Lupu (2), David Catling, Nick Wogan (3) ((1) NASA Ames Research Center, (2) BAER Insititute, (3) Dept. of Earth and Space Sciences, University of Washington)

Comments: Submitted 31 Dec 2019 to "The Planetary Science Journal." Accepted 10 Feb 2020

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

[78]  arXiv:2001.02971 (replaced) [pdf, other]

Title: The Onset of 3D Magnetic Reconnection and Heating in the Solar Corona

Authors: James Leake, Lars Daldorff, James Klimchuk

Comments: 11 pages9 figures

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

[79]  arXiv:2001.04065 (replaced) [pdf, other]

Title: Constraints on the Emission of Gamma Rays from M31 with HAWC

Authors: HAWC Collaboration: A. Albert, R. Alfaro, C. Alvarez, J. C. Arteaga-Velázquez, K. P. Arunbabu, D. Avila Rojas, H. A. Ayala Solares, E. Belmont-Moreno, S. Y. BenZvi, C. Brisbois, K. S. Caballero-Mora, T. Capistrán, A. Carramiñana, S. Casanova, U. Cotti, J. Cotzomi, S. Coutiño de León, E. De la Fuente, C. de León, S. Dichiara, B. L. Dingus, M. A. DuVernois, K. Engel, C. Espinoza, H. Fleischhack, N. Fraija, A. Galván-Gámez, D. García-Aguilar, J. A. García-González, F. Garfias, M. M. González, J. A. Goodman, J. P. Harding, S. Hernandez, B. Hona, D. Huang, F. Hueyotl-Zahuantitla, P. Hüntemeyer, A. Iriarte, A. Jardin-Blicq, V. Joshi, D. Kieda, W. H. Lee, H. León Vargas, A. L. Longinotti, G. Luis-Raya, K. Malone, S. S. Marinelli, et al. (36 additional authors not shown)

Comments: Accepted for publication in ApJ

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

[80]  arXiv:2001.08667 (replaced) [pdf, other]

Title: Stability analysis and constraints on interacting viscous cosmology

Authors: A. Hernández-Almada, Miguel A. García-Aspeitia, Juan Magaña, V. Motta

Comments: Accepted for publication in PRD

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

[81]  arXiv:2001.09152 (replaced) [pdf, ps, other]

Title: Distant foreground and the Planck-derived Hubble constant

Authors: V.N. Yershov, A.A. Raikov, N.Yu. Lovyagin, N.P.M. Kuin, E.A. Popova

Comments: 5 pages, 4 figures, 1 table

Journal-ref: Monthly Notices of the Royal Astronomical Society, 2020, 492, 5052-5056

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

[82]  arXiv:2002.03285 (replaced) [pdf, other]

Title: Pulsar timing array signals induced by black hole binaries in relativistic eccentric orbits

Authors: Abhimanyu Susobhanan, Achamveedu Gopakumar, George Hobbs, Stephen R. Taylor

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

[83]  arXiv:2002.08353 (replaced) [pdf, other]

Title: ZFIRE: Measuring Electron Density with [OII] as a function of environment at z = 1.62

Authors: Anishya Harshan, Anshu Gupta, Kim-Vy Tran, Leo Y. Alcorn, Tiantian Yuan, Glenn G. Kacprzak, Themiya Nanayakkara, Karl Glazebrook, Lisa J. Kewley, Ivo Labb'e, Casey Papovich

Comments: 18 Pages, 6 figures, 3 tables, Accepted for publication in Astrophysical Journal

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

[84]  arXiv:2002.09251 (replaced) [pdf, ps, other]

Title: Evidence for radio and X-ray auroral emissions from the magnetic B-type star rho Oph A

Authors: P. Leto, C. Trigilio, F. Leone, I. Pillitteri, C.S. Buemi, L. Fossati, F. Cavallaro, L.M. Oskinova, R. Ignace, J. Krticka, G. Umana, G. Catanzaro, A. Ingallinera, F. Bufano, C. Agliozzo, N.M. Phillips, L. Cerrigone, S. Riggi, S. Loru, M. Munari, M. Gangi, M. Giarrusso, J. Robrade

Comments: 20 pages, 13 figures; accepted to MNRAS

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

[85]  arXiv:2002.10256 (replaced) [pdf, other]

Title: Classification of Blazar Candidates of Uncertain Type from the Fermi LAT 8-Year Source Catalog with an Artificial Neural Network

Authors: Miloš Kovačević, Graziano Chiaro, Sara Cutini, Gino Tosti

Comments: Minor edits in wording and references

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

[86]  arXiv:2002.10601 (replaced) [pdf, other]

Title: Comment on "Collision and radiative processes in emission of atmospheric carbon dioxide"

Authors: M. Lino da Silva, J. Vargas

Comments: 12 pages, 5 figures

Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Atmospheric and Oceanic Physics (physics.ao-ph)

[87]  arXiv:2002.10834 (replaced) [pdf, other]

Title: Validation of Selection Function, Sample Contamination and Mass Calibration in Galaxy Cluster Samples

Authors: S. Grandis, M. Klein, J. J. Mohr, S. Bocquet, M. Paulus, T. M. C. Abbott, M. Aguena, S. Allam, J. Annis, B. A. Benson, E. Bertin, S. Bhargava, D. Brooks, D. L. Burke, A. Carnero Rosell, M. Carrasco Kind, J. Carretero, R. Capasso, M. Costanzi, L. N. da Costa, J. De Vicente, S. Desai, J. P. Dietrich, P. Doel, T. F. Eifler, S. Everett, A. E. Evrard, B. Flaugher, P. Fosalba, J. Frieman, J. García-Bellido, E. Gaztanaga, D. W. Gerdes, D. Gruen, R. A. Gruendl, J. Gschwend, G. Gutierrez, W. G. Hartley, S. R. Hinton, D. L. Hollowood, K. Honscheid, D. J. James, T. Jeltema, K. Kuehn, N. Kuropatkin, M. Lima, M. A. G. Maia, J. L. Marshall, P. Melchior, F. Menanteau, R. Miquel, R. L. C. Ogando, A. Palmese, F. Paz-Chinchón, A. A. Plazas, A. K. Romer, A. Roodman, E. Sanchez, A. Saro, V. Scarpine, et al. (13 additional authors not shown)

Comments: 28 pages, 23 figure

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

[88]  arXiv:2002.11083 (replaced) [pdf, other]

Title: Deformation of the gravitational wave spectrum by density perturbations

Authors: Valerie Domcke, Ryusuke Jinno, Henrique Rubira

Comments: 30 pages, 8 figures; figure 3 replaced in v2

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

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