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New submissions for Tue, 10 Dec 19

[1]  arXiv:1912.03314 [pdf, other]

Title: ALMA and NACO observations towards the young exoring transit system J1407 (V1400 Cen)

Authors: M. A. Kenworthy, P. D. Klaassen, M. Min, N. van der Marel, A. J. Bohn, M. Kama, A. Triaud, A. Hales, J. Monkiewicz, E. Scott, E. E. Mamajek

Comments: Accepted for publication in A&A (6 pages, 5 figures). Reduced data and reduction scripts on GitHub at this https URL

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

Our aim was to directly detect the thermal emission of the putative exoring system responsible for the complex deep transits observed in the light curve for the young Sco-Cen star 1SWASP J140747.93-394542.6 (V1400 Cen, hereafter J1407), confirming it as the occulter seen in May 2007, and to determine its orbital parameters with respect to the star. We used the Atacama Large Millimeter/submillimeter Array (ALMA) to observe the field centred on J1407 in the 340 GHz (Band 7) continuum in order to determine the flux and astrometric location of the ring system relative to the star. We used the VLT/NACO camera to observe the J1407 system in March 2019 and to search for the central planetary mass object at thermal infrared wavelengths. We detect no point source at the expected location of J1407, and derive an upper limit $3\sigma$ level of $57.6~\mu\rm{Jy}$. There is a point source detected at an angular separation consistent with the expected location for a free-floating ring system that occulted J1407 in May 2007, with a flux of $89~\mu\rm{Jy}$ consistent with optically thin dust surrounding a massive substellar companion. At 3.8 microns with the NACO camera, we detect the star J1407 but no other additional point sources within 1.3 arcseconds of the star, with a lower bound on the sensitivity of $6M_{Jup}$ at the location of the ALMA source, and down to $4M_{Jup}$ in the sky background limit. The ALMA upper limit at the location of J1407 implies that a hypothesised bound ring system is composed of dust smaller than $1\rm{~mm}$ in size, implying a young ring structure. The detected ALMA source has multiple interpretations, including: (i) it is an unbound substellar object surrounded by warm dust in Sco-Cen with an upper mass limit of $6M_{Jup}$, or (ii) it is a background galaxy.

[2]  arXiv:1912.03315 [pdf, ps, other]

Title: Chandra Observations of High Energy X-ray Sources Discovered by INTEGRAL

Authors: John A. Tomsick (SSL/UCB), Arash Bodaghee (GCSU), Sylvain Chaty (AIM/CEA/CNRS and APC), Maica Clavel (Univ. Grenoble Alpes), Francesca M. Fornasini (CfA), Jeremy Hare (SSL/UCB and GSFC), Roman Krivonos (SRI), Farid Rahoui (Independent), Jerome Rodriguez (AIM/CEA/CNRS)

Comments: Accepted by ApJ

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

The International Gamma-Ray Astrophysics Laboratory (INTEGRAL) satellite has detected in excess of 1000 sources in the ~20-100 keV band during its surveys of the sky over the past 17 years. We obtained 5 ks observations of 15 unclassified IGR sources with the Chandra X-ray Observatory in order to localize them, to identify optical/IR counterparts, to measure their soft X-ray spectra, and to classify them. For 10 of the IGR sources, we detect Chandra sources that are likely (or in some cases certain) to be the counterparts. IGR J18007-4146 and IGR J15038-6021 both have Gaia parallax distances, placing them at 2.5+0.5-0.4 and 1.1+1.5-0.4 kpc, respectively. We tentatively classify both of them as intermediate polar-type Cataclysmic Variables. Also, IGR J17508-3219 is likely to be a Galactic source, but it is unclear if it is a Dwarf Nova or another type of transient. For IGR J17118-3155, we provide a Chandra localization, but it is unclear if the source is Galactic or extragalactic. Based on either near-IR/IR colors or the presence of extended near-IR emission, we classify four sources as Active Galactic Nuclei (IGR J16181-5407, IGR J16246-4556, IGR J17096-2527, and IGR J19294+1327), and IGR J20310+3835 and IGR J15541-5613 are AGN candidates. In addition, we identified an AGN in the INTEGRAL error circle of IGR J16120-3543 that is a possible counterpart.

[3]  arXiv:1912.03316 [pdf, other]

Title: Stars made in outflows may populate the stellar halo of the Milky Way

Authors: Sijie Yu, James S. Bullock, Andrew Wetzel, Robyn E. Sanderson, Andrew S. Graus, Michael Boylan-Kolchin, Anna M. Nierenberg, Michael Y. Gurdić, Philip F. Hopkins, Dušan Kereš, Claude-André Faucher-Giguère

Comments: 19 pages, 20 figures, submitted to MNRAS

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

We study stellar-halo formation using six Milky Way-mass galaxies in FIRE-2 cosmological zoom simulations. We find that $5-40\%$ of the outer ($50-300$ kpc) stellar halo in each system consists of $\textit{in-situ}$ stars that were born in outflows from the main galaxy. Outflow stars originate from gas accelerated by super-bubble winds, which can be compressed, cool, and form co-moving stars. The majority of these stars remain bound to the halo and fall back with orbital properties similar to the rest of the stellar halo at $z=0$.In the outer halo, outflow stars are more spatially homogeneous, metal rich, and alpha-element-enhanced than the accreted stellar halo. At the solar location, up to $\sim 10 \%$ of our kinematically-identified halo stars were born in outflows; the fraction rises to as high as $\sim 40\%$ for the most metal-rich local halo stars ([Fe/H] $> -0.5$). We conclude that the Milky Way stellar halo could contain local counterparts to stars that are observed to form in molecular outflows in distant galaxies. Searches for such a population may provide a new, near-field approach to constraining feedback and outflow physics. A stellar halo contribution from outflows is a phase-reversal of the classic halo formation scenario of Eggen, Lynden-Bell $\&$ Sandange, who suggested that halo stars formed in rapidly $\textit{infalling}$ gas clouds. Stellar outflows may be observable in direct imaging of external galaxies and could provide a source for metal-rich, extreme velocity stars in the Milky Way.

[4]  arXiv:1912.03328 [pdf, other]

Title: Constraining properties of the next nearby core-collapse supernova with multi-messenger signals

Authors: MacKenzie L. Warren, Sean M. Couch, Evan P. O'Connor, Viktoriya Morozova

Comments: 23 pages, 15 figures, 8 tables, 462 explosions, 2.7e6 neutrinos. Submitted to AAS Journals

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

With the advent of modern neutrino and gravitational wave detectors, the promise of multi-messenger detections of the next galactic core-collapse supernova has become very real. Such detections will give insight into the core-collapse supernova mechanism, the structure of the progenitor star, and may resolve longstanding questions in fundamental physics. In order to properly interpret these detections, a thorough understanding of the landscape of possible core-collapse supernova events, and their multi-messenger signals, is needed. We present detailed predictions of neutrino and gravitational wave signals from 1D simulations of stellar core collapse, spanning the landscape of core-collapse progenitors from $9-120\,\mathrm{M}_{\odot}$. In order to achieve explosions in 1D, we use the STIR model, which includes the effects of turbulence and convection in 1D supernova simulations to mimic the 3D explosion mechanism. We study the gravitational wave emission from the 1D simulations using an astroseismology analysis of the proto-neutron star. We find that the neutrino and gravitational wave signals are strongly correlated with the structure of the progenitor star and remnant compact object. Using these correlations, future detections of the first few seconds of neutrino and gravitational wave emission from a galactic core-collapse supernova may be able to provide constraints on stellar evolution independent of pre-explosion imaging and the mass of the compact object remnant prior to fallback accretion.

[5]  arXiv:1912.03340 [pdf, other]

Title: Using the Stokes V widths of Fe I lines for diagnostics of the intrinsic solar photospheric magnetic field

Authors: M. Gordovskyy, S. Shelyag, P.K. Browning, V.G. Lozitsky

Comments: Accepted for publication in Astronomy and Astrophysics

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

The goal of this study is to explore a novel method for the solar photospheric magnetic field diagnostics using Stokes V widths of different magnetosensitive Fe~I spectral lines. We calculate Stokes I and V profiles of several Fe I lines based on a one-dimensional photospheric model VAL C using the NICOLE radiative transfer code. These profiles are used to produce calibration curves linking the intrinsic magnetic field values with the widths of blue peaks of Stokes V profiles. The obtained calibration curves are then tested using the Stokes profiles calculated for more realistic photospheric models based on MHD models of magneto-convection. It is shown that the developed Stokes V widths (SVW) method can be used with various optical and near-infrared lines. Out of six lines considered in this study, FeI 6301 line appears to be the most effective: it is sensitive to fields over ~200G and does not show any saturation up to ~2kG. Other lines considered can also be used for the photospheric field diagnostics with this method, however, only in narrower field value ranges, typically from about 100G to 700-1000G. The developed method can be a useful alternative to the classical magnetic line ratio method, particularly when the choice of lines is limited.

[6]  arXiv:1912.03351 [pdf, other]

Title: Constraining the masses of planets in protoplanetary discs from the presence or absence of vortices -- Comparison with ALMA observations

Authors: Paul Hallam, Sijme-Jan Paardekooper

Comments: 13 pages, 8 figures

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

A massive planet in a protoplanetary disc will open a gap in the disc material. A steep gap edge can be hydrodynamically unstable, which results in the formation of vortices that can act as tracers for the presence of planets in observational results. However, in a viscous disc, the potential formation of these vortices is dependent on the timescale over which the massive planet accretes mass and with a sufficiently long timescale it is possible for no vortices to form. Hence, there is a connection between the presence of vortices and the growth timescale of the planet and it may therefore be possible to exclude a planetary interpretation of observed structure from the absence of vortices. We have investigated the effect of the planet growth timescale on vortex formation for a range of planet masses and viscosities and have found an approximate relation between the planet mass, viscosity and planet growth timescale for which vortices are not formed within the disc. We then interpret these results in the light of recent observations. We have also found that planets do not need to be close to a Jupiter mass to form vortices in the disc if these discs have low viscosity, as these can be caused by planets as small as a few Neptune masses.

[7]  arXiv:1912.03371 [pdf, other]

Title: Statistics and Polarization of Type III Radio Bursts Observed in the Inner Heliosphere

Authors: Marc Pulupa, Stuart D. Bale, Samuel T. Badman, John W. Bonnell, Anthony W. Case, Thierry Dudok de Wit, Keith Goetz, Peter R. Harvey, Alexander M. Hegedus, Justin C. Kasper, Kelly E. Korreck, Vladimir Krasnoselskikh, Davin Larson, Alain Lecacheux, Roberto Livi, Robert J. MacDowall, Milan Maksimovic, David M. Malaspina, Juan Carlos Martínez Oliveros, Nicole Meyer-Vernet, Michel Moncuquet, Michael Stevens, Phyllis Whittlesey

Comments: 12 pages, 7 figures, to be published in ApJS

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

We present initial results from the Radio Frequency Spectrometer (RFS), the high frequency component of the FIELDS experiment on the Parker Solar Probe (PSP). During the first PSP solar encounter (2018 November), only a few small radio bursts were observed. During the second encounter (2019 April), copious Type III radio bursts occurred, including intervals of radio storms where bursts occurred continuously. In this paper, we present initial observations of the characteristics of Type III radio bursts in the inner heliosphere, calculating occurrence rates, amplitude distributions, and spectral properties of the observed bursts. We also report observations of several bursts during the second encounter which display circular polarization in the right hand polarized sense, with a degree of polarization of 0.15-0.38 in the range from 8-12 MHz. The degree of polarization can be explained either by depolarization of initially 100% polarized $o$-mode emission, or by direct generation of emission in the $o$ and $x$-mode simultaneously. Direct in situ observations in future PSP encounters could provide data which can distinguish these mechanisms.

[8]  arXiv:1912.03378 [pdf, other]

Title: Full Transport General Relativistic Radiation Magnetohydrodynamics for Nucleosynthesis in Collapsars

Authors: Jonah M. Miller, Trevor M. Sprouse, Christopher L. Fryer, Benjamin R. Ryan, Joshua C. Dolence, Matthew R. Mumpower, Rebecca Surman

Comments: 10 pages, 9 figures

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

We model a compact black hole-accretion disk system in the collapsar scenario with full transport, frequency dependent, general relativistic radiation magnetohydrodynamics. We examine whether or not winds from a collapsar disk can undergo rapid neutron capture (r-process) nucleosynthesis and significantly contribute to solar r-process abundances. We find the inclusion of accurate transport has significant effects on outflows, raising the electron fraction above $Y_e \sim 0.3$ and preventing third peak r-process material from being synthesized. We compare our model to semi-analytic expectations and argue that accurate neutrino transport and realistic initial and boundary conditions are required to capture the dynamics and nucleosynthetic outcome of a collapsar.

[9]  arXiv:1912.03382 [pdf, other]

Title: The AGN broad line region as a clumpy turbulent outflow: a physical basis for LOC modeling

Authors: Tim Waters, Hui Li

Comments: Submitted to ApJ Letters

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

Many studies have considered the roles of clouds, outflows, and turbulence in producing the broad emission and absorption lines in the spectra of active galactic nuclei (AGNs). However, these are often treated as separate or even competing models. Here, we consider the possibility that AGN clouds are condensations formed within the thermally unstable zones of outflows and then compare the typical sizes of such condensations with the injection scale $k_0^{-1} \sim L_0$ of turbulence, where $L_0$ is assumed to be the scale height of a representative global outflow model. We find that for broad line region (BLR) parameters, clouds are many orders of magnitude smaller than $L_0$ and this has the following implication: BLR cloud dynamics can be modeled using a local approximation through the use of multiphase turbulence simulations of X-ray irradiated plasmas. We present the first such 3D local clumpy turbulent outflow simulations. We show that the condensations share the same type of selection effects characterizing the locally optimally emitting cloud (LOC) scenario, thereby offering a physical interpretation for the LOC model and accounting for its almost uncanny successes. The ubiquitous presence of emission line regions in AGNs can be simply explained as the natural outcome of there being a multiphase interval of $k$-space within the inertial range of a turbulent cascade.

[10]  arXiv:1912.03384 [pdf, ps, other]

Title: Observations of the 2019 April 4 Solar Energetic Particle Event at the Parker Solar Probe

Authors: R. A. Leske, E. R. Christian, C. M. S. Cohen, A. C. Cummings, A. J. Davis, M. I. Desai, J. Giacalone, M. E. Hill, C. J. Joyce, S. M. Krimigis, A. W. Labrador, O. Malandraki, W. H. Matthaeus, D. J. McComas, R. L. McNutt Jr., R. A. Mewaldt, D. G. Mitchell, A. Posner, J. S. Rankin, E. C. Roelof, N. A. Schwadron, E. C. Stone, J. R. Szalay, M. E. Wiedenbeck, A. Vourlidas, S. D. Bale, R. J. MacDowall, M. Pulupa, J. C. Kasper, R. C. Allen, A. W. Case, K. E. Korreck, R. Livi, M. L. Stevens, P. Whittlesey, B. Poduval

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

A solar energetic particle event was detected by the Integrated Science Investigation of the Sun (ISOIS) instrument suite on Parker Solar Probe (PSP) on 2019 April 4 when the spacecraft was inside of 0.17 au and less than 1 day before its second perihelion, providing an opportunity to study solar particle acceleration and transport unprecedentedly close to the source. The event was very small, with peak 1 MeV proton intensities of ~0.3 particles (cm^2 sr s MeV)^-1, and was undetectable above background levels at energies above 10 MeV or in particle detectors at 1 au. It was strongly anisotropic, with intensities flowing outward from the Sun up to 30 times greater than those flowing inward persisting throughout the event. Temporal association between particle increases and small brightness surges in the extreme-ultraviolet observed by the Solar TErrestrial RElations Observatory, which were also accompanied by type III radio emission seen by the Electromagnetic Fields Investigation on PSP, indicates that the source of this event was an active region nearly 80 degrees east of the nominal PSP magnetic footpoint. This suggests that the field lines expanded over a wide longitudinal range between the active region in the photosphere and the corona.

[11]  arXiv:1912.03386 [pdf, other]

Title: A Geometric Probe of Cosmology: I. Gravitational Lensing Time Delays and Quasar Reverberation Mapping

Authors: Angela L.H. Ng, Geraint F. Lewis

Comments: 8 pages, 6 figures, Accepted MNRAS

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

We present a novel, purely geometric probe of cosmology based on measurements of differential time delays between images of strongly lensed quasars due to finite source effects. Our approach is solely dependent on cosmology via a ratio of angular diameter distances, the image separation, and the source size. It thereby entirely avoids the challenges of lens modelling that conventionally limit time delay cosmography, and instead entails the lensed reverberation mapping of the quasar Broad Line Region. We demonstrate that differential time delays are measurable with short cadence spectroscopic monitoring of lensed quasars, through the timing of kinematically identified features within the broad emission lines. This provides a geometric determination of an angular diameter distance ratio complementary to standard probes, and as a result is a potentially powerful new method of constraining cosmology.

[12]  arXiv:1912.03392 [pdf, other]

Title: Iterative removal of redshift space distortions from galaxy clustering

Authors: Yuchan Wang (Durham), Baojiu Li (ICC, Durham), Marius Cautun (Leiden)

Comments: 21 pages, 12 figures, 1 table; submitted to MNRAS; comments welcome

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

Observations of galaxy clustering are made in redshift space, which results in distortions to the underlying isotropic distribution of galaxies. These redshift-space distortions (RSD) not only degrade important features of the matter density field, such as the baryonic acoustic oscillation (BAO) peaks, but also pose challenges for the theoretical modelling of observational probes. Here we introduce an iterative nonlinear reconstruction algorithm to remove RSD effects from galaxy clustering measurements, and assess its performance by using mock galaxy catalogues. The new method is found to be able to recover the real-space galaxy correlation function, and reduce the quadrupole moment to zero, with a $\sim1\%$ accuracy, on scales $s\gtrsim15$-$20h^{-1}{\rm Mpc}$. It also leads to an improvement in the reconstruction of the initial density field, which could help to accurately locate the BAO peaks. An `internal calibration' scheme is proposed to determine the values of cosmological parameters as a part of the reconstruction process, and possibilities to break parameter degeneracies are discussed. RSD reconstruction can offer a potential way to simultaneously extract the cosmological parameters, initial density field, real-space galaxy positions and large-scale peculiar velocity field (of the real Universe), making it an alternative to standard perturbative approaches in galaxy clustering analysis, bypassing the need for RSD modelling.

[13]  arXiv:1912.03414 [pdf, other]

Title: Hot Gas Flows on Parsec Scale in the Low-Luminosity Active Galactic Nucleus NGC 3115

Authors: Zhiyuan Yao, Zhaoming Gan

Comments: 13 pages, 8 figures. Accepted for publication by MNRAS

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

NGC 3115 is known as the low-luminosity active galactic nucleus which hosts the nearest ($z\sim0.002$) billion solar mass supermassive black hole ($\sim1.5\times10^9~M_\odot$). Its Bondi radius $r_\mathrm{B}$ ($\sim3\farcs6$) can be readily resolved with Chandra, which offers us an excellent opportunity to investigate the accretion flow onto a supermassive black hole. In this paper, we perform two-dimensional hydrodynamical numerical simulations, tailored for NGC 3115, on the mass flow across the Bondi radius. Our best fittings for the density and temperature agree well with the observations of the hot interstellar medium in the centre of NGC 3115. We find that the flow properties are solely determined by the local galaxy properties in the galaxy centre: (1) stellar winds (including supernova ejecta) supply the mass and energy sources for the accreting gas; (2) similar to the one-dimensional calculations, a stagnation radius $r_\mathrm{st}\sim0.1~r_\mathrm{B}$ is also found in the two-dimensional simulations, which divides the mass flow into an inflow-outflow structure; (3) the radiatively inefficient accretion flow theory applies well inside the stagnation radius, where the gravity is dominated by the supermassive black hole and the gas is supported by rotation; (4) beyond the stagnation radius, the stellar gravity dominates the spherical-like fluid dynamics and causes the transition from a steep density profile outside to a flat density profile inside the Bondi radius.

[14]  arXiv:1912.03428 [pdf, other]

Title: The host galaxies of z=7 quasars: predictions from the BlueTides simulation

Authors: Madeline A. Marshall, Yueying Ni, Tiziana Di Matteo, J. Stuart B. Wyithe, Stephen Wilkins, Rupert A.C. Croft

Comments: 15 pages, 18 figures. Submitted to MNRAS

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

We examine the properties of the host galaxies of $z=7$ quasars using the large volume, cosmological hydrodynamical simulation BlueTides. We find that the most massive black holes and quasars are hosted by massive galaxies with stellar masses $\log(M_\ast/M_\odot)=10.8\pm0.2$, and $10.2\pm0.4$, which have a wide range of star formation rates, of $50\substack{+119 \\ -35}M_\odot/\rm{yr}$ and $19\substack{+28 \\ -12}M_\odot/\rm{yr}$, respectively. The hosts of the most massive black holes and quasars in BlueTides are generally bulge-dominated, with bulge-to-total mass ratio $B/T\simeq0.85\pm0.1$, however their morphologies are not biased relative to the overall $z=7$ galaxy sample. We find that the hosts of the most massive black holes and quasars are significantly more compact, with half-mass radii $R_{0.5}=0.29\substack{+0.15 \\ -0.10}$ kpc and $0.28\substack{+0.08 \\ -0.06}$ kpc respectively, relative to galaxies with similar masses, which have $R_{0.5}=0.5\substack{+0.3 \\ -0.2}$ kpc. We make mock James Webb Space Telescope (JWST) images of these quasars and their host galaxies. We find that distinguishing the host from the quasar emission will be possible but still challenging with JWST, due to the small sizes of quasar hosts. We find that currently observable quasar samples are biased tracers of the intrinsic black hole--stellar mass relations, following a relation that is 0.27 dex higher than that of the full galaxy sample. Finally, we find that black hole hosts are generally quite isolated. However, the most massive black holes are more likely to be found in denser environments than the typical $M_{\textrm{BH}}>10^{6.5}M_\odot$ black hole, indicating that minor mergers at least play some role in growing black holes in the early Universe.

[15]  arXiv:1912.03466 [pdf, ps, other]

Title: The Possible Electromagnetic Counterparts of the First High-Probability NSBH Merger LIGO/Virgo S190814bv

Authors: Hao Wei, Minzi Feng

Comments: 11 pages, 1 figure, 3 tables, revtex4

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

LIGO/Virgo S190814bv is the first high-probability neutron star - black hole (NSBH) merger candidate, whose gravitational waves (GWs) triggered LIGO/Virgo detectors at 21:10:39.012957 UT, 14 August 2019. It has a probability $>99\%$ of being a NSBH merger, with a low false alarm rate (FAR) of 1 per 1.559e+25 years. For a NSBH merger, electromagnetic counterparts (especially short gamma-ray bursts (GRBs)) are generally expected. However, no electromagnetic counterpart has been found in the extensive follow-up observing campaign. In the present work, we propose a novel explanation to this null result, and find 9 short GRBs as the possible electromagnetic counterparts associated with the real NSBH merger corresponding to LIGO/Virgo S190814bv.

[16]  arXiv:1912.03480 [pdf, other]

Title: Observations of solar chromospheric oscillations at 3 mm with ALMA

Authors: S. Patsourakos, C. E. Alissandrakis, A. Nindos, T. S. Bastian

Comments: A&A, accepted for publication (abbreviated abstract)

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

We studied chromospheric oscillations using Atacama Large millimeter and sub-millimeter Array (ALMA) time-series of interferometric observations of the quiet Sun obtained at 3 mm with a 2-s cadence and a spatial resolution of a few arcsec. The same analysis, over the same fields of view and for the same intervals, was performed for simultaneous Atmospheric Imaging Assembly (AIA) image sequences in 1600 A. Spatially-resolved chromospheric oscillations at 3 mm, with frequencies of $ 4.2 +- 1.7$ mHz are observed in the quiet Sun, in both cell and network. The coherence length-scale of the oscillations is commensurate with the spatial resolution of our ALMA observations. Brightness-temperature fluctuations in individual pixels could reach up to a few hundred K, while the spatially averaged power spectral densities yield rms in the range ~ 55-75 K, i.e., up to ~ 1 % of the averaged brightness temperatures and exhibit a moderate increase towards the limb. For AIA 1600 A, the oscillation frequency is 3.7 +- 1.7 mHz. The relative rms is up to 6 % of the background intensity, with a weak increase towards disk center (cell, average). ALMA 3 mm time-series lag AIA 1600 A by ~ 100 s, which corresponds to a formation-height difference of ~ 1200 km. The ALMA oscillations that we detected exhibit higher amplitudes than those derived from the lower (~ 10 arcsec) resolution observations at 3.5 mm by White et al. (2006). Chromospheric oscillations are, therefore, not fully resolved at the length-scale of the chromospheric network, and possibly not even at the spatial resolution of our ALMA observations. Any study of transient brightenings in the mm-domain should take into account the oscillations.

[17]  arXiv:1912.03494 [pdf, other]

Title: An Observationally Constrained Analytical Model for Predicting the Magnetic Field Vectors of ICMEs at 1 AU

Authors: Ranadeep Sarkar, Nat Gopalswamy, Nandita Srivastava

Comments: 16 pages, 10 figures, Accepted for publication in the Astrophysical Journal

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

We report on an observationally constrained analytical model, the INterplanetary Flux ROpe Simulator (INFROS), for predicting the magnetic-field vectors of coronal mass ejections (CMEs) in the interplanetary medium. The main architecture of INFROS involves using the near-Sun flux rope properties obtained from the observational parameters that are evolved through the model in order to estimate the magnetic field vectors of interplanetary CMEs (ICMEs) at any heliocentric distance. We have formulated a new approach in INFROS to incorporate the expanding nature and the time-varying axial magnetic field-strength of the flux rope during its passage over the spacecraft. As a proof of concept, we present the case study of an Earth-impacting CME which occurred on 2013 April 11. Using the near-Sun properties of the CME flux rope, we have estimated the magnetic vectors of the ICME as intersected by the spacecraft at 1 AU. The predicted magnetic field profiles of the ICME show good agreement with those observed by the in-situ spacecraft. Importantly, the maximum strength (10.5 $\pm$ 2.5 nT) of the southward component of the magnetic field (Bz) obtained from the model prediction, is in agreement with the observed value (11 nT). Although our model does not include the prediction of the ICME plasma parameters, as a first order approximation it shows promising results in forecasting of Bz in near real time which is critical for predicting the severity of the associated geomagnetic storms. This could prove to be a simple space-weather forecasting tool compared to the time-consuming and computationally expensive MHD models.

[18]  arXiv:1912.03503 [pdf, other]

Title: Future stellar flybys of the Voyager and Pioneer spacecraft

Authors: Coryn A.L. Bailer-Jones (MPIA Heidelberg), Davide Farnocchia (JPL Pasadena)

Comments: Extended version of our article published on 3 April 2019 in RNAAS

Journal-ref: Research Notes of the American Astronomical Society, 3, 59 (2019)

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

The Pioneer 10 and 11 and Voyager 1 and 2 spacecraft, launched in the 1970s, are heading out of the solar system. Using the astrometric and radial velocity data from the second Gaia data release, we integrate the trajectories of 7.4 million stars, and the spacecraft, through a Galactic potential in order to identify those stars the spacecraft will pass closest to. The closest encounters for all spacecraft take place at separations between 0.2 and 0.5 pc within the next million years. The closest encounter will be by Pioneer 10 with the K8 dwarf HIP 117795, at 0.23 pc in 90 kyr at a high relative velocity of 291 km/s.

[19]  arXiv:1912.03530 [pdf, other]

Title: Optical variability modeling of newly identified blazar candidates behind Magellanic Clouds

Authors: Natalia Żywucka, Mariusz Tarnopolski, Markus Böttcher, Łukasz Stawarz, Volodymyr Marchenko

Comments: Accepted for publication in ApJ

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

We present an optical variability study of 44 newly identified blazar candidates behind the Magellanic Clouds, including 27 flat spectrum radio quasars (FSRQs) and 17 BL Lacertae objects (BL Lacs). All objects in the sample possess high photometric accuracy and irregularly sampled optical light curves (LCs) in I filter from the long-term monitoring conducted by the Optical Gravitational Lensing Experiment. We investigated the variability properties to look for blazar-like characteristics and to analyze the long-term behaviour. We analyzed the LCs with the Lomb-Scargle periodogram to construct power spectral densities (PSDs), found breaks for several objects, and linked them with accretion disk properties. In this way we constrained the black hole (BH) masses of 18 FSRQs to lie within the range $8.18\leq\log (M_{\rm BH}/M_\odot)\leq 10.84$, assuming a wide range of possible BH spins. By estimating the bolometric luminosities, we applied the fundamental plane of active galactic nuclei variability as an independent estimate, resulting in $8.4\leq\log (M_{\rm BH}/M_\odot)\leq 9.6$, with a mean error of 0.3. Many of the objects have very steep PSDs, with high frequency spectral index in the range $3-7$. An alternative attempt to classify the LCs was made using the Hurst exponent, $H$, and the $\mathcal{A}-\mathcal{T}$ plane. Two FSRQs and four BL Lacs yielded $H>0.5$, indicating presence of long-term memory in the underlying process governing the variability. Additionally, two FSRQs with exceptional PSDs, stand out also in the $\mathcal{A}-\mathcal{T}$ plane.

[20]  arXiv:1912.03543 [pdf, other]

Title: On the nature of supersonic turbulence in Giant HII Regions

Authors: Jorge Melnick (1,4), Roberto Terlevich (2,3), Guillermo Tenorio-Tagle (2), Eduardo Telles (4), Elena Terlevich (2) ((1) European Southern Observatory, (2) Instituto Nacional de Astrofisica Optica y Electronica, Puebla, Mexico, (3) Institute of Astronomy, University of Cambridge, UK, (4) Observatorio Nacional, Rio de Janeiro, Brasil)

Comments: 9 pages, 11 figures, submitted for publication in A&A

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

New FLAMES/GIRAFFE public data allows to revisit the issue of the origin of the supersonic turbulence inferred in the ionized gas of Giant HII Regions using the prototypical 30~Doradus nebula in the LMC as a guide. We find that the velocity width of the integrated H$\alpha$ line-profile of 30~Doradus can only be explained by the motion of macroscopic parcels of gas driven by the gravitational potential of the stars and gas with a significant contribution of stellar winds. At all positions within the nebula we find that an additional very broad ($\sigma=40-50$~\kms) unresolved component is required to fit the extended wings of the profiles. We find that fitting two Gaussian components to the integrated emission-line profiles provides a robust way of separating the contributions of stellar winds and gravity. Assuming an effective radius of 10pc for the nebula we thus infer a dynamical mass of $\sim10^6$~\msun~ for 30Dor. Our analysis of published observations of the second largest Giant HII Region in the Local Group, NGC~604, shows that our results for 30~Doradus apply to GHR as a class.

[21]  arXiv:1912.03547 [pdf, other]

Title: Detection and Characterisation of Cosmic Rays in AstroSat-CZT Imager data

Authors: Debdutta Paul

Comments: 23 pages, 16 figures

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

The Cadmium Zinc Telluride (CZT) Imager on-board AstroSat, consists of pixelated CZT detectors, which are triggered by individual photons bombarding them, and records each such trigger separately as an individual 'event' with information about its time, detector co-ordinates, and channel, which scales with the energy of the photon. This makes it prone to detect not only photons from astrophysical sources of interest, but also to a number of other events. Preliminary analysis of the CZTI data already revealed the presence of cosmic rays. In this work, it is shown that in addition, it is also bombarded with higher energy cosmic rays, which produce signatures previously seen in the PICsIT detector on-board INTEGRAL. An algorithm to automatically detect them is presented. It is optimized to not eliminate known 'double-events', which are astrophysical produced photons and their Compton-scattered counterparts used for measuring polarization of astrophysical sources. The robustness of the algorithm is highlighted by using examples of Gamma Ray Bursts as target sources. The importance of using such an algorithm is highlighted for the detection of short Gamma Ray Bursts.

[22]  arXiv:1912.03599 [pdf, other]

Title: Weighing in on black hole binaries with BPASS: LB-1 does not contain a 70M$_{\odot}$ black hole

Authors: J.J. Eldridge, E.R. Stanway, K. Breivik, A.R. Casey, D.T.H. Steeghs, H. F. Stevance

Comments: Submitted to MNRAS, 8 pages, 5 figures, 1 table

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

The recent identification of a candidate very massive 70 M(Sun) black hole is at odds with our current understanding of stellar winds and pair-instability supernovae. We investigate alternate explanations for this system by searching the BPASS v2.2 stellar and population synthesis models for those that match the observed properties of the system. We find binary evolution models that match the LB-1 system, at the reported Gaia distance, with more moderate black hole masses of 4 to 7 M(Sun). We also examine the suggestion that the binary motion may have led to an incorrect distance determination by Gaia. We find that the Gaia distance is accurate and that the binary system is consistent with the observation at this distance. Consequently it is highly improbable that the black hole in this system has the extreme mass originally suggested. Instead, it is more likely to be representative of the typical black hole binary population expected in our Galaxy.

[23]  arXiv:1912.03633 [pdf, other]

Title: The Activation of Galactic Nuclei and Their Accretion Rates are Linked to the Star Formation Rates and Bulge-types of Their Host Galaxies

Authors: Hassen M. Yesuf, S. M. Faber, David C. Koo, Joanna Woo, Joel R. Primack, Yifei Luo

Comments: 22 pages, 14 figures, accepted by ApJ

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

We use bulge-type classifications of 809 representative SDSS galaxies by Gadotti (2009) to classify a large sample of galaxies into real bulges (classical or elliptical) and pseudobulges using Random Forest. We use structural and stellar population predictors that can easily be measured without image decomposition. Multiple parameters such as the central mass density with 1 kpc, concentration index, S\'{e}rsic index and velocity dispersion do result in accurate bulge classifications when combined together. We classify $\sim 44,500$ face-on galaxies above stellar mass of 10$^{10}$ M$_\odot$ and redshift $ 0.02 < z < 0.07$ into real bulges or pseudobulges with $93 \pm 2$\% accuracy. We show that $\sim 75 - 90\%$ of AGNs identified by the optical line ratio diagnostic are hosted by real bulges. The pseudobulge fraction significantly decreases with AGN signature as the line ratios change from indicating pure star formation ($\sim 54 \pm 4$ \%), to composite of star formation and AGN ($\sim 18 \pm 3$\%), and to AGN-dominated galaxies ($\sim 5 \pm 3$\%). Using the dust-corrected [\ion{O}{3}] luminosity as an AGN accretion indicator, and the stellar mass and radius as proxies for a black hole mass, we find that AGNs in real bulges have lower Eddington ratios than AGNs in pseudobulges. Real bulges have a wide range of AGN and star formation activities, although most of them are weak AGNs. For both bulge-types, their Eddington ratios are correlated with specific star formation rates (SSFR). Real bulges have lower specific accretion rate but higher AGN fraction than pseudobulges do at similar SSFRs.

[24]  arXiv:1912.03638 [pdf, ps, other]

Title: Magnetic activity and evolution of the four Hyades K giants

Authors: Klaus-Peter Schröder, Marco Mittag, Dennis Jack, Abigali Rodriguez Jimenez, Jürgen H.M.M. Schmitt

Comments: 11 pages with 7 Figs

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

We determine the exact physical parameters of the four Hyades cluster K giants, using their parallaxes and atmospheric modeling of our red-channel TIGRE high-resolution spectra. Performing a comparison with well-tested evolutionary tracks, we derive exact masses and evolutionary stages. At an age of 588 ($\pm 60$) Myrs and with a metallicity of Z=0.03 (consistent with the spectroscopic abundances), we find HD~27371 and HD~28307, the two less bright K giants, at the onset of central helium-burning, entering their blue loops with a mass of 2.62 $M_{\odot}$, while the slightly brighter stars HD~28305 and HD~27697 are already exiting their blue loop. Their more advanced evolution suggests a higher mass of 2.75 $M_{\odot}$.
Notably, this pairing coincides with the different activity levels, which we find for these four stars from chromospheric activity monitoring with TIGRE and archival Mount Wilson data as well as from ROSAT coronal detections: The two less evolved K giants are the far more active pair, and we confidently confirm their rotation with periods of about 142 days. This work therefore provides some first, direct evidence of magnetic braking during the 130~Myrs lasting phase of central helium-burning, similar to what has long been known to occur to cool main-sequence stars.

[25]  arXiv:1912.03640 [pdf, ps, other]

Title: A possible radio signal of annihilating dark matter in the Abell 4038 cluster

Authors: Man Ho Chan, Chak Man Lee

Comments: Accepted for publication in MNRAS Letters

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

In the past decade, some telescopes (e.g. Fermi-LAT, AMS and DAMPE) were launched to detect the signals of annihilating dark matter in our Galaxy. Although some excess of gamma rays, anti-protons and electrons/positrons have been reported and claimed as dark matter signals, the uncertainties of Galactic pulsars' contributions are still too large to confirm the claims. In this letter, we report a possible radio signal of annihilating dark matter manifested in the archival radio continuum spectral data of the Abell 4038 cluster. By assuming the thermal annihilation cross section and comparing the dark matter annihilation model with the null hypothesis (cosmic ray emission without dark matter annihilation), we get very large Test Statistic values TS $>45$ for four popular annihilation channels, which correspond to more than $6.5 \sigma$ statistical preference. This provides a very strong evidence for the existence of annihilating dark matter. In particular, our results also support the recent claims of dark matter mass $m \approx 30-50$ GeV annihilating via the $b\bar{b}$ quark channel with the thermal annihilation cross section.

[26]  arXiv:1912.03664 [pdf, ps, other]

Title: Investigation of near-contact semi-detached binary W UMi through observations and evolutionary models

Authors: Faruk Soydugan, Esin Soydugan, Fahri Aliçavuş (Çanakkale Onsekiz Mart University, Department of Physics, Turkey)

Comments: Accepted for publication in Research in Astronomy and Astrophysics (RAA). 16 pages, 7 figures

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

W UMi is a near contact, semi-detached, double-lined eclipsing binary star with an orbital period of 1.7 days. Simultaneous analysis of new BVR multi-color light curves and radial velocity data yields the main astrophysical parameters of the binary and its component stars. We determined mass and radius to be M$_{1}$=3.22$\pm$0.08 M$_{\odot}$, R$_{1}$=3.63$\pm$0.04 R$_{\odot}$ for the primary star and M$_{2}$=1.44$\pm$0.05 M$_{\odot}$, R$_{2}$=3.09$\pm$0.03 R$_{\odot}$ for the secondary star. Based on analysis of mid-eclipse times, variation in the orbital period is represented by a cyclic term and a downward parabola. Mass loss from the system is suggested for a secular decrease (-0.02 s yr$^{-1}$) in the period. Both the mechanisms of a hypothetical tertiary star orbiting around W UMi and the surface magnetic activity of the less massive cooler companion were used to interpret periodic changes. Observational parameters were found to be consistent with binary stellar evolution models produced in the non-conservative approach of MESA at a higher metallicity than the Sun and an age of about 400 Myr for the system. Evidence that the system is rich in metal was obtained from spectral and kinematic analysis as well as evolution models. W UMi, a high mass ratio system compared to classical semi-detached binaries, is an important example since it is estimated from binary evolutionary models that the system may reach its contact phase in a short time interval.

[27]  arXiv:1912.03666 [pdf, other]

Title: Neutrinos from blazars

Authors: Matteo Cerruti

Comments: 8 pages; invited plenary contribution to appear in the proceedings of the TAUP 2019 conference (Toyama, September 9-13, 2019)

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

The evidence for joint gamma and neutrino emission from the blazar TXS 0506+056 has renewed interest in blazars as neutrino sources. The detection of neutrinos from blazars can be seen as the smoking gun for the presence of relativistic protons in blazar's jets, and can thus help identify blazars, and active galactic nuclei in general, as cosmic-ray accelerators. In this contribution I first introduce blazars and blazar hadronic models, and then present the results of the multi-messenger modeling of both the 2017 gamma-neutrino flare, and the 2014-2015 neutrino-only flare of TXS 0506+056. For the first time it is possible to constrain blazar hadronic models using the information from neutrino detectors, and I discuss the implications of these neutrino observations on our understanding of the physics of relativistic jets from super-massive black-holes.

[28]  arXiv:1912.03669 [pdf, other]

Title: SCUBA-2 Ultra Deep Imaging Eao Survey (Studies) III: Multi-wavelength properties, luminosity functions and preliminary source catalog of 450-$μ$m-selected galaxies

Authors: Chen-Fatt Lim, Wei-Hao Wang, Ian Smail, Douglas Scott, Chian-Chou Chen, Yu-Yen Chang, James M. Simpson, Yoshiki Toba, Xinwen Shu, Dave Clements, Josh Greenslade, YiPing Ao, Arif Babul, Jack Birkin, Scott C. Chapman, Tai-An Cheng, Brian S. Cho, Helmut Dannerbauer, Ugnė Dudzevičiūtė, James Dunlop, Yu Gao, Tomotsugu Goto, Luis C. Ho, Li-Ting Hsu, Ho Seong Hwang, Woong-Seob Jeong, Maciej Koprowski, Chien-Hsiu Lee, Ming-Yi Lin, Wei-Ching Lin, Michał J. Michałowski, Harriet Parsons, Marcin Sawicki, Raphael Shirley, Hyunjin Shim, Sheona Urquhart, Jianfa Wang, Tao Wang

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

We construct a SCUBA-2 450-$\mu$m map in the COSMOS field that covers an area of 300 arcmin$^{2}$ and reaches a 1$\sigma$ noise level of 0.65 mJy in the deepest region. We extract 256 sources detected at 450 $\mu$m with signal-to-noise ratio $>$ 4.0 and analyze the physical properties of their multi-wavelength counterparts. We find that most of the sources are at $z\lesssim3$, with a median of $z = 1.79^{+0.03}_{-0.15}$. About $35^{+32}_{-25}$% of our sources are classified as starburst galaxies based on their total star-formation rates (SFRs) and stellar masses ($M_{\ast}$). By fitting the far-infrared spectral energy distributions, we find that our 450-$\mu$m-selected sample has a wide range of dust temperatures (20 K $ \lesssim T_{\rm d} \lesssim$ 60 K), with a median of ${T}_{\rm d} = 38.3^{+0.4}_{-0.9}$ K. We do not find a redshift evolution in dust temperature for sources with $L_{\rm IR}$ > $10^{12}$ $\rm L_\odot$ at $z<3$. However, we find a moderate correlation where dust temperature increases with the deviation from the SFR-$M_{\ast}$ relation. The increase in dust temperature also correlates with optical morphology, which is consistent with merger-triggered starbursts in sub-millimeter galaxies. Our galaxies do not show the tight IRX-$\beta_{\rm UV}$ correlation that has been observed in the local Universe. We construct the infrared luminosity functions of our 450-$\mu$m sources and measure their comoving SFR densities. The contribution of the $L_{\rm IR}$ > $10^{12}$ $\rm L_\odot$ population to the SFR density rises dramatically from $z$ = 0 to 2 ($\propto$ ($1+z$)$^{3.9\pm1.1}$) and dominates the total SFR density at $z \gtrsim 2$.

[29]  arXiv:1912.03683 [pdf, other]

Title: The colors and sizes of recently quenched galaxies: a result of compact starburst before quenching

Authors: Po-Feng Wu, Arjen van der Wel, Rachel Bezanson, Anna Gallazzi, Camilla Pacifici, Caroline M. S. Straatman, Ivana Barisic, Eric F. Bell, Priscilla Chauke, Francesco D'Eugenio, Marijn Franx, Adam Muzzin, David Sobral, Josha van Houdt

Comments: 16 pages, 8 figures, 1 table, accepted by ApJ

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

We analyze the colors and sizes of 32 quiescent (UVJ-selected) galaxies with strong Balmer absorption ($\mbox{EW}(H\delta) \geq 4$\AA) at $z\sim0.8$ drawn from DR2 of the LEGA-C survey to test the hypothesis that these galaxies experienced compact, central starbursts before quenching. These recently quenched galaxies, usually referred to as post-starburst galaxies, span a wide range of colors and we find a clear correlation between color and half-light radius, such that bluer galaxies are smaller. We build simple toy models to explain this correlation: a normal star-forming disk plus a central, compact starburst component. Bursts with exponential decay timescale of $\sim$~100 Myr that produce $\sim10\%$ to more than 100\% of the pre-existing masses can reproduce the observed correlation. More significant bursts also produce bluer and smaller descendants. Our findings imply that when galaxies shut down star formation rapidly, they generally had experienced compact, starburst events and that the large, observed spread in sizes and colors mostly reflects a variety of burst strengths. Recently quenched galaxies should have younger stellar ages in the centers; multi-wavelength data with high spatial resolution are required to reveal the age gradient. Highly dissipative processes should be responsible for this type of formation history. While determining the mechanisms for individual galaxies is challenging, some recently quenched galaxies show signs of gravitational interactions, suggesting that mergers are likely an important mechanism in triggering the rapid shut-down of star-formation activities at $z\sim0.8$.

[30]  arXiv:1912.03687 [pdf, ps, other]

Title: The Cosmological Parameters (2019)

Authors: Ofer Lahav, Andrew R Liddle

Comments: 21 pages TeX file with two figures. Article for The Review of Particle Physics 2020 (aka the Particle Data Book), on-line version at this http URL . This article supersedes arXiv:1401.1389, arXiv:1002.3488, arXiv:astro-ph/0601168, arXiv:astro-ph/0406681

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

This is a review article for The Review of Particle Physics 2020 (aka the Particle Data Book). It forms a compact review of knowledge of the cosmological parameters at the end of 2019. Topics included are Parametrizing the Universe; Extensions to the standard model; Probes; Bringing observations together; Outlook for the future.

[31]  arXiv:1912.03721 [pdf, other]

Title: Tracing shock type with chemical diagnostics: an application to L1157

Authors: Tomas James, Serena Viti, Jonathan Holdship, Izaskun Jimenez-Serra

Comments: Submitted to, and accepted by, A&A

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

Aims: The physical structure of a shock wave may take a form unique to its shock type, implying that the chemistry of each shock type is unique as well. We aim to investigate the different chemistries of J-type and C-type shocks in order to identify unique molecular tracers of both shock types. We apply these diagnostics to the protostellar outflow L1157 to establish whether the B2 clump could host shocks exhibiting type-specific behaviour. Of particular interest is the L1157-B2 clump, which has been shown to exhibit bright emission in S-bearing species and HNCO.
Methods: We simulate, using a parameterised approach, a planar, steady-state J-type shock wave using UCLCHEM. We compute a grid of models using both C-type and J-type shock models to determine the chemical abundance of shock-tracing species as a function of distance through the shock and apply it to the L1157 outflow. We focus on known shock-tracing molecules such as H2O, HCN, and CH3 OH.
Results: We find that a range of molecules including H2O and HCN have unique behaviour specific to a J-type shock, but that such differences in behaviour are only evident at low $v_{s}$ and low $n_{H}$. We find that CH3OH is enhanced by shocks and is a reliable probe of the pre-shock gas density. However, we find no difference between its gas-phase abundance in C-type and J-type shocks. Finally, from our application to L1157, we find that the fractional abundances within the B2 region are consistent with both C-type and J-type shock emission.

[32]  arXiv:1912.03731 [pdf, ps, other]

Title: On the thermal effects on radio waves propagating in the pulsar magnetosphere

Authors: A.G.Mikhaylenko, V.S.Beskin, Ya.N.Istomin

Comments: 18 pages, 11 figures, will be submitted to Journal of Plasma Physics

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

Thermal effects on the properties of four electromagnetic waves propagating in the pulsar magnetosphere are analyzed. It is shown that thermal effects change only quantitatively the dispersion properties of superluminal ordinary O-mode freely escaping the pulsar magnetosphere; properties of the extraordinary X-mode remain unchanged. As for two subluminal waves propagating along magnetic field lines, for them thermal effects result in essential absorption. However, this attenuation occurs at considerable distances from the neutron star, so there is no doubt in their existence.

[33]  arXiv:1912.03736 [pdf, other]

Title: The circumstellar environment of 55 Cnc: The super-Earth 55 Cnc e as a primary target for star-planet interactions

Authors: C. P. Folsom, D. Ó Fionnagáin, L. Fossati, A. A. Vidotto, C. Moutou, P. Petit, D. Dragomir, J.-F. Donati

Comments: Accepted for publication in A&A, 6 pages, 5 figures

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

Context. 55 Cancri hosts five known exoplanets, most notably the hot super-Earth 55 Cnc e, which is one of the hottest known transiting super-Earths. Aims. Due to the short orbital separation and host star brightness, 55 Cnc e provides one of the best opportunities for studying star-planet interactions (SPIs). We aim to understand possible SPIs in this system, which requires a detailed understanding of the stellar magnetic field and wind impinging on the planet. Methods. Using spectropolarimetric observations, and Zeeman Doppler Imaging, we derive a map of the large-scale stellar magnetic field. We then simulate the stellar wind starting from the magnetic field map, using a 3D MHD model. Results. The map of the large-scale stellar magnetic field we derive has an average strength of 3.4 G. The field has a mostly dipolar geometry, with the dipole tilted by 90 degrees with respect to the rotation axis, and dipolar strength of 5.8 G at the magnetic pole. The wind simulations based on this magnetic geometry lead us to conclude that 55 Cnc e orbits inside the Alfv\'en surface of the stellar wind, implying that effects from the planet on the wind can propagate back to the stellar surface and result in SPI.

[34]  arXiv:1912.03742 [pdf, other]

Title: The vertical Na-O relation in the bulge globular cluster NGC 6553

Authors: C. Muñoz, S. Villanova, D. Geisler, C.C. Cortés, C. Moni Bidin, R.E. Cohen, I. Saviane, B. Dias, B. Tang, F. Mauro

Comments: 12 pages, 11 figures, 4 tables. Submitted to MNRAS

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

In this article, we present a detailed chemical analysis of seven red giant members of NGC 6553 using high-resolution spectroscopy from VLT FLAMES. We obtained the stellar parameters (Teff, Log(g), vt, [Fe/H]) of these stars from the spectra, and we measured the chemical abundance for 20 elements, including light elements, iron-peak elements, alpha-elements and neutron-capture elements. The metallicities in our sample stars are consistent with a homogeneous distribution. We found a mean of [Fe/H]=-0.14+/-0.07 dex, in agreement with other studies. Using the alpha-elements Mg, Si, Ca and Ti we obtain the mean of [alpha/Fe]=0.11+/-0.05. We found a vertical relation between Na and O, characterized by a significant spread in Na and an almost non-existent spread in O. In fact, Na and Al are the only two light elements with a large intrinsic spread, which demonstrates the presence of Multiple Populations (MPs). An intrinsic spread in Mg is not detected in this study. The alpha, iron-peak and neutron capture elements show good agreement with the trend of the bulge field stars, indicating similar origin and evolution, in concordance with our previous studies for two other bulge GCs (NGC 6440 and NGC 6528).

[35]  arXiv:1912.03753 [pdf, ps, other]

Title: V346 Nor: the post-outburst life of a peculiar young eruptive star

Authors: Á. Kóspál, Zs. M. Szabó, P. Ábrahám, S. Kraus, M. Takami, P. W. Lucas, C. Contreras Peña, A. Udalski

Comments: 22 pages, 11 figures, 2 tables, accepted for publication in the Astrophysical Journal

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

FU Orionis-type objects (FUors) are young low-mass stars undergoing powerful accretion outbursts. The increased accretion is often accompanied by collimated jets and energetic, large-scale molecular outflows. The extra heating during the outburst may also induce detectable geometrical, chemical, and mineralogical changes in the circumstellar material, affecting possible planet formation around these objects. V346 Nor is a southern FUor with peculiar spectral characteristics. Decades after the beginning of its outburst, it unexpectedly underwent a fading event around 2010 due to a decrease in the mass accretion rate onto the star by at least two orders of magnitude. Here we present optical and near-infrared photometry and spectroscopy obtained after the minimum. Our light curves show a gradual re-brightening of V346 Nor, with its Ks-band brightness only 1.5 mag below the outburst brightness level. Our VLT/XSHOOTER spectroscopic observations display several strong forbidden emission lines towards the source from various metals and molecular hydrogen, suggesting the launch of a new jet. Our N-band spectrum obtained with VLT/VISIR outlines a deeper silicate absorption feature than before, indicating that the geometry of the circumstellar medium has changed in the post-outburst period compared to peak brightness.

[36]  arXiv:1912.03777 [pdf, other]

Title: The role of Alfvén wave dynamics on the large scale properties of the solar wind: comparing a MHD simulation with PSP E1 data

Authors: Victor Réville, Marco Velli, Olga Panasenco, Anna Tenerani, Chen Shi, Samuel T. Badman, Stuart D. Bale, J. C. Kasper, Michael L. Stevens, Kelly E. Korreck, J. W. Bonnell, Anthony W. Case, Thierry Dudok de Wit, Keith Goetz, Peter R. Harvey, Davin E. Larson, Roberto Livi, David M. Malaspina, Robert J. MacDowall, Marc Pulupa, Phyllis L. Whittlesey

Comments: 13 pages, 7 figures, to appear in the Parker Solar Probe ApJ Special Issue

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

During Parker Solar Probe's first orbit, the solar wind plasma has been observed in situ closer than ever before, the perihelion on November 6th 2018 revealing a flow that is constantly permeated by large amplitude Alfv\'enic fluctuations. These include radial magnetic field reversals, or switchbacks, that seem to be a persistent feature of the young solar wind. The measurements also reveal a very strong, unexpected, azimuthal velocity component. In this work, we numerically model the solar corona during this first encounter, solving the MHD equations and accounting for Alfv\'en wave transport and dissipation. We find that the large scale plasma parameters are well reproduced, allowing the computation of the solar wind sources at Probe with confidence. We try to understand the dynamical nature of the solar wind to explain both the amplitude of the observed radial magnetic field and of the azimuthal velocities.

[37]  arXiv:1912.03778 [pdf, other]

Title: Star-planet interaction through spectral lines

Authors: C. Villarreal D'Angelo, A. A. Vidotto, A. Esquivel, M. A. Sgró, T. Koskinen, L. Fossati

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

The growth of spectroscopic observations of exoplanetary systems allows the possibility of testing theoretical models and studying the interaction that exoplanetary atmospheres have with the wind and the energetic photons from the star. In this work, we present a set of numerical 3D simulations of HD 209458b for which spectral lines observations of their evaporative atmosphere are available. The different simulations aim to reproduce different scenarios for the star-planet interaction. With our models, we reconstruct the Ly$\alpha$ line during transit and compare with observations. The results allow us to analyse the shape of the line profile under these different scenarios and the comparison with the observations suggests that HD209458b may have a magnetic field off less than 1 G. We also explore the behaviour of the magnesium lines for models with and without magnetic fields.

[38]  arXiv:1912.03780 [pdf, other]

Title: QSO obscuration at high redshift ($z \gtrsim 7$): Predictions from the BlueTides simulation

Authors: Yueying Ni, Tiziana Di Matteo, Roberto Gilli, Rupert A.C. Croft, Yu Feng, Colin Norman

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

High-$z$ AGNs hosted in gas rich galaxies are expected to grow through significantly obscured accretion phases. This may limit or bias their observability. In this work, we use \textsc{BlueTides}, a large volume cosmological simulation of galaxy formation to examine quasar obscuration for the highest-redshift ($z \geq 7$) supermassive black holes residing in the center of galaxies. We find that for the bright quasars, most of the high column density gas ($>90\%$) resides in the innermost regions of the host galaxy, (typically within $< 10$ ckpc), while the gas in the outskirts is a minor contributor to the $N_\mathrm H$. The brightest quasars can have large angular variations in galactic obscuration, over 2 orders of magnitude, where the lines of sight with the lowest obscuration are those formed via strong gas outflows driven by AGN feedback. We find that for the overall AGN population, the mean $N_\mathrm H$ is generally larger for high luminosity and BH mass, while the $N_\mathrm H$ distribution is significantly broadened, developing a low $N_\mathrm H $ wing due to the angular variations driven by the AGN outflows/feedback. The obscured fraction P($N_{\rm H} > 10^{23} {\rm cm}^{-2}$) typically range from 0.6 to 1.0 for increasing $L_{X}$ (with $L_X > 10^{43} \rm{ergs/s}$), with no clear trend of redshift evolution. With respect to the galaxy host property, we find a linear relation between $N_{\rm H}$, $M_*$ and $M_{\rm H_2}$ with $\log N_{\rm H} = (0.24 \pm 0.03) \log M_{*} + (20.7 \pm 0.3)$ and $\log N_{\rm H} = (0.47 \pm 0.03) \log M_{\rm H_2} + (18.4 \pm 0.3)$. The dust optical depth in the UV band $\tau_{\mathrm UV}$ has tight positive correlation with $N_{\rm H}$. Our dust extincted UVLF is about 1.5 dex lower than the intrinsic UVLF, implying that more than 99\% of the $z \sim 7$ AGNs are heavily dust extincted and therefore would be missed by the UV band observation.

[39]  arXiv:1912.03794 [pdf, other]

Title: The Young Planet DS Tuc Ab has a Low Obliquity

Authors: Benjamin T. Montet, Adina D. Feinstein, Rodrigo Luger, Megan E. Bedell, Michael A. Gully-Santiago, Johanna K. Teske, Sharon Xuesong Wang, R. Paul Butler, Erin Flowers, Stephen A. Shectman, Jeffrey D. Crane, Ian B. Thompson

Comments: 17 pages, four figures, submitted to the AAS Journals

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

The abundance of short-period planetary systems with high obliquities is often taken as evidence that scattering processes play important roles in the formation and evolution of these systems. More recent studies have suggested that wide binary companions can tilt protoplanetary disks, inducing a high obliquity on planets that form through smooth processes like disk migration. DS Tuc Ab, a transiting planet with an an 8.138 day period in the 40 Myr Tucana-Horologium association, likely orbits in the same plane as its now-dissipated protoplanetary disk, enabling us to test these theories of disk physics. Here, we report on Rossiter-McLaughlin observations of one transit of DS Tuc Ab with the Planet Finder Spectrograph on the Magellan Clay Telescope at Las Campanas Observatory. We confirm the previously detected planet by modeling the planet transit and stellar activity signals simultaneously. We test multiple models to describe the stellar activity-induced RV variations over the night of the transit, finding the planet's projected obliquity to be low: $\psi = 12 \pm 13$ degrees, suggesting that this planet likely formed through smooth disk processes and its protoplanetary disk was not significantly torqued by DS Tuc B. This is the youngest planet to be observed using this technique; we provide a discussion on best practices to accurately measure the observed signal of similar young planets.

[40]  arXiv:1912.03803 [pdf, other]

Title: Gamma-ray Burst Afterglows: Time-Varying Extinction, Polarization, and Colors due to Rotational Disruption of Dust Grains

Authors: Thiem Hoang, Nguyen Chau Giang, Le Ngoc Tram

Comments: 19 pages, 16 figures

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

Prompt optical emission of gamma-ray bursts (GRBs) is known to have important effects on the surrounding environment. In this paper, we study rotational disruption and alignment of dust grains by radiative torques (RATs) induced by GRB afterglows and predict their signatures on the observational properties of GRB afterglows. We first study grain disruption using RAdiative Torque Disruption (RATD) mechanism and find that large grains (size $>0.1 \mu\rm m$) within a distance of $d< 40$ pc from the source can be disrupted into smaller grains. We then model the extinction curve of GRB afterglows and find that optical-NIR extinction is rapidly decreased, and UV extinction increases due to the conversion of large grains into smaller ones via RATD. The total-to-selective visual extinction ratio is found to decrease from the standard value of $R_{V}\sim 3.1$ to $\sim 1.5$ after disruption time $t_{\rm disr} \lesssim 10^{4}$ s. Next, we study grain alignment by RATs induced by GRB afterglows and model the wavelength-dependence polarization produced by grains aligned with magnetic fields. We find that polarization degree first increases due to enhanced alignment of small grains and then decreases when grain disruption by RATD begins. The maximum polarization wavelength $ \lambda_{\rm max}$ decreases rapidly from the standard value of $\sim 0.55 \mu\rm m$ to $\sim 0.15 \mu\rm m$ over alignment time of $t_{\rm align} \lesssim 30$ s due to enhanced alignment of small grains. Finally, we found that RATD induces a significant decrease in optical/NIR extinction, producing an optical re-brightening in the observed light curve of GRB afterglows. We show that our theoretical predictions can explain various observational properties of GRB afterglows, including steep extinction curves, time-variability of colors, and optical re-brightening of GRB afterglows.

[41]  arXiv:1912.03822 [pdf, ps, other]

Title: KMT-2019-BLG-0842Lb: A Cold Planet Below the Uranus/Sun Mass Ratio

Authors: Youn Kil Jung, Andrzej Udalski, Weicheng Zang, Ian A. Bond, Jennifer C. Yee, Michael D. Albrow, Sun-Ju Chung, Andrew Gould, Cheongho Han, Kyu-Ha Hwang, Yoon-Hyun Ryu, In-Gu Shin, Yossi Shvartzvald, Sang-Mok Cha, Dong-Jin Kim, Hyoun-Woo Kim, Seung-Lee Kim, Chung-Uk Lee, Dong-Joo Lee, Yongseok Lee, Byeong-Gon Park, Richard W. Pogge, Przemek Mróz, Michał K. Szymański, Jan Skowron, Radek Poleski, Igor Soszyński, Paweł Pietrukowicz, Szymon Kozłowski, Krzysztof Ulaczyk, Krzysztof A. Rybicki, Patryk Iwanek, Marcin Wrona, Fumio Abe, Richard Barry, David P. Bennett, Aparna Bhattacharya, Martin Donachie, Hirosame Fujii, Akihiko Fukui, Yuki Hirao, Yoshitaka Itow, Yukei Kamei, Iona Kondo, Naoki Koshimoto, Man Cheung Alex Li, Yutaka Matsubara, Shota Miyazaki, Yasushi Muraki, et al. (13 additional authors not shown)

Comments: 26 pages, 3 tables, 7 figures, submitted to AAS journal

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

With $q=(4.09\pm 0.27) \times 10^{-5}$, KMT-2019-BLG-0842Lb is the second cold planet with planet-host mass ratio $q$ below that of Uranus relative to the Sun ($q=4.37\times 10^{-5}$), the first having been discovered only in 2018. Hence, such cold, sub-Uranus-ratio planets are probably not rare. We discuss possible improvements in the search for these planets. The Bayesian estimates for the host mass, planet mass, system distance, and planet-host projected separation are $M_{\rm host}=0.76\pm 0.40 M_\odot$, $M_{\rm planet}=10.3\pm 5.5 M_\oplus$, $D_L = 3.3\pm 1.3$ kpc, and $a_\perp = 3.3\pm 1.4$ AU, respectively. The blended light is plausibly due to the host star, an identification that could be tested by high resolution images taken during the next (2020) bulge season.

[42]  arXiv:1912.03839 [pdf, ps, other]

Title: Understanding the coexistence of spin-up and spin-down behaviors in long period X-ray pulsars

Authors: Wei Wang, Hao Tong

Comments: 9 pages, 5 figures, to be published in MNRAS

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

Assuming the wind-fed accretion magnetars in long period X-ray pulsars, we calculated the rotational evolution of the neutron stars. Our calculations considered the effects of the magnetic field decay in magnetars. The results show that wind-fed accretion magnetars can evolve to the long period X-ray pulsars with a spin period much longer than 1000 s. The spin-down trend observed in 4U 2206+54 like sources is expected when the young X-ray binary systems are on the way to their equilibrium period. Detailed calculations showed that its spin-down may be affected by accretion with outflows or accretion while spin-down. Due to the magnetic field decay in magnetars, wind-fed accretion magnetars will have a decreasing equilibrium period for a constant mass accretion rate. For 2S 0114+65, the spin-up rate due to magnetic field decay is one order of magnitude smaller than the observations. The spin-up rate of 2S 0114+65 may be attributed to the formation of a transient disk during wind accretion. The slowest X-ray pulsar AX J1910.7+0917 would be a link source between 4U 2206+54 and 2S 0114+65.

[43]  arXiv:1912.03894 [pdf, other]

Title: Filling the Mass Gap: How Kilonova Observations can Unveil the Nature of the Compact Object Merging with the Neutron Star

Authors: Claudio Barbieri, Om Sharan Salafia, Monica Colpi, Giancarlo Ghirlanda, Albino Perego, Alberto Colombo

Comments: 7 pages, 4 figures. Accepted for publication on ApJL

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

In this letter we focus on the peculiar case of a coalescing compact-object binary whose chirp mass is compatible both with a neutron star-neutron star and black hole-neutron star system, with the black hole in the $\sim 3-5M_\odot$ range defined as the "mass gap". Some models of core-collapse supernovae predict the formation of such low-mass black holes and a recent observation seems to confirm their existence. Here we show that the nature of the companion to the neutron star can be inferred from the properties of the kilonova emission once we know the chirp mass, which is the best constrained parameter inferred from the gravitational signal in low-latency searches. In particular, we find that the kilonova in the black hole-neutron star case is far more luminous than in the neutron star-neutron star case, even when the black hole is non spinning. The difference in the kilonovae brightness arises primarily from the mass ejected during the merger. Indeed, in the considered interval of chirp masses, the mass ejection in double neutron star mergers is at its worst as the system promptly forms a black hole. Instead mass ejection for black hole-neutron star case is at its best as the neutron stars have low mass/large deformability. The kilonovae from black hole-neutron star systems can differ by two to three magnitudes. The outcome is only marginally dependent on the equation of state. The difference is above the systematics in the modeling.

[44]  arXiv:1912.03902 [pdf, ps, other]

Title: Systematic study of the peak energy of the broad-band Gamma-Ray Burst

Authors: Daisuke Katsukura, Takanori Sakamoto, Makoto S. Tashiro, Yukikatsu Terada

Comments: 32 pages, 15 figures, accepted for publication in ApJ

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

We have performed a systematic study of Gamma-Ray Bursts (GRBs), which have various values in the peak energy of the ${\nu}F_{\nu}$ spectrum of the prompt emission, $E_{{\rm peak}}$, observed by \textsl{Swift}/BAT and \textsl{Fermi}/GBM, investigating their prompt and X-ray afterglow emissions. We cataloged the long-lasting GRBs observed by the \textsl{Swift} between 2004 December and 2014 February in 3 categories according to the classification by \citet{2008ApJ...679..570S}: X-Ray Flashes (XRFs), X-Ray Rich GRBs (XRRs), and Classical GRBs (C-GRBs). We then derived $E^{{\rm obs}}_{{\rm peak}}$, as well as $E^{{\rm src}}_{{\rm peak}}$ if viable, of the \textsl{Swift} spectra of their prompt emission. We also analyzed their X-Ray afterglows and found the trend that the GRB events with a lower $E_{{\rm peak}}^{{\rm src}}$, i.e. softer GRBs, are fainter in the 0.3--10 keV X-ray luminosity and decay more slowly than harder GRBs. The intrinsic event rates of the XRFs, XRRs, and C-GRBs were calculated, using the \textsl{Swift}/BAT trigger algorithm. That of either of the XRRs and XRFs is larger than that of the C-GRBs. If we assume that the observational diversity of $E_{{\rm peak}}$ is explained with the off-axis model \citep{2002ApJ...571L..31Y,2004ApJ...607L..103Y}, these results yield the jet half-opening angle of $\Delta\theta\sim 0.3^\circ$, and the variance of the observing angles $\theta_{{\rm obs}} \lesssim0.6^{\circ}$. This implies that the tiny variance of the observing angles of $\lesssim0.6^{\circ}$ would be responsible for the $E_{{\rm peak}}$ diversity observed by \textsl{Swift}/BAT, which is unrealistic. Therefore, we conclude that the $E_{{\rm peak}}$ diversity is not explained with the off-axis model, but is likely to originate from some intrinsic properties of the jets.

[45]  arXiv:1912.03930 [pdf, other]

Title: 3D numerical simulations of oscillations in solar prominences

Authors: A. Adrover-González, J. Terradas

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

Oscillations in solar prominences are a frequent phenomenon, and they have been the subject of many studies. A full understanding of the mechanisms that drive them and their attenuation has not been reached yet. We numerically investigate the periodicity and damping of transverse and longitudinal oscillations in a 3D model of a curtain-shaped prominence. We carried out a set of numerical simulations of vertical, transverse and longitudinal oscillations with the high-order finite-difference Pencil Code. We solved the ideal magnetohydrodynamic (MHD) equations for a wide range of parameters, including the width and density of the prominence, and the magnetic field strength (B) of the solar corona. We studied the periodicity and attenuation of the induced oscillations. We found that longitudinal oscillations can be fit with the pendulum model, whose restoring force is the field aligned component of gravity, but other mechanisms such as pressure gradients may contribute to the movement. On the other hand, transverse oscillations are subject to magnetic forces. The analysis of the parametric survey shows, in agreement with observational studies, that the oscillation period (P) increases with the prominence width. For transverse oscillations we obtained that P increases with density and decreases with B. For longitudinal oscillations we also found that P increases with density, but there are no variations with B. The attenuation of transverse oscillations was investigated by analysing the velocity distribution and computing the Alfv\'en continuum modes. We conclude that resonant absorption is the mean cause. Damping of longitudinal oscillations is due to some kind of shear numerical viscosity.

[46]  arXiv:1912.03933 [pdf, ps, other]

Title: Comment on "Measurement of d + 7Be Cross Sections for Big-Bang Nucleosynthesis"

Authors: Alain Coc, Barry Davids

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

In a recent Letter entitled "Measurement of d + 7Be Cross Sections for Big-Bang Nucleosynthesis", Rijal et al. describe the results of an experiment that put the d + 7Be reaction rate on firmer ground. The erratum of Rijal et al. claims that including this reaction rate in big bang nucleosynthesis brings a significant reduction of up to 8.1% of lithium production relative to calculations that exclude this reaction. In contrast, using several well tested BBN codes, we confirm earlier studies showing that the effect is less than 1%, so that this measurement cannot alleviate the cosmological lithium problem.

[47]  arXiv:1912.03935 [pdf, other]

Title: A spider timing model: accounting for quadrupole deformations and relativity in close pulsar binaries

Authors: Guillaume Voisin (LUTH), René Breton, Charlotte Summers

Journal-ref: Monthly Notices of the Royal Astronomical Society, Oxford University Press (OUP): Policy P - Oxford Open Option A, 2019, 000, pp.1 - 16

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

Spider millisecond pulsars are, along with some eclipsing post-common envelope systems and cataclysmic variables, part of an expanding category of compact binaries with low-mass companions for which puzzling timing anomalies have been observed. The most prominent type of irregularities seen in them are orbital period variations, a phenomenon which has been proposed to originate from changes in the gravitational quadrupole moment of the companion star. A physically sound modelling of the timing of these systems is key to understanding their structure and evolution. In this paper we argue that a complete timing model must account for relativistic corrections as well as rotationally and tidally induced quadrupole distortions. We solve for the resulting orbital dynamics using perturbation theory and derive the corresponding timing model in the low eccentricity limit. We find that the expected strong quadrupole deformation of the companion star results in an effective minimum orbital eccentricity. It is accompanied by a fast periastron precession which, if not taken into account, averages out any measurement of the said eccentricity. We show that, with our model, detection of both eccentricity and precession is likely to be made in many if not all spider pulsar systems. Combined with optical light curves, this will allow us to measure the apsidal motion constant, connecting the quadrupole deformation to the internal structure, and thus opening a new window into probing the nature of their exotic stellar interiors. Moreover, more accurate timing may eventually lead spider pulsars to be used for high-precision timing experiments such as pulsar timing arrays.

[48]  arXiv:1912.03944 [pdf, other]

Title: Lessons learned from 19 years of high-resolution X-ray spectroscopy of galaxy clusters with RGS

Authors: C. Pinto, A. C. Fabian, J. S. Sanders, J. de Plaa

Comments: 6 pages, 5 figures, accepted for publication in Astron. Nachr

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

The intracluster medium (ICM) contains the vast majority of the baryonic matter in galaxy clusters and is heated to X-ray radiating temperatures. X-ray spectroscopy is therefore a key to understand both the morphology and the dynamics of galaxy clusters. Here we recall crucial evolutionary problems of galaxy clusters unveiled by 19 years of high-resolution X-ray spectroscopy with the Reflection Grating Spectrometer (RGS) on board XMM-Newton. Its exquisite combination of effective area, spectral resolution and excellent performance over two decades enabled transformational science and important discoveries such as the lack of strong cooling flows, the constraints on ICM turbulence and cooling-heating balance. The ability of RGS to resolve individual ICM spectral lines reveals in great detail the chemical enrichment in clusters by supernovae and AGB stars. RGS spectra clearly showed that the ICM plasma is overall in thermal equilibrium which is unexpected given the wealth of energetic phenomena such as jets from supermassive black holes and mergers.

[49]  arXiv:1912.03953 [pdf, other]

Title: Spectral characterization of the non-thermal X-ray emission of gamma-ray pulsars

Authors: Francesco Coti Zelati, Diego F. Torres, Jian Li, Daniele Vigano

Comments: MNRAS in press

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

We report on a detailed spectral characterization of the non-thermal X-ray emission for a large sample of gamma-ray pulsars in the second Fermi-LAT catalogue. We outline the criteria adopted for the selection of our sample, its completeness, and critically describe different approaches to estimate the spectral shape and flux of pulsars. We perform a systematic modelling of the pulsars' X-ray spectra using archival observations with XMM-Newton, Chandra, and NuSTAR and extract the corresponding non-thermal X-ray spectral distributions. This set of data is made available online and is useful to confront with predictions of theoretical models.

[50]  arXiv:1912.03954 [pdf, other]

Title: First direct observation of a torsional Alfvén oscillation at coronal heights

Authors: P. Kohutova, E. Verwichte, C. Froment

Comments: 5 pages, 3 figures, accepted for publication in A&A

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

Torsional Alfv\'en waves are promising candidates for transport of energy across different layers of the solar atmosphere and have been theoretically predicted for decades. Previous detections of Alfv\'en waves so far have however mostly relied on indirect signatures. We present a first direct observational evidence of a fully resolved torsional Alfv\'en oscillation of a large-scale structure occurring at coronal heights. We analyse IRIS imaging and spectral observation of a surge resulting from magnetic reconnection between active region prominence threads and surrounding magnetic fieldlines. The IRIS spectral data provides clear evidence of an oscillation in the line-of-sight velocity with a 180{\deg} phase difference between the oscillation signatures at opposite edges of the surge flux tube. This together with an alternating tilt in the Si IV and Mg II k spectra across the flux tube and the trajectories traced by the individual threads of the surge material provides clear evidence of torsional oscillation of the flux tube. Our observation shows that magnetic reconnection leads to the generation of large-scale torsional Alfv\'en waves.

[51]  arXiv:1912.03970 [pdf, ps, other]

Title: Substructure of visibility functions from scattered radio emission of pulsars through space VLBI

Authors: M. V. Popov, N. Bartel, M. S. Burgin, C. R. Gwinn, T. V. Smirnova, V. A. Soglasnov

Comments: 13 pages, 3 figures, 4 tables. Accepted for publication to ApJ

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

We report on the substructure of visibility functions in the delay domain of PSRs B0329+54, B0823+26, B0834+06, B1933+16 and B0833-45 (Vela) observed with earth-earth and RadioAstron space-earth two-element interferometers at frequencies of 324 MHz and 1668 MHz. All visibility functions display unresolved spikes distributed over a range of delays. They are due to band-limited scintillation noise and related to the scattering time. The envelopes for each but the Vela pulsar are well fit by a single Lorentzian which we interpret as being indicative of isotropic scattering on the plane of the sky due to a thin scattering screen between the pulsar and us. In contrast, the envelope for the Vela pulsar needs to be mostly fit by at least two Lorentzians, a narrow and a broad one at the same zero delay. We interpret this characteristic as indicative of anisotropic scattering due to more complex structure of scattering screens in the supernova remnant. The possibility of describing the delay visibility functions by Lorentzians is likely a general property of pulsars and offers a new way of describing scattering parameters of the intervening interstellar medium. Furthermore, for all our pulsars, the unresolved spikes in visibility functions of similar projected baselines were well correlated indicating that the telescopes are located in the same diffraction spot. The correlation vanished for visibilities from largely different baselines, when some radio telescopes are not in the same spot.

[52]  arXiv:1912.03971 [pdf, ps, other]

Title: Evolution of hard X-ray photon index in black-hole X-ray binaries: hints for accretion physics

Authors: Hao Liu (HUST), AiJun Dong (GZNU), ShanShan Weng (NJNU), Qingwen Wu (HUST)

Comments: MNRAS 2019,487,5335

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

The anti- and positive correlations between X-ray photon index and Eddington-scaled X-ray luminosity were found in decay phase of X-ray binary outbursts and a sample of active galactic nuclei in former works. We further systematically investigate the evolution of X-ray spectral index, along the X-ray flux and Eddington ratio in eight outbursts of four black-hole X-ray binaries, where all selected outbursts have observational data from Rossi X-ray Timing Explorer in both rise and decay phases. In the initial rise phase, the X-ray spectral index is anti-correlated with the flux, and the X-ray spectrum quickly softens when the X-ray flux is approaching the peak value. In the decay phase, the X-ray photon index and the flux follow two different positive correlations, and they become anti-correlated again when the X-ray flux is below a critical value, where the anti-correlation part follow the same trend as that found in the initial rise phase. Compared with other X-ray binaries, GRO J1655-40 has an evident lower critical Eddington ratio for the anti- and positive transition, which suggests that its black-hole mass and distance are not well constrained or its intrinsic physic is different.

[53]  arXiv:1912.03972 [pdf, ps, other]

Title: Evidence for changing-look AGNs is caused by change of accretion mode

Authors: Hao liu (HUST), Qingwen Wu (HUST), Bing Lyu (HUST), Zhen Yan (SHAO)

Comments: 16 pages, 3 figures and one table, submitted to ApJ, and comments are welcomed

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

The discovery of changing-look active galactic nuclei (CL AGNs), with appearance and disappearance of broad emission lines and/or with strong variation of line-of-sight column density within a few years, challenges the AGN unification model. We explore the physical mechanisms based on the X-ray spectral evolution for a sample of 15 CL AGNs. We find that the X-ray photon index, $\Gamma$, and Eddington-scaled X-ray luminosity, $L_{\rm 2-10 keV}/L_{\rm Edd}$, follow negative and positive correlations when $L_{\rm 2-10 keV}/L_{\rm Edd}$ is lower and higher than a critical value of $\sim 10^{-3}$. This different X-ray spectral evolution is roughly consistent with the prediction of the accretion-mode transition (e.g., clumpy cold gas or cold disk to advection dominated accretion flow, or vice visa). With quasi-simultaneous X-ray and optical spectrum observations within one year, we find that the CL AGNs observed with and without broad emission lines stay in the positive and negative part of the $\Gamma-L_{\rm 2-10 keV}/L_{\rm Edd}$ correlation respectively. Our result suggest that the change of the accretion mode may be the physical reason for the CL AGNs.

[54]  arXiv:1912.03980 [pdf, other]

Title: Hybrid Physical-Deep Learning Model for Astronomical Inverse Problems

Authors: Francois Lanusse, Peter Melchior, Fred Moolekamp

Comments: 8 pages, accepted submission to the NeurIPS 2019 Machine Learning and the Physical Sciences Workshop

Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Machine Learning (cs.LG)

We present a Bayesian machine learning architecture that combines a physically motivated parametrization and an analytic error model for the likelihood with a deep generative model providing a powerful data-driven prior for complex signals. This combination yields an interpretable and differentiable generative model, allows the incorporation of prior knowledge, and can be utilized for observations with different data quality without having to retrain the deep network. We demonstrate our approach with an example of astronomical source separation in current imaging data, yielding a physical and interpretable model of astronomical scenes.

[55]  arXiv:1912.03986 [pdf, other]

Title: Updated fundamental constant constraints from Planck 2018 data and possible relations to the Hubble tension

Authors: Luke Hart, Jens Chluba

Comments: 8 pages, 8 figures, 4 tables; submitted to MNRAS

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

We present updated constraints on the variation of the fine structure constant, $\alpha_{\rm EM}$, and effective electron rest mass, $m_{\rm e}$, during the cosmological recombination era. These two fundamental constants directly affect the ionization history at redshift $z\simeq 1100$ and thus modify the temperature and polarisation anisotropies of the cosmic microwave background (CMB) measured precisely with {\it Planck }. The constraints on $\\alpha_{\rm EM}$ tighten slightly due to improved {\it Planck} 2018 polarisation data but otherwise remain similar to previous CMB analysis. However, a comparison with the 2015 constraints reveals a mildly discordant behaviour for $m_{\rm e}$, which from CMB data alone is found below its local value. Adding baryon acoustic oscillation data brings $m_{\rm e}$ back to the fiducial value, $m_{\rm e}=(1.0078\pm0.0067) m_{\rm e,0}$, and also drives the Hubble parameter to $H_0=69.1\pm 1.2$ [in units of ${\rm km \, s^{-1} \, Mpc^{-1} }$]. Further adding supernova data yields $m_{\rm e}=(1.0190\pm0.0055) m_{\rm e,0}$ with $H_0=71.24\pm0.96$. We perform several comparative analyses using the latest cosmological recombination calculations to further understand the various effects. Our results indicate that a single-parameter extension allowing for a slightly increased value of $m_{\rm e}$ ($\simeq 3.5\sigma$ above $m_{\rm e,0}$) could play a role in the Hubble tension.

[56]  arXiv:1912.04019 [pdf, other]

Title: Radio Recombination Line Observations Toward the Massive Star Forming Region W51 IRS1

Authors: Mishaal. I. Jan (University of Colorado at Boulder, Boulder), D. Anish Roshi (Arecibo Observatory, Arecibo), M. E. Lebrón (Department of Physical Sciences, University of Puerto Rico, Río Piedras Campus, San Juan), E. Pacheco (Department of Physics, University of Puerto Rico, Río Piedras Campus, San Juan), T. Ghosh (Green Bank Observatory, Green Bank), C. J. Salter (Green Bank Observatory, Green Bank & Arecibo Observatory, Arecibo), R. Minchin (USRA/SOFIA Science Center, NASA Ames Research Center), E. D. Araya (Western Illinois University, Macomb), H. G. Arce (Department of Astronomy, Yale University, New Haven)

Comments: 7 pages, 4 figures, 1 table, To appear in ASPCS Vol. 525, "2020 Compendium of Undergraduate Research in Astronomy and Space Science'', Joseph B. Jensen, Jonathan Barnes, and Beth Wardell, eds. (2020)

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

We observed radio recombination lines (RRLs) toward the W51 molecular cloud complex, one of the most active star forming regions in our Galaxy. The UV radiation from young massive stars ionizes gas surrounding them to produce HII regions. Observations of the W51 IRS1 HII region were made with the Arecibo 305 m telescope. Of the full 1-10 GHz database, we have analyzed the observations between 4.5 and 5 GHz here. The steps involved in the analysis were: a) bandpass calibration using on-source/off-source observations; b) flux density calibration; c) removing spectral baselines due to errors in bandpass calibration and d) Gaussian fitting of the detected lines. We detected alpha, beta and gamma transitions of hydrogen and alpha transitions of helium. We used the observed line parameters to 1) measure the source velocity (56.6 $\pm$ 0.3 km s$^{-1}$) with respect to the Local Standard of Rest (LSR); 2) estimate the electron temperature (8500 $\pm$ 1800 K) of the HII region and 3) derive the emission measure (5.4 $\pm$ 2.7 $\times$ 10$^{6}$ pc cm$^{-6}$) of the ionized gas.

[57]  arXiv:1912.04020 [pdf, other]

Title: The Hi-GAL catalogue of dusty filamentary structures in the Galactic Plane

Authors: E. Schisano, S. Molinari, D. Elia, M. Benedettini, L. Olmi, S. Pezzuto, A. Traficante, M. Brescia, S. Cavuoti, A. M. di Giorgio, S. J. Liu, T. J. T. Moore, A. Noriega-Crespo, G. Riccio, A. Baldeschi, U. Becciani, N. Peretto, M. Merello, F. Vitello, A. Zavagno, M. T. Beltrán, L. Cambrésy, D. J. Eden, G. Li Causi, M. Molinaro, P. Palmeirim, E. Sciacca, L. Testi, G. Umana, A. P. Whitworth

Comments: 38 pages, 29 figures, 3 appendices

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

The recent data collected by {\it Herschel} have confirmed that interstellar structures with filamentary shape are ubiquitously present in the Milky Way. Filaments are thought to be formed by several physical mechanisms acting from the large Galactic scales down to the sub-pc fractions of molecular clouds, and they might represent a possible link between star formation and the large-scale structure of the Galaxy. In order to study this potential link, a statistically significant sample of filaments spread throughout the Galaxy is required. In this work we present the first catalogue of $32,059$ candidate filaments automatically identified in the Hi-GAL survey of the entire Galactic Plane. For these objects we determined morphological (length, $l^{a}$, and geometrical shape) and physical (average column density, $N_{\rm H_{2}}$, and average temperature, $T$) properties. We identified filaments with a wide range of properties: 2$'$\,$\leq l^{a}\leq$\, 100$'$, $10^{20} \leq N_{\rm H_{2}} \leq 10^{23}$\,cm$^{-2}$ and $10 \leq T\leq$ 35\,K. We discuss their association with the Hi-GAL compact sources, finding that the most tenuous (and stable) structures do not host any major condensation and we also assign a distance to $\sim 18,400$ filaments for which we determine mass, physical size, stability conditions and Galactic distribution. When compared to the spiral arms structure, we find no significant difference between the physical properties of on-arm and inter-arm filaments. We compared our sample with previous studies, finding that our Hi-GAL filament catalogue represents a significant extension in terms of Galactic coverage and sensitivity. This catalogue represents an unique and important tool for future studies devoted to understanding the filament life-cycle.

[58]  arXiv:1912.04033 [pdf, other]

Title: Rest-frame UV Properties of Luminous Strong Gravitationally Lensed Ly$α$ Emitters from the BELLS GALLERY Survey

Authors: R. Marques-Chaves, I. Pérez-Fournon, Y. Shu, L. Colina, A. Bolton, J. Álvarez-Márquez, J. Brownstein, M. Cornachione, S. Geier, C. Jiménez-Ángel, T. Kojima, S. Mao, A. Montero-Dorta, M. Oguri, M. Ouchi, F. Poidevin, R. Shirley, Z. Zheng

Comments: 23 pages, 10 figures, 6 tables. Accepted for publication in MNRAS

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

We present deep rest-frame UV spectroscopic observations using the Gran Telescopio Canarias of six gravitationally lensed Lya emitters (LAEs) at $2.36<z<2.82$ selected from the BELLS GALLERY survey. By taking the magnifications into account, we show that LAEs can be as luminous as L(Lya) = 30x10$^{42}$ erg s-1 and M(UV) = -23 (AB) without invoking an AGN component, in contrast with previous findings. We measure Lya rest-frame equivalent widths, EW(Lya), ranging from 16\AA to 50\AA and Lya escape fractions, fesc(Lya), from 10% to 40%. Large EW(Lya) and fesc(Lya) are found predominantly in LAEs showing weak low-ionization ISM absorption (EW < 1\AA) and narrow Lya profiles (< 300 km s-1 FWHM) with their peak close (< 80 km s-1) to their systemic redshifts, suggestive of less scatter from low HI column densities that favours the escape of Lya photons. We infer stellar metallicities of Z/Zsun ~ 0.2 in almost all LAEs by comparing the P-Cygni profiles of the wind lines NV1240\AA and CIV1549\AA with those from stellar synthesis models. We also find a trend between M(UV) and the velocity offset of ISM absorption lines, such as the most luminous LAEs experience stronger outflows. The most luminous LAEs show star formation rates up to 180 Msun yr-1, yet they appear relatively blue ($\beta$(UV) ~ -1.8 to -2.0) showing evidence of little dust attenuation (E(B-V) = 0.10-0.14). These luminous LAEs may be particular cases of young starburst galaxies that have had no time to form large amounts of dust. If so, they are ideal laboratories to study the early phase of massive star formation, stellar and dust mass growth, and chemical enrichment histories of starburst galaxies at high-z.

[59]  arXiv:1912.04043 [pdf, ps, other]

Title: TESS light curves of low-mass detached eclipsing binaries

Authors: Krzysztof G. Hełminiak, Andrés Jordán, Nestor Espinoza, Rafael Brahm

Comments: 5 pages, 1 table, 2 figures, Proceedings of the IAU Symposium 354 "Solar and Stellar Magnetic Fields: Origins and Manifestations" (poster)

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

We present high-precision light curves of several M- and K-type, active detached eclipsing binaries (DEBs), recorded with 2-minute cadence by the Transiting Exoplanet Survey Satellite (TESS). Analysis of these curves, combined with new and literature radial velocity (RV) data, allows to vastly improve the accuracy and precision of stellar parameters with respect to previous studies of these systems. Results for one previously unpublished DEB are also presented.

[60]  arXiv:1912.04053 [pdf, other]

Title: Reconsidering astrophysical constraints on macroscopic dark matter

Authors: Jagjit Singh Sidhu, Glenn D. Starkman

Comments: 9 pages, 1 figure

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

Macroscopic dark matter -- "macros"-- refers to a broad class of alternative candidates to particle dark matter with still unprobed regions of parameter space. These candidates would transfer energy primarily through elastic scattering with approximately their geometric cross-section. For sufficiently large cross-sections, the linear energy deposition could produce observable signals if a macro were to pass through compact objects such as white dwarfs or neutron stars in the form of thermonuclear runaway, leading to a type IA supernova or superburst respectively. We update the constraints from white dwarfs. These are weaker than previously inferred in important respects because of more careful treatment of the passage of a macro through the white dwarf and greater conservatism regarding the size of the region that must be heated to initiate runaway. On the other hand, we place more stringent constraints on macros at low cross-section, using new data from the Montreal White Dwarf Database. New constraints are inferred from the low mass X-ray binary 4U 1820-30, in which more than a decade passed between successive superbursts. Updated microlensing constraints are also reported.

[61]  arXiv:1912.04092 [pdf]

Title: No signature of the orbital motion of a putative 70 solar mass black hole in LB-1

Authors: Michael Abdul-Masih, Gareth Banyard, Julia Bodensteiner, Dominic M. Bowman, Karan Dsilva, Matthias Fabry, Calum Hawcroft, Laurent Mahy, Pablo Marchant, Gert Raskin, Maddalena Reggiani, Hugues Sana, Tomer Shenar, Andrew Tkachenko, Hans Van Winckel, Lore Vermeylen

Comments: 10 pages, 8 figures

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

Liu et al. (2019) recently reported the detection of a 68 [+11/-13] solar mass (Msun) black hole (BH) paired with an 8.2 [+0.9/-1.2] Msun B-type sub-giant star in the 78.9-day spectroscopic binary system LB-1. Such a black hole is over twice as massive as any other known stellar-mass black hole with non-compact companions2 and its mass approaches those that result from BH-BH coalescences that are detected by gravitational wave interferometers. Its presence in a solar-like metallicity environment challenges conventional theories of massive binary evolution, stellar winds and core-collapse supernovae, so that more exotic scenarios seem to be needed to explain the existence and properties of LB-1. Here, we show that the observational diagnostics used to derive the BH mass results from the orbital motion of the B-type star, not that of the BH. As a consequence, no evidence for a massive BH remains in the data, therefore solving the existing tension with formation models of such a massive BH at solar metallicity and with theories of massive star evolution in general.

[62]  arXiv:1912.04095 [pdf, other]

Title: A well aligned orbit for the 45 Myr old transiting Neptune DS Tuc Ab

Authors: G. Zhou, J.N. Winn, E.R. Newton, S.N. Quinn, J.E. Rodriguez, A.W. Mann, A.C. Rizzuto, A.M. Vanderburg, C.X. Huang, D.W. Latham, J.K. Teske, S. Wang, S.A. Shectman, R.P. Butler, J.D. Crane, I. Thompson, T.J. Henry, L.A. Paredes, W.C. Jao, H.S. James, R. Hinojosa

Comments: Submitted to ApJL

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

DS Tuc Ab is a Neptune-sized planet that orbits around a member of the 45 Myr old Tucana-Horologium moving group. Here, we report the measurement of the sky-projected angle between the stellar spin axis and the planet's orbital axis, based on the observation of the Rossiter-McLaughlin effect during three separate planetary transits. The orbit appears to be well aligned with the equator of the host star, with a projected obliquity of lambda = 2.93 +0.88/-0.87 deg. In addition to the distortions in the stellar absorption lines due to the transiting planet, we observed variations that we attribute to large starspots, with angular sizes of tens of degrees. The technique we have developed for simultaneous modeling of starspots and the planet-induced distortions may be useful in other observations of planets around active stars.

[63]  arXiv:1912.04103 [pdf, ps, other]

Title: On using inspiralling supermassive binary black holes in the PTA frequency band as standard sirens to constrain dark energy

Authors: Changshuo Yan, Wen Zhao, Youjun Lu

Comments: 11 pages, 10 figures

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

Supermassive binary black holes (SMBBHs) in galactic centers may radiate gravitational wave (GW) in the nano-Hertz frequency band, which are expected to be detected by pulsar timing arrays (PTAs) in the near future. GW signals from individual SMBBHs at cosmic distances, if detected by PTAs, are potentially powerful standard sirens that can be used to independently measure distances and thus put constraints on cosmological parameters. In this paper, we investigate the constraint that may be obtained on the equation of state ($w$) of dark energy by using those SMBBHs, expected to be detected by the PTAs in the Square Kilometre Array (SKA) era. By considering both the currently available SMBBH candidates and mock SMBBHs in the universe resulting from a simple galaxy major merger model, we find that $\sim 200$ to $3000$ SMBBHs with chirp mass $>10^9M_\odot$ are expected to be detected with signal-to-noise ratio $>10$ by SKA-PTA with conservative and optimistic settings and they can be used to put a constraint on $w$ to an uncertainty of $\Delta w\sim 0.02-0.1$. If further information on the mass and mass ratio of those SMBBHs can be provided by electromagnetic observations (e.g., chirp mass uncertainty $\lesssim 50\%$), the constraint may be further improved to $\lesssim 0.01$ level, as many more SMBBHs will be detected by SKA-PTA with relatively better distance measurements and can be used as the standard sirens.

[64]  arXiv:1912.04118 [pdf, other]

Title: Anisotropies of intrinsic ellipticity correlations in real and redshift space: Angular dependence in linear tidal alignment model

Authors: Teppei Okumura, Atsushi Taruya

Comments: 6 pages, 2 figures

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

Investigating intrinsic alignments (IAs) of galaxy shapes is important not only to constrain cosmological parameters unbiasedly from gravitational lensing but also to extract cosmological information complimentary to galaxy clustering analysis. We derive simple and useful formulas for the various IA statistics, including the intrinsic ellipticity--ellipticity correlation, the gravitational shear--intrinsic ellipticity correlation, and the velocity-intrinsic ellipticity correlation functions. The angular dependence of each statistic is explicitly given, namely the angle between the line-of-sight direction and the separation vector of two points. It thus allows us to analyze anisotropies of baryon acoustic oscillations encoded in the IA statistics, and we can extract the maximum cosmological information using the Alcock-Pacyznski and redshift-space distortion effects. We also provide these formulas for the intrinsic ellipticities decomposed into E- and B-modes.

[65]  arXiv:1912.04120 [pdf, other]

Title: Radial velocity photon limits for the dwarf stars of spectral classes F--M

Authors: Ansgar Reiners, Mathias Zechmeister

Comments: accepted for publication in ApJS; online calculator available at this http URL; full Table 5 available at this http URL

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

The determination of extrasolar planet masses with the radial velocity (RV) technique requires spectroscopic Doppler information from the planet's host star, which varies with stellar brightness and temperature. We analyze Doppler information in spectra of F--M dwarfs utilizing empirical information from HARPS and CARMENES, and from model spectra. We come to the conclusions that an optical setup ($BVR$-bands) is more efficient that a near-infrared one ($YJHK$) in dwarf stars hotter than 3200\,K. We publish a catalogue of 46,480 well-studied F--M dwarfs in the solar neighborhood and compare their distribution to more than one million stars from Gaia DR2. For all stars, we estimate the RV photon noise achievable in typical observations assuming no activity jitter and slow rotation. We find that with an ESPRESSO-like instrument at an 8m-telescope, a photon noise limit of 10\,cm\,s$^{-1}$ or lower can be reached in more than 280 stars in a 5\,min observation. At 4m-telescopes, a photon noise limit of 1\,m\,s$^{-1}$ can be reached in a 10\,min exposure in approx.\ 10,000 predominantly sun-like stars with a HARPS-like (optical) instrument. The same applies to $\sim$3000 stars for a red-optical setup covering the $RIz$-bands, and to $\sim$700 stars for a near-infrared instrument. For the latter two, many of the targets are nearby M dwarfs. Finally, we identify targets in which Earth-mass planets within the liquid water habitable zone can cause RV amplitudes comparable to the RV photon noise. Assuming the same exposure times, we find that an ESPRESSO-like instrument can reach this limit for 1\,M$_\Earth$ planets in more than 1000 stars. The optical, red-optical, and near-infrared configurations reach the limit for 2\,M$_\Earth$ planets in approximately 500, 700, and 200 stars, respectively.

[66]  arXiv:1912.04121 [pdf, ps, other]

Title: What is New with Landstreet Star HD 37776 (V901 Ori)?

Authors: Zdeněk Mikulášek, Jiří Krtička, Matthew E. Shultz, Gregory W. Henry, Milan Prvák, Alexandre David-Uraz, Jan Janík, Iosif I. Romanyuk, MOBSTER collaboration

Comments: 8 pages, 8 figures, JDL workshop proceedings

Journal-ref: PTA Proceedings 2020

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

HD\,37776 (V901\,Ori, B2\,Vp), also known as Landstreet's Star, is possibly the most remarkable magnetic chemically peculiar (mCP) star known. Zeeman Doppler Imaging revealed this young, rapidly rotating star's surface magnetic field to be not only the strongest ($\sim 30$ kG) of the He-strong class of hot mCP stars but also by far the most topologically complex. In contrast to the overwhelming majority of mCP stars, which are well described by tilted dipoles, Landstreet's Star's non-axisymmetric surface magnetic field is entirely dominated by high-order spherical harmonics. It is one of the handful of stars for which rotational period change has been measured, and over the past two decades of monitoring, the object has demonstrated an unexpected acceleration in its rotation that so far defies explanation. Recently acquired TESS data have provided a photometric data set of unprecedented precision. These data have revealed a highly stable yet multi-featured light curve, making Landstreet's Star the prototype of hot mCP stars whose light curves are difficult to reproduce using the standard model of chemical/photometric spots modulated by solid-body rotation.

[67]  arXiv:1912.04129 [pdf, other]

Title: Pulsation in faint blue stars

Authors: Conor M. Byrne, C. Simon Jeffery

Comments: 14 pages, 12 figures, accepted for publication in MNRAS

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

Following the discovery of blue large-amplitude pulsators (BLAPs) by the OGLE survey, additional hot, high-amplitude pulsating stars have been discovered by the Zwicky Transient Facility. It has been proposed that all of these objects are low-mass pre-white dwarfs and that their pulsations are driven by the opacity of iron-group elements. With this expanded population of pulsating objects, it was decided to compute a sequence of post-common-envelope stellar models using the MESA stellar evolution code and to examine the pulsation properties of low-mass pre-white dwarfs using non-adiabatic analysis with the GYRE stellar oscillation code. By including the effects of atomic diffusion and radiative levitation, it is shown that a large region of instability exists from effective temperatures of 30,000 K up to temperatures of at least 50,000 K and at a wide range of surface gravities. This encompasses both groups of pulsator observed so far, and confirms that the driving mechanism is through iron group element opacity. We make some conservative estimates about the range of periods, masses, temperatures and gravities in which further such pulsators might be observed.

[68]  arXiv:1912.04150 [pdf, other]

Title: USco1621 B and USco1556 B: Two wide companions at the deuterium-burning mass limit in Upper Scorpius

Authors: Patricia Chinchilla, Víctor J. S. Béjar, Nicolas Lodieu, Bartosz Gauza, Maria Rosa Zapatero Osorio, Rafael Rebolo, Antonio Pérez Garrido, Carlos Alvarez, Elena Manjavacas

Comments: 17 pages, 15 figures, accepted for publication in A&A

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

(Abridged) Our aim is to identify analogues of gas giant planets, as companions at wide separations of very young stars. To identify these objects, we cross correlated the Visible and Infrared Survey Telescope for Astronomy (VISTA) Hemisphere Survey (VHS) and the United Kingdom Infrared Telescope Infrared Deep Sky Survey Galactic Clusters Survey (UKIDSS GCS) catalogues to search for common proper motion companions to 1195 already known members of Upper Scorpius (USco; age $\sim$5-10 Myr, distance $\sim$145 pc). We present the discovery and spectroscopic characterisation of two very wide substellar companions of two early-M stars in Upper Scorpius: USco1621 B and USco1556 B. We obtained optical and near-infrared low-resolution spectroscopy of the candidates to characterise their spectral energy distribution and confirm their membership to the association. We also acquired adaptive optics images of the primaries and secondaries to search for signs of binarity and close companions. We determined a spectral type of M8.5 in the optical for both companions, along with L0 and L0.5 in the near-infrared for USco1621 B and USco1556 B, respectively. The spectra of the two companions show evident markers of youth. The comparison with theoretical evolutionary models gives estimated masses of 0.015$\pm$0.002 and 0.014$\pm$0.002 M$_{\odot}$, with temperatures of 2270$\pm$90 and 2240$\pm$100 K, respectively. The physical separations between the components of both systems are 2880$\pm$20 and 3500$\pm$40 AU for USco1621 and USco1556 systems, respectively. We did not find any additional close companion in the adaptive optics images. The probability that the two secondaries are physically bound to their respective primaries, and not chance alignments of USco members, is 86%, and the probability that none of them are physically related is 1.0%.

[69]  arXiv:1912.04156 [pdf, ps, other]

Title: Multifrequency Study on The Mode Switching of PSR J0614+2229

Authors: Yanrong Zhang, Hongguang Wang, Xiujian Huang, Jianling Chen

Comments: 13 pages, 3 tables, 7 figures

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

The mode switching phenomenon of PSR J0614+2229 was studied by using the archived observations at 686 MHz, 1369 MHz and 3100 MHz with the Parkes radio telescope which have not been published before, and combining existing observations from the literature. Over a wide frequency range from 327~MHz to 3100~MHz, the pulsar switches between one mode occurring earlier in pulse phase (mode A) and the other mode appearing later in phase (mode B), with a generally stable phase offset between their profile peaks. The two modes are found to be different in the following aspects. (1) Mode A has a flatter spectrum than mode B does, with a difference in the spectral index about 0.5. This accounts for the phenomenon that the flux ratio between the modes A and B increases with frequency and mode A becomes stronger than mode B above $\sim500$ MHz. (2) For mode B, the flux density of the sub-integrated profile is anti-correlated with the emission phase, indicating that the emission from earlier phases is relatively stronger than that from later phases. But such an anti-correlation is not observed in mode A. (3) The frequency dependence of the full width of half maximum (FWHM) of the two modes are opposite to each other, namely the FWHM of mode A increases with frequency, while that of mode B decreases with frequency. A possible interpretation is suggested that the longitudinal spectral variation across the two beams may be opposite to each other. In mode A, the spectrum should steepen from the edge to the center of the beam. When the emission switches to mode B, the spectral variation should be reversed.

[70]  arXiv:1912.04167 [pdf, ps, other]

Title: KIC 8840638: A new Eclipsing Binary Consisting of a $δ$ Scuti star with multiperiodic pulsations

Authors: Tao-Zhi Yang, Junhui Liu, Zhaoyu Zuo

Comments: Comments are welcomed. arXiv admin note: text overlap with arXiv:1612.09408 by other authors

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

In this paper, we present an analysis of the $Kepler$ high-precision observations of KIC 8840638. The analysis indicates the target KIC 8840638 is an eclipsing binary with a $\delta$ Scuti component, not a pure single $\delta$ Scuti star previously known. The frequency analysis of the high-precision short cadence light curve reveals 95 significant frequencies, most of them lies in the frequency range of 23$-$32 d$^{-1}$. Among them, 7 independent frequencies are detected in the typical frequency range of the $\delta$ Scuti variables. In addition, the orbital frequency $f_{orb}$ (=0.320008 d$^{-1}$) and its harmonic are also detected directly in the frequency spectrum. The binary modeling using the Wilson-Devinney code indicate the binary system is in a semi-detached configures with a mass ratio of 1.6, an inclination angle of 16.9 degree, and a temperature difference of larger than 3000 K between the components. The locations of the components of KIC 8840638 indicate the primary star lies in the $\delta$ Scuti instability region below the terminal-age main-sequence, and the secondary star might be a evolved star.

[71]  arXiv:1912.04185 [pdf, other]

Title: Not so fast: LB-1 is unlikely to contain a 70 $M_{\odot}$ black hole

Authors: Kareem El-Badry, Eliot Quataert

Comments: 5 pages, 4 figures. Comments welcome. Submitted to MNRAS letters

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

The recently discovered binary system LB-1 has been reported to contain a $\sim 70\,M_{\odot}$ black hole (BH). The evidence for the unprecedentedly high mass of the unseen companion comes from reported radial velocity (RV) variability of the H$\alpha$ emission line, which has been proposed to originate from an accretion disk around a BH. We show that there is in fact no evidence for RV variability of the H$\alpha$ emission line, and that its apparent shifts instead originate from shifts in the luminous star's H$\alpha$ absorption line. If not accounted for, such shifts will always cause a stationary emission line to appear to shift in anti-phase with the luminous star. We show that once the template spectrum of a B star is subtracted from the observed Keck/HIRES spectra of LB-1, evidence for RV variability vanishes. Indeed, the data rule out any periodic variability of the emission line with velocity semi-amplitude $K_{\rm H\alpha} > 1.3\,\rm km\,s^{-1}$. This strongly suggests that the observed H$\alpha$ emission does not originate primarily from an accretion disk around a BH, and thus that the mass ratio cannot be constrained from the relative velocity amplitudes of the emission and absorption lines. The nature of the unseen companion remains uncertain, but a "normal" stellar-mass BH with mass $5\lesssim M/M_{\odot}\lesssim 20 $ seems most plausible. The H$\alpha$ emission likely originates primarily from circumbinary material, not from either component of the binary.

[72]  arXiv:1912.04197 [pdf, other]

Title: A parallel-GPU code for asteroid aggregation problems with angular particles

Authors: F. Ferrari, M. Lavagna, E. Blazquez

Comments: 15 pages and 8 figures. Accepted in Monthly Notices of the Royal Astronomical Society

Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Numerical Analysis (math.NA)

The paper presents a numerical implementation of the gravitational N-body problem with contact interactions between non-spherically shaped bodies. The work builds up on a previous implementation of the code and extends its capabilities. The number of bodies handled is significantly increased through the use of a CUDA/GPU-parallel octree structure. The implementation of the code is discussed and its performance are compared against direct N$^2$ integration. The code features both smooth (force-based) and non-smooth (impulse-based) methods, as well as a visco-elastic non-smooth method, to handle contact interaction between bodies. The numerical problem of simulating "rubble-pile" asteroid gravitational aggregation processes is addressed. We discuss the features of the problem and derive criteria to set up the numerical simulation from the dynamical constraints of the combined gravitational-collisional problem. Examples of asteroid aggregation scenarios that could benefit from such implementation are finally presented.

[73]  arXiv:1912.04236 [pdf, ps, other]

Title: Chemical abundances of Seyfert 2 AGNs I. Comparing oxygen abundances from distinct methods using SDSS

Authors: O. L. Dors, P. Freitas-Lemes, E. B. Amores, E. Perez-Montero, M. V. Cardaci, G. F. Hagele, M. Armah, A. C. Krabbe, M. Faundez-Abans

Comments: 12 pages, 7 figures, accepted for publication in MNRAS

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

We compare the oxygen abundance (O/H) of the Narrow Line Regions (NLRs) of Seyfert 2 AGNs obtained through strong-line methods and from direct measurements of the electron temperature (Te-method). The aim of this study is to explore the effects of the use of distinct methods on the range of metallicity and on the mass-metallicity relation of AGNs at low redshifts (z < 0.4). We used the Sloan Digital Sky Survey (SDSS) and NASA/IPAC Extragalactic Database (NED) to selected optical (3000 < A < 7000) emission line intensities of 463 confirmed Seyfert 2 AGNs. The oxygen abundance of the NLRs were estimated using the theoretical Storchi-Bergmann et al. calibrations, the semi-empirical N2O2 calibration, the bayesian Hii-Chi-mistry code and the Te-method. We found that the oxygen abundance estimations via the strong-line methods differ from each other up to ~0.8 dex, with the largest discrepancies in the low metallicity regime (12 + log(O/H) . 8.5). We confirmed that the Te-method underestimates the oxygen abundance in NLRs, producing unreal subsolar values. We did not find any correlation between the stellar mass of the host galaxies and the metallicity of their AGNs. This result is independent of the method used to estimate Z.

[74]  arXiv:1912.04257 [pdf, ps, other]

Title: A response to Rubin & Heitlauf: "Is the expansion of the universe accelerating? All signs \emph{still} point to yes"

Authors: Jacques Colin, Roya Mohayaee, Mohamed Rameez, Subir Sarkar

Comments: 4 pages

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

We have shown (Colin et al. 2019) that the acceleration of the Hubble expansion rate inferred from Type Ia supernovae is essentially a dipole with 3.9$\sigma$ significance, approximately aligned with the CMB dipole, while its monopole component which may be interpreted as due to a Cosmological Constant (or more generally dark energy) is consistent with zero at 1.4$\sigma$. This is challenged by Rubin & Heitlauf (2019) who assert that we incorrectly assumed the supernova light-curve parameters to be independent of redshift, and erred further in considering their measured redshifts (in the heliocentric frame) rather than transforming them to the CMB frame (in which the universe supposedly looks isotropic). We emphasize that our procedure is justified and that their criticism serves only to highlight the rather "arbitrary corrections" that are made to the data in order to infer isotropic cosmic acceleration. This is a vivid illustration of the 'Cosmological Fitting Problem' faced by observers who live in an inhomogeneous universe but still use the maximally symmetric FLRW cosmolgy to interpret observations.

[75]  arXiv:1912.04268 [pdf, other]

Title: Eclipses of continuous gravitational waves as a probe of stellar structure

Authors: Pablo Marchant, Katelyn Breivik, Christopher P. L. Berry, Ilya Mandel, Shane L. Larson

Comments: Accepted for publication in Physical Review D

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

Although gravitational waves only interact weakly with matter, their propagation is affected by a gravitational potential. If a gravitational wave source is eclipsed by a star, measuring these perturbations provides a way to directly measure the distribution of mass throughout the stellar interior. We compute the expected Shapiro time delay, amplification and deflection during an eclipse, and show how this can be used to infer the mass distribution of the eclipsing body. We identify continuous gravitational waves from neutron stars as the best candidates to detect this effect. When the Sun eclipses a far-away source, depending on the depth of the eclipse the time-delay can change by up to $\sim 0.034$ ms, the gravitational-wave strain amplitude can increase by $\sim 4$%, and the apparent position of the source in the sky can vary by $4''$. Accreting neutron stars with Roche-lobe filling companion stars have a high probability of exhibiting eclipses, producing similar time delays but undetectable changes in amplitude and sky location. Even for the most rapidly rotating neutron stars, this time delay only corresponds to a few percent of the phase of the gravitational wave, making it an extremely challenging measurement. However, if sources of continuous gravitational waves exist just below the limit of detection of current observatories, next-generation instruments will be able to observe them with enough precision to measure the signal of an eclipsing star. Detecting this effect would provide a new direct probe to the interior of stars, complementing asteroseismology and the detection of solar neutrinos.

Cross-lists for Tue, 10 Dec 19

[76]  arXiv:1911.09060 (cross-list from gr-qc) [pdf, ps, other]

Title: Thermodynamic Equilibrium in General Relativity

Authors: J. A. S. Lima (Departamento de Astronomia, Universidade de Sao Paulo), A. Del Popolo (Catania University), A. R. Plastino (CeBio y Departamento de Ciencias Basicas, Universidad Nacional del Noroeste de la Provincia de Buenos Aires, UNNOBA)

Comments: 7 pages, 2 figures, PRD accepted

Journal-ref: PRD 2009, volume 100, 104042; https://journals.aps.org/prd/abstract/10.1103/PhysRevD.100.104042

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

The thermodynamic equilibrium condition for a static self-gravitating fluid in the Einstein theory is defined by the Tolman-Ehrenfest temperature law, $T{\sqrt {g_{00}(x^{i})}} = constant$, according to which the proper temperature depends explicitly on the position within the medium through the metric coefficient $g_{00}(x^{i})$. By assuming the validity of Tolman-Ehrenfest "pocket temperature", Klein also proved a similar relation for the chemical potential, namely, $\mu {\sqrt {g_{00}(x^{i})}} = constant$. In this letter we prove that a more general relation uniting both quantities holds regardless of the equation of state satisfied by the medium, and that the original Tolman-Ehrenfest law form is valid only if the chemical potential vanishes identically. In the general case of equilibrium, the temperature and the chemical potential are intertwined in such a way that only a definite (position dependent) relation uniting both quantities is obeyed. As an illustration of these results, the temperature expressions for an isothermal gas (finite spherical distribution) and a neutron star are also determined.

[77]  arXiv:1912.03424 (cross-list from physics.space-ph) [pdf, other]

Title: Observations of Energetic-Particle Population Enhancements along Intermittent Structures near the Sun from Parker Solar Probe

Authors: Riddhi Bandyopadhyay, W. H. Matthaeus, T. N. Parashar, R. Chhiber, D. Ruffolo, M. L. Goldstein, B. A. Maruca, A. Chasapis, R. Qudsi, D. J. McComas, E. R. Christian, J. R. Szalay, C. J. Joyce, J. Giacalone, N. A. Schwadron, D. G. Mitchell, M. E. Hill, M. E. Wiedenbeck, R. L. McNutt Jr., M. I. Desai, Stuart D. Bale, J. W. Bonnell, Thierry Dudok de Wit, Keith Goetz, Peter R. Harvey, Robert J. MacDowall, David M. Malaspina, Marc Pulupa, M. Velli, J.C. Kasper, K.E. Korreck, M. Stevens, A.W. Case, N. Raouafi

Comments: Submitted to ApJS, PSP special issue

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

Observations at 1 au have confirmed that enhancements in measured energetic particle fluxes are statistically associated with "rough" magnetic fields, i.e., fields having atypically large spatial derivatives or increments, as measured by the Partial Variance of Increments (PVI) method. One way to interpret this observation is as an association of the energetic particles with trapping or channeling within magnetic flux tubes, possibly near their boundaries. However, it remains unclear whether this association is a transport or local effect; i.e., the particles might have been energized at a distant location, perhaps by shocks or reconnection, or they might experience local energization or re-acceleration. The Parker Solar Probe (PSP), even in its first two orbits, offers a unique opportunity to study this statistical correlation closer to the corona. As a first step, we analyze the separate correlation properties of the energetic particles measured by the \isois instruments during the first solar encounter. The distribution of time intervals between a specific type of event, i.e., the waiting time, can indicate the nature of the underlying process. We find that the \isois observations show a power-law distribution of waiting times, indicating a correlated (non-Poisson) distribution. Analysis of low-energy \isois data suggests that the results are consistent with the 1 au studies, although we find hints of some unexpected behavior. A more complete understanding of these statistical distributions will provide valuable insights into the origin and propagation of solar energetic particles, a picture that should become clear with future PSP orbits.

[78]  arXiv:1912.03608 (cross-list from physics.space-ph) [pdf, other]

Title: Clustering of Intermittent Magnetic and Flow Structures near Parker Solar Probe's First Perihelion -- A Partial-Variance-of-Increments Analysis

Authors: Rohit Chhiber, M. Goldstein, B. Maruca, A. Chasapis, W. Matthaeus, D. Ruffolo, R. Bandyopadhyay, T. Parashar, R. Qudsi, T. Dudok de Wit, S. Bale, J. Bonnell, K. Goetz, P. Harvey, R. MacDowall, D. Malaspina, M. Pulupa, J. Kasper, K. Korreck, A. Case, M. Stevens, P. Whittlesey, D. Larson, R. Livi, M. Velli, N. Raouafi

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

During the Parker Solar Probe's (PSP) first perihelion pass, the spacecraft reached within a heliocentric distance of \(\sim 37~R_\odot\) and observed numerous magnetic and flow structures characterized by sharp gradients. To better understand these intermittent structures in the young solar wind, an important property to examine is their degree of correlation in time and space. To this end, we use the well-tested Partial Variance of Increments (PVI) technique to identify intermittent events in FIELDS and SWEAP observations of magnetic and proton-velocity fields (respectively) during PSP's first solar encounter, when the spacecraft was within 0.25 au from the Sun. We then examine distributions of waiting times between events with varying separation and PVI thresholds. We find power-law distributions for waiting times shorter than a characteristic scale comparable to the correlation time, suggesting a high degree of correlation that may originate in a clustering process. Waiting times longer than this characteristic time are better described by an exponential, suggesting a random memory-less Poisson process at play. These findings are consistent with near-Earth observations of solar wind turbulence. The present study complements the one by Dudok de Wit et al. (2020, present volume), which focuses on waiting times between observed "switchbacks" in the radial magnetic field.

[79]  arXiv:1912.03695 (cross-list from hep-ph) [pdf, other]

Title: Probing the scale of grand unification with gravitational waves

Authors: Wilfried Buchmuller, Valerie Domcke, Hitoshi Murayama, Kai Schmitz

Comments: 6 pages, 3 figures

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

The spontaneous breaking of $U(1)_{B-L}$ around the scale of grand unification can simultaneously account for hybrid inflation, leptogenesis, and neutralino dark matter, thus resolving three major puzzles of particle physics and cosmology in a single predictive framework. The B-L phase transition also results in a network of cosmic strings. If strong and electroweak interactions are unified in an SO(10) gauge group, containing $U(1)_{B-L}$ as a subgroup, these strings are metastable. In this case, they produce a stochastic background of gravitational waves that evades current pulsar timing bounds, but features a flat spectrum with amplitude $h^2\Omega_\text{GW} \sim 10^{-8}$ at interferometer frequencies. Ongoing and future LIGO observations will hence probe the scale of B-L breaking.

[80]  arXiv:1912.03701 (cross-list from gr-qc) [pdf, other]

Title: Hamilton-Jacobi hydrodynamics of pulsating relativistic stars

Authors: John Ryan Westernacher-Schneider, Charalampos Markakis, Bing Jyun Tsao

Comments: 24 pgs, 3 figs

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

The dynamics of self-gravitating fluid bodies is described by the Euler-Einstein system of partial differential equations. The break-down of well-posedness on the fluid-vacuum interface remains a challenging open problem, which is manifested in simulations of oscillating or inspiraling binary neutron-stars. We formulate and implement a well-posed canonical hydrodynamic scheme, suitable for neutron-star simulations in numerical general relativity. The scheme uses a variational principle by Carter-Lichnerowicz stating that barotropic fluid motions are conformally geodesic and Helmholtz's third theorem stating that initially irrotational flows remain irrotational. We apply this scheme in 3+1 numerical general relativity to evolve the canonical momentum of a fluid element via the Hamilton-Jacobi equation. We explore a regularization scheme for the Euler equations, that uses a fiducial atmosphere in hydrostatic equilibrium and allows the pressure to vanish, while preserving strong hyperbolicity on the vacuum boundary. The new regularization scheme resolves a larger number of radial oscillation modes compared to standard, non-equilibrium atmosphere treatments.

[81]  arXiv:1912.03868 (cross-list from gr-qc) [pdf, other]

Title: Search for traversable wormholes in active galactic nuclei using X-ray data

Authors: Ashutosh Tripathi, Biao Zhou, Askar B. Abdikamalov, Dimitry Ayzenberg, Cosimo Bambi

Comments: 10 pages, 7 figures

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

In a previous paper, one of us calculated iron K$\alpha$ line profiles emitted from possible accretion disks around traversable wormholes as a first step to use X-ray reflection spectroscopy to search for astrophysical wormholes in active galactic nuclei. In the present paper, we extend that work and construct an XSPEC model for the whole relativistic reflection spectrum. We apply our model to XMM-Newton and NuSTAR observations of the supermassive object in MCG-6-30-15 and we check whether these observations prefer the hypothesis that the central body is a Kerr black hole or a traversable wormhole. We find that the two models provide equally good fits, so with the available data we cannot distinguish the black hole and wormhole scenarios.

[82]  arXiv:1912.03882 (cross-list from gr-qc) [pdf, ps, other]

Title: Cosmological applications of Myrzakulov gravity

Authors: Emmanuel N. Saridakis, Shynaray Myrzakul, Kairat Myrzakulov, Koblandy Yerzhanov

Comments: 9 pages, 4 figures

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

We investigate the cosmological applications of Myrzakulov $F(R,T)$ gravity. In this theory ones uses a specific but non-special connection, and thus both curvature and torsion are dynamical fields related to gravity. We introduce a parametrization that quantifies the deviation of curvature and torsion scalars form their corresponding values obtained using the special Levi-Civita and Weitzenb\"{o}ck connections, and we extract the cosmological field equations following the mini-super-space procedure. Even for the simple case where the action of the theory is linear in $R$ and $T$, we find that the Friedmann equations contain new terms of geometrical origin, reflecting the non-special connection. Applying the theory at late times we find that we can acquire the thermal history of the universe, where dark energy can be quintessence-like or phantom-like, or behave exactly as a cosmological constant and thus reproducing $\Lambda$CDM cosmology. Furthermore, we show that these features are obtained for other Lagrangian choices, too. Finally, early-time application leads to the de Sitter solution, as well as to an inflationary realization with the desired scale-factor evolution.

[83]  arXiv:1912.04008 (cross-list from hep-ph) [pdf, other]

Title: Global fit of pseudo-Nambu-Goldstone Dark Matter

Authors: Chiara Arina, Ankit Beniwal, Céline Degrande, Jan Heisig, Andre Scaffidi

Comments: 35 pages, 10 figures, 2 tables

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

We perform a global fit within the pseudo-Nambu-Goldstone dark matter (DM) model emerging from an additional complex scalar singlet with a softly broken global U(1) symmetry. Leading to a momentum-suppressed DM-nucleon cross section at tree level, the model provides a natural explanation for the null results from direct detection experiments. Our global fit combines constraints from perturbative unitarity, DM relic abundance, Higgs invisible decay, electroweak precision observables and latest Higgs searches at colliders. The results are presented in both frequentist and Bayesian statistical frameworks. Furthermore, post-processing our samples, we include the likelihood from gamma-ray observations of $\mathit{Fermi}$-LAT dwarf spheroidal galaxies and compute the one-loop DM-nucleon cross section. We find two favoured regions characterised by their dominant annihilation channel: the Higgs funnel and annihilation into Higgs pairs. Both are compatible with current $\mathit{Fermi}$-LAT observations, and furthermore, can fit the slight excess observed in four dwarfs in a mass range between about 30-300 GeV. While the former region is hard to probe experimentally, the latter can partly be tested by current observations of cosmic-ray antiprotons as well as future gamma-ray observations.

[84]  arXiv:1912.04149 (cross-list from hep-ph) [pdf, other]

Title: Bounds on non-standard interactions of neutrinos from IceCube DeepCore data

Authors: S.V.Demidov

Comments: 11 pages, 8 figures

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

New physics in neutrino sector can reveal itself via non-standard neutrino interactions which can result in modification of the standard picture of neutrino propagation in matter. Experiments with atmospheric neutrinos has been used to probe this scenario. Using publicly available three-year low energy data in IceCube DeepCore we place bounds on the parameters $\epsilon_{\alpha\beta}$ of non-standard neutrino interactions in propagation. We obtain restrictive constraints not only for $\mu\tau$ sector but also for flavor changing interactions involving electron neutrinos.

[85]  arXiv:1912.04188 (cross-list from hep-ph) [pdf, other]

Title: Connection between $νn \rightarrow \barν \bar{n}$ reactions and $n$-$\bar{n}$ oscillations via additional Higgs triplets

Authors: Yongliang Hao

Comments: 3 tables, 6 figures, and 15 pages

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

In this work, we investigate the connection and compatibility between $\nu n \rightarrow \bar{\nu} \bar{n}$ reactions and $n$-$\bar{n}$ oscillations based on the $SU(3)_c \times SU(2)_L \times U(1)$ symmetry model with additional Higgs triplets. We explore the possibility that the scattering process $\nu n\rightarrow \bar{\nu}\bar{n}$ produced by low-energy solar neutrinos gives rise to an unavoidable background in the measurements of $n$-$\bar{n}$ oscillations. We focus on two different scenarios, depending on whether the $(B-L)$ symmetry could be broken. We analyze the interplay of the various constraints on the two processes and their observable consequences. In the scenario where both $(B+L)$ and $(B-L)$ could be broken, we point out that if all the constraints, mainly arising from the type-II seesaw mechanism, are satisfied, the parameter space would be severely constrained. In this case, although the masses of the Higgs triplet bosons could be within the reach of a direct detection at the LHC or future high-energy experiments, the predicted $n$-$\bar{n}$ oscillation times would be completely beyond the detectable regions of the present experiments. In both scenarios, the present experiments cannot distinguish a $\nu n \rightarrow \bar{\nu} \bar{n}$ reaction event from a $n$-$\bar{n}$ oscillation event within the accessible energy range. Nevertheless, if any of the two processes is detected, there could be signal associated with new physics beyond the Standard Model.

[86]  arXiv:1912.04213 (cross-list from gr-qc) [pdf, ps, other]

Title: On Average Properties of Inhomogeneous Fluids in General Relativity III: General Fluid Cosmologies

Authors: Thomas Buchert, Pierre Mourier, Xavier Roy

Comments: 67 pages, 4 figures, 1 table

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

We investigate effective equations governing the volume expansion of spatially averaged portions of inhomogeneous cosmologies in spacetimes filled with an arbitrary fluid. This work is a follow-up to previous studies focused on irrotational dust models (Paper~I) and irrotational perfect fluids (Paper~II) in flow-orthogonal foliations of spacetime. It complements them by considering arbitrary foliations, arbitrary lapse and shift, and by allowing for a tilted fluid flow with vorticity. As for the first studies, the propagation of the spatial averaging domain is chosen to follow the congruence of the fluid, which avoids unphysical dependencies in the averaged system that is obtained. We present two different averaging schemes and corresponding systems of averaged evolution equations providing generalizations of Papers~I and II. The first one retains the averaging operator used in several other generalizations found in the literature. We extensively discuss relations to these formalisms and pinpoint limitations, in particular regarding rest mass conservation on the averaging domain. The alternative averaging scheme that we subsequently introduce follows the spirit of Papers~I and II and focuses on the fluid flow and the associated $1+3$ threading congruence, used jointly with the $3+1$ foliation that builds the surfaces of averaging. This results in compact averaged equations with a minimal number of cosmological backreaction terms. We highlight that this system becomes especially transparent when applied to a natural class of foliations which have constant fluid proper time slices.

Replacements for Tue, 10 Dec 19

[87]  arXiv:1811.10084 (replaced) [pdf, other]

Title: The Density Structure of Simulated Stellar Streams

Authors: Raymond G. Carlberg

Comments: ApJ accepted. Fig1 movies available at this https URL and movie10_461.mmp4 (+/-60 and 10 kpc boxes centered on star cluster)

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

[88]  arXiv:1811.12617 (replaced) [pdf, ps, other]

Title: Imaging black holes through AdS/CFT

Authors: Koji Hashimoto, Shunichiro Kinoshita, Keiju Murata

Comments: 22 pages, 12 figures

Subjects: High Energy Physics - Theory (hep-th); High Energy Astrophysical Phenomena (astro-ph.HE); Strongly Correlated Electrons (cond-mat.str-el); General Relativity and Quantum Cosmology (gr-qc)

[89]  arXiv:1902.03448 (replaced) [pdf, other]

Title: The multi-scale nature of the solar wind

Authors: Daniel Verscharen (UCL/MSSL, UNH), Kristopher G. Klein (UA), Bennett A. Maruca (UD)

Comments: 155 pages, 24 figures

Journal-ref: Living Rev. Solar Phys. 16, 5, 2019

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

[90]  arXiv:1903.01483 (replaced) [pdf, other]

Title: Identifying reionization-epoch galaxies with extreme levels of Lyman continuum leakage in James Webb Space Telescope surveys

Authors: Sambit K. Giri, Erik Zackrisson, Christian Binggeli, Kristiaan Pelckmans, Rubén Cubo

Comments: 10 pages, 7 figures. Accepted to be published in MNRAS

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

[91]  arXiv:1903.10016 (replaced) [pdf, ps, other]

Title: Kinematics of disk galaxies in (proto-)clusters at z=1.5

Authors: A. Boehm, B.L. Ziegler, J.M. Perez-Martinez, T. Kodama, M. Hayashi, C. Maier, M. Verdugo, Y. Koyama

Comments: Accepted for publication in A&A. 11 pages, 8 figures, 1 table

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

[92]  arXiv:1904.02723 (replaced) [pdf, other]

Title: EDGE: the mass-metallicity relation as a critical test of galaxy formation physics

Authors: Oscar Agertz, Andrew Pontzen, Justin I. Read, Martin P. Rey, Matthew Orkney, Joakim Rosdahl, Romain Teyssier, Robbert Verbeke, Michael Kretschmer, Sarah Nickerson

Comments: 17 pages, 6 figures, Minor changes to mach published MNRAS version

Journal-ref: MNRAS, 2019, Volume 491, Issue 2, p.1656-1672

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

[93]  arXiv:1905.04378 (replaced) [pdf, other]

Title: Large-Scale Mixing in a Violent Oxygen-Neon Shell Merger Prior to a Core-Collapse Supernova

Authors: Naveen Yadav (1 and 2), Bernhard Müller (3 and 4), Hans Thomas Janka (1), Tobias Melson (1), Alexander Heger (5, and 6) ((1) Max Planck Institute for Astrophysics, (2) Exzellenzcluster ORIGINS, (3) Queen's University Belfast, (4) Monash University, (5) Michigan State University, (6) Shanghai Jiao-Tong University)

Comments: 23 pages, 18 figure, Accepted to The ApJ (matches the accepted version)

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

[94]  arXiv:1905.09973 (replaced) [pdf, other]

Title: Anatomy of a thermal black hole mimicker

Authors: Jing Ren

Comments: 25 pages, 3 figures, 1 table; minor corrections, matches published version

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

[95]  arXiv:1906.05649 (replaced) [pdf, other]

Title: When H II Regions are Complicated: Considering Perturbations from Winds, Radiation Pressure, and Other Effects

Authors: Sam Geen, Eric Pellegrini, Rebekka Bieri, Ralf Klessen

Comments: 20 pages, 13 figures, accepted by MNRAS

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

[96]  arXiv:1907.04872 (replaced) [pdf, other]

Title: Spiral-wave wind for the blue kilonova

Authors: Vsevolod Nedora, Sebastiano Bernuzzi, David Radice, Albino Perego, Andrea Endrizzi, Néstor Ortiz

Comments: 5 pages, 4 figures

Journal-ref: The Astrophysical Journal Letters, Volume 886, Number 2 (2019)

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

[97]  arXiv:1907.05909 (replaced) [pdf, other]

Title: Can Assembly Bias Explain the Lensing Amplitude of the BOSS CMASS Sample in a Planck Cosmology?

Authors: Sihan Yuan, Daniel J. Eisenstein, Alexie Leauthaud

Comments: 13 pages, 8 figures, submitted to MNRAS, comments welcomed

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

[98]  arXiv:1907.13205 (replaced) [pdf, other]

Title: Disentangling magnification in combined shear-clustering analyses

Authors: Leander Thiele, Christopher A. J. Duncan, David Alonso

Comments: 13 pages, 7 figures; matches MNRAS published version

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

[99]  arXiv:1908.00290 (replaced) [pdf, other]

Title: ISiTGR: Testing deviations from GR at cosmological scales including dynamical dark energy, massive neutrinos, functional or binned parametrizations, and spatial curvature

Authors: Cristhian Garcia-Quintero, Mustapha Ishak, Logan Fox, Jason Dossett

Comments: 28 pages, 10 figures; matches published version; code publicly available at this https URL

Journal-ref: Phys. Rev. D 100, 103530 (2019)

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

[100]  arXiv:1908.00556 (replaced) [pdf, other]

Title: HST Imaging of the Ionizing Radiation from a Star-forming Galaxy at z = 3.794

Authors: Zhiyuan Ji, Mauro Giavalisco, Eros Vanzella, Brian Siana, Laura Pentericci, Anne Jaskot, Teng Liu, Mario Nonino, Henry C. Ferguson, Marco Castellano, Filippo Mannucci, Daniel Schaerer, Johan Peter Uldall Fynbo, Casey Papovich, Adam C. Carnall, Ricardo Amorin, Raymond C. Simons, Nimish Hathi, Fergus Cullen, Derek McLeod

Comments: 24 pages, 13 figures, accepted for publication in ApJ

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

[101]  arXiv:1908.04888 (replaced) [pdf, other]

Title: Thermal evolution of neo-neutron stars. I: envelopes, Eddington luminosity phase and implications for GW170817

Authors: Mikhail V. Beznogov, Dany Page, Enrico Ramirez-Ruiz

Comments: 23 pages, 19 figures; accepted for publication in ApJ

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

[102]  arXiv:1908.05484 (replaced) [pdf, other]

Title: CMB sky for an off-center observer in a local void I: framework for forecasts

Authors: Viraj Nistane, Giulia Cusin, Martin Kunz

Comments: 24 pages, 8 figures, updated to match version published in JCAP. arXiv admin note: text overlap with arXiv:astro-ph/0607334, arXiv:astro-ph/0512006 by other authors

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

[103]  arXiv:1908.07160 (replaced) [pdf, other]

Title: Modified Gravity Theories in Light of the Anomalous Velocity Dispersion of NGC1052-DF2

Authors: Tousif Islam, Koushik Dutta

Comments: 7 pages, 6 figures; matches the published version

Journal-ref: Phys. Rev. D 100, 104049 (2019)

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

[104]  arXiv:1908.08694 (replaced) [pdf, other]

Title: Stochastic inflation with an extremely large number of $e$-folds

Authors: Naoya Kitajima, Yuichiro Tada, Fuminobu Takahashi

Comments: 6 pages, 3 figures; v2: published version, Fig. 1 added, Figs. 2 & 3 revised

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

[105]  arXiv:1908.08822 (replaced) [pdf, other]

Title: Electromagnetic counterparts of black hole-neutron star mergers: dependence on the neutron star properties

Authors: C. Barbieri, O. S. Salafia, A. Perego, M. Colpi, G. Ghirlanda

Comments: 22 pages, 20 figures. Accepted for publication on EPJA, in Topical Issue "First joint gravitational wave and electromagnetic observations: Implications for nuclear and particle physics"

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

[106]  arXiv:1908.09061 (replaced) [pdf, other]

Title: The effect of fluctuating fuzzy axion haloes on stellar dynamics: a stochastic model

Authors: Amr El-Zant, Jonathan Freundlich, Francoise Combes, Anaelle Halle

Comments: Additional comments on the conditions for the description in terms of effective quasi-particle mass, and the 'Jeans-Chandrasekhar swindle'. References added. To appear in Monthly Notices

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

[107]  arXiv:1908.10026 (replaced) [pdf, other]

Title: Faint Repetitions from a Bright Fast Radio Burst Source

Authors: Pravir Kumar, R. M. Shannon, Stefan Osłowski, Hao Qiu, Shivani Bhandari, Wael Farah, Chris Flynn, Matthew Kerr, D.R. Lorimer, J.-P. Macquart, Cherry Ng, C. J. Phillips, Danny C. Price, Renée Spiewak

Comments: 9 pages, 4 figures; accepted for publication in ApJL; updated plots, revised scattering analysis

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

[108]  arXiv:1908.10189 (replaced) [pdf, ps, other]

Title: MeV-scale reheating temperature and thermalization of oscillating neutrinos by radiative and hadronic decays of massive particles

Authors: Takuya Hasegawa, Nagisa Hiroshima, Kazunori Kohri, Rasmus S. L. Hansen, Thomas Tram, Steen Hannestad

Comments: 37 pages, 13 figures, to appear in JCAP

Journal-ref: JCAP12(2019)012

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

[109]  arXiv:1909.02018 (replaced) [pdf, other]

Title: Gravitational Waves as a Probe of Left-Right Symmetry Breaking

Authors: Vedran Brdar, Lukas Graf, Alexander J. Helmboldt, Xun-Jie Xu

Comments: 21 pages, 3 figures

Journal-ref: JCAP12(2019)027

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

[110]  arXiv:1909.03233 (replaced) [pdf, other]

Title: 2.5-D retrieval of atmospheric properties from exoplanet phase curves: Application to WASP-43b observations

Authors: Patrick G.J. Irwin, Vivien Parmentier, Jake Taylor, Jo Barstow, Suzanne Aigrain, Graham K.H. Lee, Ryan Garland

Comments: Submitted to M.N.R.A.S. Revised Submission 9th December 2019

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

[111]  arXiv:1909.07995 (replaced) [pdf, other]

Title: Explaining the ANITA events by a $L_e-L_τ$ gauge model

Authors: Arman Esmaili, Yasaman Farzan

Comments: 17 pages, 4 figures; v2: discussion on production mechanism expanded, matches the published version

Journal-ref: JCAP12(2019)017

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

[112]  arXiv:1910.00597 (replaced) [pdf, other]

Title: The Mass-Metallicity and the Fundamental Metallicity Relation revisited on a fully Te-based abundance scale for galaxies

Authors: Mirko Curti, Filippo Mannucci, Giovanni Cresci, Roberto Maiolino

Comments: 21 pages, 13 figures. Accepted for publication on MNRAS. V2: Equation (3) corrected

Journal-ref: MNRAS 491, 944-964 (2020)

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

[113]  arXiv:1910.02108 (replaced) [pdf, other]

Title: Propagation of Alfvén waves in the expanding solar wind with the fast-slow stream interaction

Authors: Chen Shi, Marco Velli, Anna Tenerani, Franco Rappazzo, Victor Réville

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

[114]  arXiv:1910.03488 (replaced) [pdf, other]

Title: Higgs inflation and teleparallel gravity

Authors: Sami Raatikainen, Syksy Rasanen

Comments: 15+12 pages, no figures. v2. Fixed two typos, added and removed a reference

Journal-ref: JCAP12(2019)021

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

[115]  arXiv:1910.05735 (replaced) [pdf, ps, other]

Title: Statistical Mechanics of Gravitational Systems with Regular Orbits: Rigid Body Model of Vector Resonant Relaxation

Authors: Zacharias Roupas

Comments: Minor revision to match published version in Journal of Physics A

Subjects: Astrophysics of Galaxies (astro-ph.GA); Statistical Mechanics (cond-mat.stat-mech); General Relativity and Quantum Cosmology (gr-qc)

[116]  arXiv:1910.06034 (replaced) [pdf, other]

Title: Tidal flows with convection: frequency-dependence of the effective viscosity and evidence for anti-dissipation

Authors: Craig D. Duguid, Adrian J. Barker, Chris A. Jones

Comments: Accepted for publication in MNRAS on 11th October 2019

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

[117]  arXiv:1910.07835 (replaced) [pdf, other]

Title: Determining the mass of the planetary candidate HD 114762 b using Gaia

Authors: Flavien Kiefer

Comments: 4 figure, 4 tables, accepted for publication in A&A on 13/11/2019

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

[118]  arXiv:1910.08431 (replaced) [pdf, ps, other]

Title: Monte-Carlo simulations of relativistic radiation mediated shocks: II. photon starved regime

Authors: Hirotaka Ito, Amir Levinson, Shigehiro Nagataki

Comments: 12 pages, 11 figures, submitted to MNRAS

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

[119]  arXiv:1910.10740 (replaced) [pdf, other]

Title: On the Rate of Neutron Star Binary Mergers from Globular Clusters

Authors: Claire S. Ye (Northwestern/CIERA), Wen-fai Fong, Kyle Kremer, Carl L. Rodriguez, Sourav Chatterjee, Giacomo Fragione, Frederic A. Rasio

Comments: 17 pages, 4 figures, 2 tables, accepted by ApJL

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

[120]  arXiv:1910.12808 (replaced) [pdf, other]

Title: Modelling X-ray RMS spectra I: intrinsically variable AGN

Authors: M. L. Parker, W. N. Alston, Z. Igo, A. C. Fabian

Comments: 8 pages, 4 figures, accepted for publication in MNRAS. Updated to accepted version

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

[121]  arXiv:1910.13451 (replaced) [pdf, other]

Title: The KLEVER Survey: Spatially resolved metallicity maps and gradients in a sample of 1.2 < z < 2.5 lensed galaxies

Authors: Mirko Curti, Roberto Maiolino, Michele Cirasuolo, Filippo Mannucci, Rebecca J. Williams, Matt Auger, Amata Mercurio, Connor Hayden-Pawson, Giovanni Cresci, Alessandro Marconi, Francesco Belfiore, Michele Cappellari, Claudia Cicone, Fergus Cullen, Massimo Meneghetti, Kazuaki Ota, Yingjie Peng, Max Pettini, Mark Swinbank, Paulina Troncoso

Comments: Main text: 23 pages, 11 figures. Appendix: 12 pages, 11 figures. Accepted for publication on MNRAS

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

[122]  arXiv:1910.13944 (replaced) [pdf, other]

Title: Inflation model selection revisited after a 1.91% measurement of the Hubble constant

Authors: Rui-Yun Guo, Jing-Fei Zhang, Xin Zhang

Comments: 4 pages, 1 figure

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

[123]  arXiv:1910.14291 (replaced) [pdf, other]

Title: Measurement of Apparent Magnitude and Effective Temperature with Amateur Telescopes

Authors: Kecheng Qian, Jiaqi Shen

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

[124]  arXiv:1911.00057 (replaced) [pdf, ps, other]

Title: Primordial Black Holes from a tiny bump in the Inflaton potential

Authors: Swagat S. Mishra, Varun Sahni

Comments: 29 pages, 12 figures, additional references and discussion, figures updated

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

[125]  arXiv:1911.00581 (replaced) [pdf, other]

Title: SDSS-IV MaNGA: Variations in the N/O -- O/H relation bias metallicity gradient measurements

Authors: Adam L. Schaefer, Christy Tremonti, Francesco Belfiore, Zachary Pace, Matthew A. Bershady, Brett H. Andrews, Niv Drory

Comments: 8 pages, 4 figures. Submitted to ApJL. All comments are welcome

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

[126]  arXiv:1911.06827 (replaced) [pdf, other]

Title: GFiRe: a Gauge Field integrator for Reheating

Authors: Kaloian D. Lozanov, Mustafa A. Amin

Comments: 35 pages, 13 figures; minor changes, submitted to JCAP

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

[127]  arXiv:1911.12302 (replaced) [pdf, ps, other]

Title: Non-negligible Oscillation Effects in the Crustal Geo-neutrino Calculations

Authors: Ran Han, Yu-Feng Li, Xin Mao

Comments: 16 pages, 4 figures, accepted for the publication in PRD

Subjects: Geophysics (physics.geo-ph); Earth and Planetary Astrophysics (astro-ph.EP); High Energy Physics - Phenomenology (hep-ph)

[128]  arXiv:1911.12418 (replaced) [pdf, other]

Title: QUBIC: using NbSi TESs with a bolometric interferometer to characterize the polarisation of the CMB

Authors: M. Piat, B. Bélier, L. Bergé, N. Bleurvacq, C. Chapron, S. Dheilly, L. Dumoulin, M. González, L. Grandsire, J.-Ch. Hamilton, S. Henrot-Versillé, D.T. Hoang, S. Marnieros, W. Marty, L. Montier, E. Olivieri, C. Oriol, C. Perbost, D. Prêle, D. Rambaud, M. Salatino, G. Stankowiak, J.-P. Thermeau, S. Torchinsky, F. Voisin, P. Ade, J.G. Alberro, A. Almela, G. Amico, L. H. Arnaldi, D. Auguste, J. Aumont, S. Azzoni, S. Banfi, P. Battaglia, E.S. Battistelli, A. Baù, D. Bennett, J.-Ph. Bernard, M. Bersanelli, M.-A. Bigot-Sazy, J. Bonaparte, J. Bonis, A. Bottani, E. Bunn, D. Burke, D. Buzi, A. Buzzelli, F. Cavaliere, P. Chanial, R. Charlassier, F. Columbro, G. Coppi, A. Coppolecchia, G. D'Alessandro, P. de Bernardis, G. De Gasperis, M. De Leo, M. De Petris, A. Di Donato, et al. (78 additional authors not shown)

Comments: Conference proceedings submitted to the Journal of Low Temperature Physics for LTD18

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

[129]  arXiv:1912.00616 (replaced) [pdf, other]

Title: Revisiting pre-inflationary universe of family of $α-$attractor in loop quantum cosmology

Authors: M. Shahalam, Mudhahir Al Ajmi, R. Myrzakulov, Anzhong Wang

Comments: 22 pages, 6 caption figures, 4 tables, typos are corrected

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

[130]  arXiv:1912.00885 (replaced) [pdf, other]

Title: Scalar Induced Gravitational Waves in Different Gauges

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

Comments: 2 figures, 8 pages; errors in I(u,v) corrected

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)

[131]  arXiv:1912.01637 (replaced) [pdf]

Title: Collisional disruption of highly porous targets in the strength regime: Effects of mixture

Authors: Yuichi Murakami, Akiko M. Nakamura, Koki Yokoyama, Yusuke Seto, Sunao Hasegawa

Comments: Planetary and Space Science,in press

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

[132]  arXiv:1912.01919 (replaced) [pdf, other]

Title: Superconformal Generalizations of $R^n-φ^p$ Interpolating Inflationary Theories

Authors: Sibel Boran, Emre Onur Kahya, Nese Ozdemir, Mehmet Ozkan, Utku Zorba

Comments: v2., style changed, more discussions on stability, 8 pages, 2 figures

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

[133]  arXiv:1912.02565 (replaced) [pdf, other]

Title: A dusty benchmark brown dwarf near the ice line of HD 72946

Authors: A.-L. Maire, J.-L. Baudino, S. Desidera, S. Messina, W. Brandner, N. Godoy, F. Cantalloube, R. Galicher, M. Bonnefoy, J. Hagelberg, J. Olofsson, O. Absil, G. Chauvin, T. Henning, M. Langlois

Comments: Accepted for publication in A&A, 10 pages, 10 figures, 1 table. Includes language editing. Missing references in Sect. 6 and Appendix E added

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

[134]  arXiv:1912.02941 (replaced) [pdf, other]

Title: Global Simulations of the Vertical Shear Instability with Non-ideal Magnetohydrodynamical Effects

Authors: Can Cui, Xue-Ning Bai

Comments: 18 pages, 15 figures, ApJ submitted

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

[135]  arXiv:1912.03300 (replaced) [pdf, other]

Title: The hadronic interaction model Sibyll 2.3c and extensive air showers

Authors: Ralph Engel, Anatoli Fedynitch, Thomas K. Gaisser, Felix Riehn, Todor Stanev

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

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