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New submissions for Wed, 22 Apr 20

[1]  arXiv:2004.09510 [pdf, other]

Title: The Ultraluminous Lyman Alpha Luminosity Function at z=6.6

Authors: Anthony J. Taylor, Amy J. Barger, Lennox L. Cowie, Esther M. Hu, Antoinette Songaila

Comments: Accepted for publication in ApJ. 12 pages, 8 Figures, 3 Tables

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

We present the luminosity function (LF) for ultraluminous Ly$\alpha$ emitting galaxies (LAEs) at z = 6.6. We define ultraluminous LAEs (ULLAEs) as galaxies with logL(Ly$\alpha$) > 43.5 erg s$^{-1}$. We select our main sample using the g', r', i', z', and NB921 observations of a wide-area (30 deg$^2$) Hyper Suprime-Cam survey of the North Ecliptic Pole (NEP) field. We select candidates with g', r', i' > 26, NB921 $\leq$ 23.5, and NB921 - z' $\leq$ 1.3. Using the DEIMOS spectrograph on Keck II, we confirm 9 of our 14 candidates as ULLAEs at z = 6.6 and the remaining 5 as an AGN at z = 6.6, two [OIII]$\lambda$5007 emitting galaxies at z = 0.84 and z = 0.85, and two non-detections. This emphasizes the need for full spectroscopic follow-up to determine accurate LFs. In constructing the ULLAE LF at z = 6.6, we combine our 9 NEP ULLAEs with two previously discovered and confirmed ULLAEs in the COSMOS field: CR7 and COLA1. We apply rigorous corrections for incompleteness based on simulations. We compare our ULLAE LF at z = 6.6 with LFs at z = 5.7 and z = 6.6 from the literature. Our data reject some previous LF normalizations and power law indices, but they are broadly consistent with others. Indeed, a comparative analysis of the different literature LFs suggests that none is fully consistent with any of the others, making it critical to determine the evolution from z = 5.7 to z = 6.6 using LFs constructed in exactly the same way at both redshifts.

[2]  arXiv:2004.09513 [pdf, other]

Title: PLATON II: New Capabilities And A Comprehensive Retrieval on HD 189733b Transit and Eclipse Data

Authors: Michael Zhang, Yayaati Chachan, Eliza M.-R. Kempton, Heather Knutson, Wenjun (Happy) Chang

Comments: submitted to ApJ

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

Recently, we introduced PLanetary Atmospheric Tool for Observer Noobs (PLATON), a Python package that calculates model transmission spectra for exoplanets and retrieves atmospheric characteristics based on observed spectra. We now expand the capabilities of this package to include the ability to compute secondary eclipse depths. We have also added the option to calculate models using the correlated-k method for radiative transfer, which vastly improves accuracy without sacrificing speed. Additionally, we update the opacities in PLATON--many of which were generated using old or proprietary line lists--using the most recent and complete public line lists. These opacities are made available at R=1000 and R=10,000 over the $0.3-30 \mu m$ range, and at R=375,000 in select near IR bands, making it possible to utilize PLATON for ground-based high resolution cross correlation studies. To demonstrate \platon's new capabilities, we perform a retrieval on published HST and Spitzer transmission and emission spectra of the archetypal hot Jupiter HD 189733b. This is the first joint transit and secondary eclipse retrieval for this planet in the literature, as well as the most comprehensive set of both transit and eclipse data assembled for a retrieval to date. We find that these high signal-to-noise data are well-matched by atmosphere models with a C/O ratio of $0.66_{-0.09}^{+0.05}$ and a metallicity of $12_{-5}^{+8}$ times solar where the terminator is dominated by extended nanometer-sized haze particles at optical wavelengths. These are among the smallest uncertainties reported to date for the atmospheric composition of a transiting gas giant planet. We conclude that we are now operating in a regime where the uncertainty due to our choice of model is larger than the uncertainties associated with the data themselves.

[3]  arXiv:2004.09515 [pdf, other]

Title: The Effective Halo Model: Creating a Physical and Accurate Model of the Matter Power Spectrum and Cluster Counts

Authors: Oliver H. E. Philcox, David N. Spergel, Francisco Villaescusa-Navarro

Comments: 38 pages, 13 figures, submitted to Phys. Rev. D. Python package and tutorial available at this http URL

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Astrophysics of Galaxies (astro-ph.GA); Instrumentation and Methods for Astrophysics (astro-ph.IM); High Energy Physics - Phenomenology (hep-ph); High Energy Physics - Theory (hep-th)

We introduce a physically-motivated model of the matter power spectrum, based on the halo model and perturbation theory. This model achieves 1\% accuracy on all $k-$scales between $k=0.02h\,\mathrm{Mpc}^{-1}$ to $k=1h\,\mathrm{Mpc}^{-1}$. Our key ansatz is that the number density of halos depends on the non-linear density contrast filtered on some unknown scale $R$. Using the Effective Field Theory of Large Scale Structure to evaluate the two-halo term, we obtain a model for the power spectrum with only two fitting parameters: $R$ and the effective `sound speed', which encapsulates small-scale physics. This is tested with two suites of cosmological simulations across a broad range of cosmologies and found to be highly accurate. Due to its physical motivation, the statistics can be easily extended beyond the power spectrum; we additionally derive the one-loop covariance matrices of cluster counts and their combination with the matter power spectrum. This yields a significantly better fit to simulations than previous models, and includes a new model for super-sample effects, which is rigorously tested with separate universe simulations. At low redshift, we find a significant ($\sim 10\%$) exclusion covariance from accounting for the finite size of halos which has not previously been modeled. Such power spectrum and covariance models will enable joint analysis of upcoming large-scale structure surveys, gravitational lensing surveys and cosmic microwave background maps on scales down to the non-linear scale. We provide a publicly released Python code.

[4]  arXiv:2004.09516 [pdf, other]

Title: The CO-dark molecular gas mass in 30 Doradus

Authors: Mélanie Chevance, Suzanne C. Madden, Christian Fischer, William D. Vacca, Vianney Lebouteiller, Dario Fadda, Frédéric Galliano, Remy Indebetouw, J. M. Diederik Kruijssen, Min-Young Lee, Albrecht Poglitsch, Fiorella L. Polles, Diane Cormier, Sacha Hony, Christof Iserlohe, Alfred Krabbe, Margaret Meixner, Elena Sabbi, Hans Zinnecker

Comments: 14 pages, 7 figures. Accepted for publication in MNRAS (April 16, 2020)

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

Determining the efficiency with which gas is converted into stars in galaxies requires an accurate determination of the total reservoir of molecular gas mass. However, despite being the most abundant molecule in the Universe, H$_2$ is challenging to detect through direct observations and indirect methods have to be used to estimate the total molecular gas reservoir. These are often based on scaling relations from tracers such as CO or dust, and are generally calibrated in the Milky Way. Yet, evidence that these scaling relations are environmentally dependent is growing. In particular, the commonly used CO-to-H$_2$ conversion factor (X$_{\rm CO}$) is expected to be higher in metal-poor and/or strongly UV-irradiated environments. We use new SOFIA/FIFI-LS observations of far-infrared fine structure lines from the ionised and neutral gas and the Meudon photodissociation region model to constrain the physical properties and the structure of the gas in the massive star-forming region of 30 Doradus in the Large Magellanic Cloud, and determine the spatially resolved distribution of the total reservoir of molecular gas in the proximity of the young massive cluster R136. We compare this value with the molecular gas mass inferred from ground-based CO observations and dust-based estimates to quantify the impact of this extreme environment on commonly used tracers of the molecular gas. We find that the strong radiation field combined with the half-solar metallicity of the surrounding gas are responsible for a large reservoir of "CO-dark" molecular gas, leaving a large fraction of the total H$_2$ gas (> 75%) undetected when adopting a standard X$_{\rm CO}$ factor in this massive star-forming region.

[5]  arXiv:2004.09518 [pdf, other]

Title: Detecting the Cosmic Web: Lyα Emission from Simulated Filaments at z=3

Authors: Lydia M. Elias, Shy Genel, Amiel Sternberg, Julien Devriendt, Adrianne Slyz, Eli Visbal, Nicolas Bouché

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

The standard cosmological model ($\Lambda$CDM) predicts the existence of the cosmic web: a distribution of matter into sheets and filaments connecting massive halos. However, observational evidence has been elusive due to the low surface brightness of the filaments. Recent deep MUSE/VLT data and upcoming observations offer a promising avenue for Ly$\alpha$ detection, motivating the development of modern theoretical predictions. We use hydrodynamical cosmological simulations run with the AREPO code to investigate the potential detectability of large-scale filaments, excluding contributions from the halos embedded in them. We focus on filaments connecting massive ($M_{200c}\sim(1-3)\times10^{12} M_\odot$) halos at z=3, and compare different simulation resolutions, feedback levels, and mock-image pixel sizes. We find increasing simulation resolution does not substantially improve detectability notwithstanding the intrinsic enhancement of internal filament structure. By contrast, for a MUSE integration of 31 hours, including feedback increases the detectable area by a factor of $\simeq$5.5 on average compared with simulations without feedback, implying that even the non-bound components of the filaments have substantial sensitivity to feedback. Degrading the image resolution from the native MUSE scale of (0.2")$^2$ per pixel to (5.3")$^2$ apertures has the strongest effect, increasing the detectable area by a median factor of $\simeq$200 and is most effective when the size of the pixel roughly matches the width of the filament. Finally, we find the majority of Ly$\alpha$ emission is due to electron impact collisional excitations, as opposed to radiative recombination.

[6]  arXiv:2004.09519 [pdf, other]

Title: Blasts from the Past: Supernova Shock Breakouts among X-Ray Transients in the XMM-Newton Archive

Authors: Dennis Alp, Josefin Larsson

Comments: 29 pages, 1 figure, 7 tables, 12 SN SBO candidates. Submitted to ApJ

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

The first electromagnetic signal from a supernova (SN) is released when the shock crosses the progenitor surface. This shock breakout (SBO) emission provides constraints on progenitor and explosion properties. Observationally, SBOs appear as minute to hour-long extragalactic X-ray transients. They are challenging to detect and only one SBO has been observed to date. Here, we search the XMM-Newton archive and find twelve new SN SBO candidates. We identify host galaxies to nine of these at estimated redshifts of 0.1-1. The SBO candidates have energies of ${\sim}10^{46}$ erg, timescales of 30-3000 s, and temperatures of 0.1-1 keV. They are all consistent with being SN SBOs, but some may be misidentified Galactic foreground sources or other extragalactic objects. SBOs from blue supergiants agree well with most of the candidates. However, a few could be SBOs from Wolf-Rayet stars surrounded by dense circumstellar media, whereas two are more naturally explained as SBOs from red supergiants. The observations tentatively support asymmetric SBOs, in agreement with recent three-dimensional SN explosion simulations. eROSITA may detect ${\sim}$2 SBOs per year, which could be detected in live analyses and promptly followed-up.

[7]  arXiv:2004.09520 [pdf, other]

Title: Testing gravity theories with cosmic microwave background in the degenerate higher-order scalar-tensor theory

Authors: Takashi Hiramatsu, Daisuke Yamauchi

Comments: 19 pages, 5 figures, 1 table

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

We study the cosmic microwave background (CMB) in the framework of the degenerate higher-order scalar-tensor (DHOST) theory to test gravity theories. This theoretical framework includes the wide class of dark energy models such as the Horndeski theory and its extensions as certain limits, and the general relativity can be also recovered. In this study, to test gravity theories with CMB, we formulate the linear perturbations of gravity and matter in the theory and their effective description parameterised by time-dependent effective field theory (EFT) parameters, $\alpha_i$ $(i=B,K,T,M,H,L)$ and $\beta_i$ $(i=1,2,3)$. Based on the resultant DHOST framework, we develop a numerical code to solve Boltzmann equations consistently. We then show that the angular power spectra of the CMB temperature anisotropies, E-mode and lensing potential as a demonstration and find that the parameter characterising the DHOST theory, $\beta_1$, provides the larger modifications of the spectra, compared with other EFT parameters. We also show the results in the case of a specific model in which the cosmic expansion as well as the EFT parameters are consistently determined.

[8]  arXiv:2004.09525 [pdf, other]

Title: Binary black holes in young star clusters: the impact of metallicity

Authors: Ugo N. Di Carlo, Michela Mapelli, Nicola Giacobbo, Mario Spera, Yann Bouffanais, Sara Rastello, Filippo Santoliquido, Mario Pasquato, Alessandro Ballone, Alessandro A. Trani, Stefano Torniamenti, Francesco Haardt

Comments: 13 pages, 9 figures, 5 tables, to be submitted to MNRAS. Comments welcome

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

Young star clusters are the most common birth-place of massive stars and are dynamically active environments. Here, we study the formation of black holes (BHs) and binary black holes (BBHs) in young star clusters, by means of 6000 N-body simulations coupled with binary population synthesis. We probe three different stellar metallicities (Z=0.02, 0.002 and 0.0002) and two initial density regimes (density at the half-mass radius $\rho_{\rm h}\ge{}3.4\times10^4$ and $\ge{1.5\times10^2}$ M$_\odot$ pc$^{-3}$ in dense and loose star clusters, respectively). Metal-poor clusters tend to form more massive BHs than metal-rich ones. We find $\sim{}6$, $\sim{}2$, and $<1$% of BHs with mass $m_{\rm BH}>60$ M$_\odot$ at Z=0.0002, 0.002 and 0.02, respectively. In metal-poor clusters, we form intermediate-mass BHs with mass up to $\sim{}320$ M$_\odot$. BBH mergers born via dynamical exchanges (exchanged BBHs) can be more massive than BBH mergers formed from binary evolution: the former (latter) reach total mass up to $\sim{}140$ M$_\odot$ ($\sim{}80$ M$_\odot$). The most massive BBH merger in our simulations has primary mass $\sim{}88$ M$_\odot$, inside the pair-instability mass gap, and a mass ratio of $\sim{}0.5$. Only BBHs born in young star clusters from metal-poor progenitors can match the masses of GW170729, the most massive event in O1 and O2, and those of GW190412, the first unequal-mass merger. We estimate a local BBH merger rate density $\sim{}110$ and $\sim{}55$ Gpc$^{-3}$ yr$^{-1}$, if we assume that all stars form in loose and dense star clusters, respectively.

[9]  arXiv:2004.09528 [pdf, other]

Title: Warm dust in high-z galaxies: origin and implications

Authors: L. Sommovigo, A. Ferrara, A. Pallottini, S. Carniani, S. Gallerani, D. Decataldo

Comments: 14 pages, 6 figures, submitted to MNRAS

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

ALMA observations have revealed the presence of dust in galaxies in the Epoch of Reionization (redshift $z>6$). However, the dust temperature, $T_d$, remains unconstrained, and this introduces large uncertainties, particularly in the dust mass determinations. Using an analytical and physically-motivated model, we show that dust in high-$z$, star-forming giant molecular clouds (GMC), largely dominating the observed far-infrared luminosity, is warmer ($T_d > 60\ \mathrm{K}$) than locally. This is due to the more compact GMC structure induced by the higher gas pressure and turbulence characterizing early galaxies. The compactness also delays GMC dispersal by stellar feedback, thus $\sim 40\%$ of the total UV radiation emitted by newly born stars remains obscured. A higher $T_d$ has additional implications: it (a) reduces the tension between local and high-$z$ IRX-$\beta$ relation, (b) alleviates the problem of the uncomfortably large dust masses deduced from observations of some EoR galaxies.

[10]  arXiv:2004.09530 [pdf, other]

Title: EDGE: From quiescent to gas-rich to star-forming low-mass dwarf galaxies

Authors: Martin P. Rey, Andrew Pontzen, Oscar Agertz, Matthew D. A. Orkney, Justin I. Read, Joakim Rosdahl

Comments: 14 pages, submitted to MNRAS

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

We study how star formation is regulated in low-mass field dwarf galaxies ($10^5 \leq M_{\star} \leq 10^6 \, \text{M}_{\odot}$), using cosmological high-resolution ($3 \, \text{pc}$) hydrodynamical simulations. Cosmic reionization quenches star formation in all our simulated dwarfs, but three galaxies with final dynamical masses of $3 \times 10^{9} \,\text{M}_{\odot}$ are subsequently able to replenish their interstellar medium by slowly accreting gas. Two of these galaxies re-ignite and sustain star formation until the present day at an average rate of $10^{-5} \, \text{M}_{\odot} \, \text{yr}^{-1}$, highly reminiscent of observed low-mass star-forming dwarf irregulars such as Leo T. The resumption of star formation is delayed by several billion years due to residual feedback from stellar winds and Type Ia supernovae; even at $z=0$, the third galaxy remains in a temporary equilibrium with a large gas content but without any ongoing star formation. Using the "genetic modification'' approach, we create an alternative mass growth history for this gas-rich quiescent dwarf and show how a small $(0.2\,\mathrm{dex})$ increase in dynamical mass can overcome residual stellar feedback, re-igniting star formation. The interaction between feedback and mass build-up produces a diversity in the stellar ages and gas content of low-mass dwarfs, which will be probed by combining next-generation HI and imaging surveys.

[11]  arXiv:2004.09532 [pdf, other]

Title: ALMA Observations of Massive Clouds in the Central Molecular Zone: Jeans Fragmentation and Cluster Formation

Authors: Xing Lu, Yu Cheng, Adam Ginsburg, Steven N. Longmore, J. M. Diederik Kruijssen, Cara Battersby, Qizhou Zhang, Daniel L. Walker

Comments: ApJ Letters accepted. A full catalog of the identified cores is available as a machine-readable table (this https URL)

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

We report ALMA Band 6 continuum observations of 2000 AU resolution toward four massive molecular clouds in the Central Molecular Zone of the Galaxy. To study gas fragmentation, we use the dendrogram method to identify cores as traced by the dust continuum emission. The four clouds exhibit different fragmentation states at the observed resolution despite having similar masses at the cloud scale ($\sim$1--5 pc). Assuming a constant dust temperature of 20 K, we construct core mass functions of the clouds and find a slightly top-heavy shape as compared to the canonical initial mass function, but we note several significant uncertainties that may affect this result. The characteristic spatial separation between the cores as identified by the minimum spanning tree method, $\sim$$10^4$ AU, and the characteristic core mass, 1--7 $M_\odot$, are consistent with predictions of thermal Jeans fragmentation. The three clouds showing fragmentation may be forming OB associations (stellar mass $\sim$$10^3$ $M_\odot$). None of the four clouds under investigation seem to be currently able to form massive star clusters like the Arches and the Quintuplet ($\sim$$10^4$ $M_\odot$), but they may form such clusters by further gas accretion onto the cores.

[12]  arXiv:2004.09533 [pdf, other]

Title: The cosmic merger rate density evolution of compact binaries formed in young star clusters and in isolated binaries

Authors: Filippo Santoliquido, Michela Mapelli, Yann Bouffanais, Nicola Giacobbo, Ugo N. Di Carlo, Sara Rastello, M. Celeste Artale, Alessandro Ballone

Comments: 11 pages, 5 figures, 1 table, to be submitted to ApJ. Comments welcome

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

Next generation ground-based gravitational-wave detectors will observe binary black hole (BBH) mergers up to redshift $\gtrsim{}10$, probing the evolution of compact binary (CB) mergers across cosmic time. Here, we present a new data-driven model to estimate the cosmic merger rate density (MRD) evolution of CBs, by coupling catalogs of CB mergers with observational constraints on the cosmic star formation rate density and on the metallicity evolution of the Universe. We adopt catalogs of CB mergers derived from recent $N-$body and population-synthesis simulations, to describe the MRD of CBs formed in young star clusters (hereafter, dynamical CBs) and in the field (hereafter, isolated CBs). The local MRD of dynamical BBHs is $\mathcal{R}_{\rm BBH}=67^{+29}_{-23}$ Gpc$^{-3}$ yr$^{-1}$, consistent with the 90% credible interval from the first and second observing run (O1 and O2) of the LIGO-Virgo collaboration, and with the local MRD of isolated BBHs ($\mathcal{R}_{\rm BBH}=49^{+79}_{-37}$ Gpc$^{-3}$ yr$^{-1}$). The local MRD of dynamical and isolated black hole-neutron star binaries (BHNSs) is $\mathcal{R}_{\rm BHNS}=38^{+32}_{-24}$ and $45^{+45}_{-32}$ Gpc$^{-3}$ yr$^{-1}$, respectively. Both values are consistent with the upper limit inferred from O1 and O2. Finally, the local MRD of dynamical binary neutron stars (BNSs, $\mathcal{R}_{\rm BNS}=150^{+56}_{-40}$ Gpc$^{-3}$ yr$^{-1}$) is a factor of two lower than the local MRD of BNSs formed in isolated binaries ($\mathcal{R}_{\rm BNS}=281^{+109}_{-75}$ Gpc$^{-3}$ yr$^{-1}$). The MRD for all CB classes grows with redshift, reaching its maximum at $z \in [1.5,2.5]$, and then decreases. This trend springs from the interplay between cosmic star formation rate, metallicity evolution and delay time of binary compact objects.

[13]  arXiv:2004.09534 [pdf, other]

Title: VV 655 and NGC 4418: Implications of an interaction for the evolution of a LIRG

Authors: Erin Boettcher, John S. Gallagher III, Youichi Ohyama, Eskil Varenius, Susanne Aalto, Niklas Falstad, Sabine König, Kazushi Sakamoto, Tova M. Yoast-Hull

Comments: 9 pages, 4 figures, accepted for publication in Astronomy & Astrophysics

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

VV 655, a dwarf irregular galaxy with HI tidal debris, is a companion to the lenticular luminous infrared galaxy (LIRG) NGC 4418. NGC 4418 stands out among nearby LIRGs due to its dense central concentration of molecular gas and the dusty, bi-polar structures along its minor axis suggestive of a wind driven by a central starburst and possible nuclear activity. We seek to understand the consequences of the ongoing minor interaction between VV 655 and NGC 4418 for the evolution of the LIRG, including the origin of the gas supply responsible for its unusual nuclear properties. We investigate the structural, kinematic, and chemical properties of VV 655 and NGC 4418 by analyzing archival imaging data and optical spectroscopic observations from the SDSS-III and new spectra from SALT-RSS. We characterize their gas-phase metal abundances and spatially resolved, ionized gas kinematics, and demonstrate that the gas-phase metallicity in NGC 4418 significantly exceeds that in VV 655. No kinematic disturbances in the ionized gas are observed along the minor axis of NGC 4418, but we see evidence for ionized gas outflows from VV 655 that may increase the cross-section for gas stripping in grazing collisions. A faint, asymmetric outer arm is detected in NGC 4418 of the type normally associated with galaxy-galaxy interactions. The simplest model suggests that the minor interaction between VV 655 and NGC 4418 produced the unusual nuclear properties of the LIRG via tidal torquing of the interstellar medium of NGC 4418 rather than through a significant gas transfer event. In addition to inducing a central concentration of gas in NGC 4418, this interaction also produced an enhanced star formation rate and an outer tidal arm in the LIRG. The VV 655-NGC 4418 system offers an example of the potential for minor collisions to alter the evolutionary pathways of giant galaxies.

[14]  arXiv:2004.09535 [pdf, other]

Title: NIHAO XXIV: Rotation or pressure supported systems? Simulated Ultra Diffuse Galaxies show a broad distribution in their stellar kinematics

Authors: Salvador Cardona-Barrero, Arianna Di Cintio, Christopher B. A. Brook, Tomas Ruiz-Lara, Michael A. Beasley, Jesus Falcón-Barroso, Andrea V. Macciò

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

In recent years a new window on galaxy evolution opened, thanks to the increasing discovery of galaxies with a low surface brightness, such as Ultra Diffuse Galaxies (UDGs). The formation mechanism of these systems is still a much debated question, and so are their kinematical properties. In this work, we address this topic by analyzing the stellar kinematics of isolated UDGs formed in the hydrodynamical simulation suite NIHAO. We construct projected line-of-sight velocity and velocity dispersion maps to compute the projected specific angular momentum, $\lambda_{\rm R}$, to characterize the kinematical support of the stars in these galaxies. We found that UDGs cover a broad distribution, ranging from dispersion to rotation supported galaxies, with similar abundances in both regimes. The degree of rotation support of simulated UDGs correlates with several properties such as galaxy morphology, higher HI fractions and larger effective radii with respect to the dispersion supported group, while the dark matter halo spin and mass accretion history are similar amongst the two populations. We demonstrate that the alignment of the infalling baryons into the protogalaxy at early $z$ is the principal driver of the $z$=0 stellar kinematic state: pressure supported isolated UDGs form via mis-aligned gas accretion while rotation supported ones build-up their baryons in an ordered manner. Accounting for random inclination effects, we predict that a comprehensive survey will find nearly half of field UDGs to have rotationally supported stellar disks.

[15]  arXiv:2004.09540 [pdf, other]

Title: A kinematic view of NGC 1261: structural parameters, internal dispersion, absolute proper motion and Blue Straggler Stars

Authors: S. Raso, M. Libralato, A. Bellini, F. R. Ferraro, B. Lanzoni, M. Cadelano, C. Pallanca, E. Dalessandro, G. Piotto, J. Anderson, S. T. Sohn

Comments: 19 pages, 12 figures, 2 tables; accepted for publication in ApJ

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

We constructed a Hubble Space Telescope (HST) astro-photometric catalog of the central region of the Galactic globular cluster NGC 1261. This catalog, complemented with Gaia DR2 data sampling the external regions, has been used to estimate the structural parameters of the system (i.e., core, half-mass, tidal radii and concentration) from its resolved star density profile. We computed high-precision proper motions thanks to multi-epoch HST data and derived the cluster velocity dispersion profile in the plane of the sky for the innermost region, finding that the system is isotropic. The combination with line-of-sight information collected from spectroscopy in the external regions provided us with the cluster velocity dispersion profile along the entire radial extension. We also measured the absolute proper motion of NGC 1261 using a few background galaxies as a reference. The radial distribution of the Blue Straggler Star population shows that the cluster is in a low/intermediate phase of dynamical evolution.

[16]  arXiv:2004.09541 [pdf, other]

Title: Spectral Modification of Magnetar Flares by Resonant Cyclotron Scattering

Authors: Shotaro Yamasaki, Yuri Lyubarsky, Jonathan Granot, Ersin Gogus

Comments: 10 pages, 6 figures, submitted to MNRAS

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

Spectral modification of energetic magnetar flares by resonant cyclotron scattering (RCS) is considered. During energetic flares, photons emitted from the magnetically-trapped fireball near the stellar surface should resonantly interact with magnetospheric electrons or positrons. We show by a simple thought experiment that such scattering particles are expected to move at mildly relativistic speeds along closed magnetic field lines, which would slightly shift the incident photon energy due to the Doppler effect. We develop a toy model for the spectral modification by a single RCS that incorporates both a realistic seed photon spectrum from the trapped fireball and the velocity field of particles, which is unique to the flaring magnetosphere. We show that our spectral model can be effectively characterized by a single parameter; the effective temperature of the fireball, which enables us to fit observed spectra with low computational cost. We demonstrate that our single scattering model is in remarkable agreement with Swift/BAT data of intermediate flares from SGR 1900+14, corresponding to effective fireball temperatures of $T_{\rm eff}=6$-$7$ keV, whereas BeppoSAX/GRBM data of giant flares from the same source may need more elaborate models including the effect of multiple scatterings. Nevertheless, since there is no standard physically-motivated model for magnetar flare spectra, our model could be a useful tool to study magnetar bursts, shedding light on the hidden properties of the flaring magnetosphere.

[17]  arXiv:2004.09542 [pdf, other]

Title: Propagating sample variance uncertainties in redshift calibration: simulations, theory and application to the COSMOS2015 data

Authors: Carles Sánchez, Marco Raveri, Alex Alarcon, Gary M. Bernstein

Comments: 18 pages, 16 figures. Comments welcome

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

Cosmological analyses of galaxy surveys rely on knowledge of the redshift distribution of their galaxy sample. This is usually derived from a spectroscopic and/or many-band photometric calibrator survey of a small patch of sky. The uncertainties in the redshift distribution of the calibrator sample include a contribution from shot noise, or Poisson sampling errors, but, given the small volume they probe, they are dominated by sample variance introduced by large-scale structures. Redshift uncertainties have been shown to constitute one of the leading contributions to systematic uncertainties in cosmological inferences from weak lensing and galaxy clustering, and hence they must be propagated through the analyses. In this work, we study the effects of sample variance on small-area redshift surveys, from theory to simulations to the COSMOS2015 data set. We present a three-step Dirichlet method of resampling a given survey-based redshift calibration distribution to enable the propagation of both shot noise and sample variance uncertainties. The method can accommodate different levels of prior confidence on different redshift sources. This method can be applied to any calibration sample with known redshifts and phenotypes (i.e. cells in a self-organizing map, or some other way of discretizing photometric space), and provides a simple way of propagating prior redshift uncertainties into cosmological analyses. As a worked example, we apply the full scheme to the COSMOS2015 data set, for which we also present a new, principled SOM algorithm designed to handle noisy photometric data. We make available a catalog of the resulting resamplings of the COSMOS2015 galaxies.

[18]  arXiv:2004.09555 [pdf, other]

Title: The MUSTANG-2 Galactic Plane Survey (MGPS90) pilot

Authors: Adam Ginsburg, L. D. Anderson, Simon Dicker, Charles Romero, Brian Svoboda, Mark Devlin, Roberto Galván-Madrid, Remy Indebetouw, Hauyu Baobab Liu, Brian Mason, Tony Mroczkowski, W. P. Armentrout, John Bally, Crystal Brogan, Natalie Butterfield, Todd R. Hunter, Erik D. Reese, Erik Rosolowsky, Craig Sarazin, Yancy Shirley, Jonathan Sievers, Sara Stanchfield

Comments: Accepted to ApJS. Data publicly released, with links in paper

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

We report the results of a pilot program for a Green Bank Telescope (GBT) MUSTANG Galactic Plane survey at 3 mm (90 GHz), MGPS90. The survey achieves a typical $1\sigma$ depth of $1-2$ mJy beam$^{-1}$ with a 9" beam. We describe the survey parameters, quality assessment process, cataloging, and comparison with other data sets. We have identified 709 sources over seven observed fields selecting some of the most prominent millimeter-bright regions between $0\deg < \ell < 50\deg$ (total area $\approx 7.5 \deg^2$). The majority of these sources have counterparts at other wavelengths. By applying flux selection criteria to these sources, we successfully recovered several known hypercompact HII (HCHII) regions, but did not confirm any new ones. We identify 126 sources that have mm-wavelength counterparts but do not have cm-wavelength counterparts and are therefore candidate HCHII regions; of these, 10 are morphologically compact and are strong candidates for new HCHII regions. Given the limited number of candidates in the extended area in this survey compared to the relatively large numbers seen in protoclusters W51 and W49, it appears that most HCHII regions exist within dense protoclusters. Comparing the counts of HCHII to ultracompact HII (UCHII) regions, we infer the HCHII region lifetime is 16-46% that of the UCHII region lifetime. We additionally separated the 3 mm emission into dust and free-free emission by comparing with archival 870 $\mu$m and 20 cm data. In the selected pilot fields, most ($\gtrsim80$%) of the 3 mm emission comes from plasma, either through free-free or synchrotron emission.

[19]  arXiv:2004.09566 [pdf, other]

Title: Towards a unified equation of state for multi-messenger astronomy

Authors: Michał Marczenko, David Blaschke, Krzysztof Redlich, Chihiro Sasaki

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

A first step in developing a benchmark equation of state (EoS) model for multi-messenger astronomy is presented that unifies the thermodynamics of quark and hadronic degrees of freedom. A Lagrangian approach to the thermodynamic potential of quark-meson-nucleon (QMN) matter is used where dynamical chiral-symmetry breaking is described by the scalar mean-field dynamics coupled to quarks as well as to nucleons and their chiral partners, whereby its restoration occurs in the hadronic phase by parity doubling as well as in the quark phase. Quark confinement is achieved by an auxiliary scalar field that parametrizes a dynamical infrared cutoff in the quark sector, serving as an ultraviolet cutoff for the nucleonic phase-space. The gap equations are solved for the isospin-symmetric case as well as for neutron star (NS) conditions. The mass-radius (MR) relation of NSs and their tidal deformability (TD) parameter are calculated. The obtained EoS is in accordance with nuclear matter properties at saturation density and with the flow constraint from heavy ion collision experiments. For isospin-asymmetric matter a sequential occurrence of light quark flavors is obtained, allowing for a mixed phase of chirally-symmetric nucleonic matter with deconfined down quarks. The MR relations and TDs for compact stars fulfill the constraints from latest astrophysical observations for PSR J0740+6620, PSR J0030+0451, and the NS merger GW170817, whereby the tension between the maximum mass and compactness constraints rather uniquely fixes the model parameters. The model predicts the existence of stars with a core of chirally restored but purely hadronic (confined) matter for masses beyond $1.8~M_\odot$. Stars with pure-quark matter cores are found to be unstable against the gravitational collapse. This instability is shifted still to higher densities if repulsive interactions between quarks are included.

[20]  arXiv:2004.09567 [pdf, other]

Title: Turbulence and Energetic Particles in Radiative Shock Waves in the Cygnus Loop I: Shock Properties

Authors: John C. Raymond, Igor V. Chilingarian, William P. Blair, Ravi Sankrit, Jonathan D. Slavin, Blakesley Burkhart

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

We have obtained a contiguous set of long-slit spectra of a shock wave in the Cygnus Loop to investigate its structure, which is far from the morphology predicted by 1D models. Proper motions from Hubble Space Telescope images combined with the known distance to the Cygnus Loop provide an accurate shock speed. Earlier analyses of shock spectra estimated the shock speed, postshock density, temperature, and elemental abundances. In this paper we determine several more shock parameters: a more accurate shock speed, ram pressure, density, compression ratio, dust destruction efficiency, magnetic field strength, and vorticity in the cooling region. From the derived shock properties we estimate the emissivities of synchrotron emission in the radio and pion decay emission in the gamma rays. Both are consistent with the observations if we assume simple adiabatic compression of ambient cosmic rays as in the van der Laan mechanism. We also find that, although the morphology is far from that predicted by 1D models and the line ratios vary dramatically from point to point, the average spectrum is matched reasonably well by 1D shock models with the shock speed derived from the measured proper motion. A subsequent paper will analyze the development of turbulence in the cooling zone behind the shock.

[21]  arXiv:2004.09572 [pdf, other]

Title: Dark Matter properties through cosmic history

Authors: Stéphane Ilić, Michael Kopp, Constantinos Skordis, Daniel B. Thomas

Comments: 20 pages, 10 figures, 5 tables

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

We perform the first test of Dark Matter (DM) stress-energy evolution through cosmic history, using Cosmic Microwave Background measurements supplemented with Baryon Acoustic Oscillation data and the Hubble Space Telescope key project data. We constrain the DM equation of state (EoS) in 8 redshift bins, and its sound speed and (shear) viscosity in 9 redshift bins, finding no convincing evidence for non-$\Lambda$CDM values in any of the redshift bins. Despite this enlarged parameter space, the sound speed and viscosity are constrained relatively well at late times (due to the inclusion of CMB lensing), whereas the EoS is most strongly constrained around recombination. These results constrain for the first time the level of ''coldness'' required of DM across various cosmological epochs at both the background and perturbative levels. We show that simultaneously allowing time dependence for both the EoS and sound speed parameters shifts the posterior of the DM abundance before recombination to a higher value, whilst keeping the present day DM abundance similar to the $\Lambda$CDM value. This shifts the posterior for the present day Hubble constant compared to $\Lambda$CDM, suggesting that DM with time-dependent parameters is well-suited to explore possible solutions to persistent tensions within the $\Lambda$CDM model.

[22]  arXiv:2004.09586 [pdf, other]

Title: Unusually High CO Abundance of the First Active Interstellar Comet

Authors: Cordiner, M. A., Milam, S. N., Biver, N., Bockelée-Morvan, D., Roth, N. X., Bergin, E. A., Jehin, E., Remijan, A. J., Charnley, S. B., Mumma, M. J., Boissier, J., Crovisier, J., Paganini, L., Kuan, Y.-J., Lis, D. C

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

Comets spend most of their lives at large distances from any star, during which time their interior compositions remain relatively unaltered. Cometary observations can therefore provide direct insight into the chemistry that occurred during their birth at the time of planet formation. To-date, there have been no confirmed observations of parent volatiles (gases released directly from the nucleus) of a comet from any planetary system other than our own. Here we present high-resolution, interferometric observations of 2I/Borisov, the first confirmed interstellar comet, obtained using the Atacama Large Millimeter/submillimeter Array (ALMA) on 15th-16th December 2019. Our observations reveal emission from hydrogen cyanide (HCN), and carbon monoxide (CO), coincident with the expected position of 2I/Borisov's nucleus, with production rates Q(HCN)=$(7.0\pm1.1)\times10^{23}$ s$^{-1}$ and Q(CO)=$(4.4\pm0.7)\times10^{26}$ s$^{-1}$. While the HCN abundance relative to water (0.06-0.16%) appears similar to that of typical, previously observed comets in our Solar System, the abundance of CO (35-105%) is among the highest observed in any comet within 2~au of the Sun. This shows that 2I/Borisov must have formed in a relatively CO-rich environment - probably beyond the CO ice-line in the very cold, outer regions of a distant protoplanetary accretion disk, as part of a population of small, icy bodies analogous to our Solar System's own proto-Kuiper Belt.

[23]  arXiv:2004.09597 [pdf, other]

Title: Keck/NIRC2 $L$'-Band Imaging of Jovian-Mass Accreting Protoplanets around PDS 70

Authors: Jason J. Wang, Sivan Ginzburg, Bin Ren, Nicole Wallack, Peter Gao, Dimitri Mawet, Charlotte Z. Bond, Sylvain Cetre, Peter Wizinowich, Robert J. De Rosa, Garreth Ruane, Michael C. Liu, Carlos Alvarez, Christoph Baranec, Élodie Choquet, Mark Chun, Jacques-Robert Delorme, Gaspard Duchêne, Andrea Ghez, Olivier Guyon, Donald N. B. Hall, Rebecca Jensen-Clem, Nemanja Jovanovic, Scott Lilley, François Ménard, Tiffany Meshkat, Maxwell Millar-Blanchaer, Henry Ngo, Christophe Pinte, Sam Ragland, Ji Wang, Ed Wetherell, Jonathan P. Williams, Marie Ygouf, Ben Zuckerman

Comments: 21 pages, 5 figures, Accepted to AJ

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

We present $L$'-band imaging of the PDS 70 planetary system with Keck/NIRC2 using the new infrared pyramid wavefront sensor. We detected both PDS 70 b and c in our images, as well as the front rim of the circumstellar disk. After subtracting off a model of the disk, we measured the astrometry and photometry of both planets. Placing priors based on the dynamics of the system, we estimated PDS 70 b to have a semi-major axis of $20^{+3}_{-4}$~au and PDS 70 c to have a semi-major axis of $34^{+12}_{-6}$~au (95\% credible interval). We fit the spectral energy distribution (SED) of both planets. For PDS 70 b, we were able to place better constraints on the red half of its SED than previous studies and inferred the radius of the photosphere to be 2-3~$R_{Jup}$. The SED of PDS 70 c is less well constrained, with a range of total luminosities spanning an order of magnitude. With our inferred radii and luminosities, we used evolutionary models of accreting protoplanets to derive a mass of PDS 70 b between 2 and 4 $M_{\textrm{Jup}}$ and a mean mass accretion rate between $3 \times 10^{-7}$ and $8 \times 10^{-7}~M_{\textrm{Jup}}/\textrm{yr}$. For PDS 70 c, we computed a mass between 1 and 3 $M_{\textrm{Jup}}$ and mean mass accretion rate between $1 \times 10^{-7}$ and $5 \times~10^{-7} M_{\textrm{Jup}}/\textrm{yr}$. The mass accretion rates imply dust accretion timescales short enough to hide strong molecular absorption features in both planets' SEDs.

[24]  arXiv:2004.09606 [pdf, other]

Title: H$α$ Distances to the Leading Arm of the Magellanic Stream

Authors: Jacqueline Antwi-Danso, Kathleen A. Barger, L. Matthew Haffner

Comments: 13 pages, 5 figures, published in ApJ

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

The Leading Arm is a tidal feature that is in front of the Magellanic Clouds on their orbit through the Galaxy's halo. Many physical properties of the Leading Arm, such as its mass and size, are poorly constrained because it has few distance measurements. While H$\alpha$ measurements have been used to estimate the distances to halo clouds, many studies have been unsuccessful in detecting H$\alpha$ from the Leading Arm. In this study, we explore a group of H I clouds which lie $75^{\circ} - 90^{\circ}$ from the Magellanic Clouds. Through ultraviolet and 21-cm radio spectroscopy, this region, dubbed the Leading Arm Extension, was found to have chemical and kinematic similarities to the Leading Arm. Using the Wisconsin H$\alpha$ Mapper, we detect H$\alpha$ emission in four out of seven of our targets. Assuming that this region is predominantly photoionized, we use a radiation model that incorporates the contributions of the Galaxy, Magellanic Clouds, and the extragalactic background at $\rm z = 0$ to derive a heliocentric distance of $d_{\odot}\ge13.4~kpc$. We also use this model to rederive H$\alpha$ distances of $d_{\odot} \geq 5.0$ kpc and $d_{\odot} \geq 22.9~kpc$ to two clouds in the literature that might also be associated with the Leading Arm. Using these new measurements, and others in the literature, we provide a general trend of the variation of Leading Arm heliocentric distance as a function of Magellanic Stream longitude, and explore its implications for the origin and closest point of approach of the Leading Arm.

[25]  arXiv:2004.09609 [pdf, other]

Title: Solar slow magneto-acoustic-gravity waves: an erratum correction and a revisited scenario

Authors: E. Zurbriggen, M. V. Sieyra, A. Costa, A. Esquivel, G. Stenborg

Comments: 12 pages, 7 figures. MNRAS

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

Slow waves are commonly observed on the entire solar atmosphere. Assuming a thin flux tube approximation, the cut-off periods of slow-mode magneto-acoustic-gravity waves that travel from the photosphere to the corona were obtained in Costa et al. (2018). In that paper, however, a typo in the specific heat coefficient at constant pressure $c_{\mathrm{p}}$ value led to an inconsistency in the cut-off calculation, which is only significant at the transition region. Due to the abrupt temperature change in the region, a change of the mean atomic weight (by a factor of approximately two) also occurs, but is often overlooked in analytical models for simplicity purposes. In this paper, we revisit the calculation of the cut-off periods of magneto-acoustic-gravity waves in Costa et al. (2018) by considering an atmosphere in hydrostatic equilibrium with a temperature profile, with the inclusion of the variation of the mean atomic weight and the correction of the inconsistency aforementioned. In addition, we show that the cut-off periods obtained analytically are consistent with the corresponding periods measured in observations of a particular active region.

[26]  arXiv:2004.09636 [pdf, other]

Title: Searching for globular cluster chemical anomalies on the main sequence of a young massive cluster

Authors: I. Cabrera-Ziri, J. S. Speagle, E. Dalessandro, C. Usher, N. J. Bastian, M. Salaris, S. Martocchia, V. Kozhurina-Platais, F. Niederhofer, C. Lardo, S.S. Larsen, S. Saracino

Comments: 9 pages, 8 figures, accepted for publication in MNRAS

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

The spectroscopic and photometric signals of the star-to-star abundance variations found in globular clusters seem to be correlated with global parameters like the cluster's metallicity, mass and age. Understanding this behaviour could bring us closer to the origin of these intriguing abundance spreads. In this work we use deep HST photometry to look for evidence of abundance variations in the main sequence of a young massive cluster NGC 419 ($\sim10^5$ M$_{\odot}$, $\sim1.4$ Gyr). Unlike previous studies, here we focus on stars in the same mass range found in old globulars ($\sim0.75-1$ M$_{\odot}$), where light elements variations are detected. We find no evidence for N abundance variations among these stars in the $Un-B$ and $U-B$ CMD of NGC 419. This is at odds with the N-variations found in old globulars like 47 Tuc, NGC 6352 and NGC 6637 with similar metallicity to NGC 419. Although the signature of the abundance variations characteristic of old globulars appears to be significantly smaller or absent in this young cluster, we cannot conclude if this effect is mainly driven by its age or its mass.

[27]  arXiv:2004.09648 [pdf, other]

Title: Gemini Near-Infrared Field Spectrograph Observations of the Seyfert 2 Galaxy Mrk 3: Feeding and Feedback on Galactic and Nuclear Scales

Authors: C. L. Gnilka, D. M. Crenshaw, T. C. Fischer, M. Revalski, B. Meena, F. Martinez, G. E. Polack, C. Machuca, D. Dashtamirova, S. B. Kraemer, H. R. Schmitt, R. A. Riffel, T. Storchi-Bergmann

Comments: Accepted for Publication in ApJ on March 13, 2020. The paper has 30 pages and 17 figures

Journal-ref: The Astrophysical Journal, 893:80 (19pp), 2020 April 10

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

We explore the kinematics of the stars, ionized gas, and warm molecular gas in the Seyfert 2 galaxy Mrk~3 (UGC~3426) on nuclear and galactic scales with {\it Gemini} Near-Infrared Field Spectrograph (NIFS) observations, previous {\it Hubble Space Telescope} data, and new long-slit spectra from the {\it Apache Point Observatory} ({\it APO}) 3.5 m telescope. The {\it APO} spectra are consistent with our previous suggestion that a galactic-scale gas/dust disk at PA $=$ 129\arcdeg, offset from the major axis of the host S0 galaxy at PA $=$ 28\arcdeg, is responsible for the orientation of the extended narrow-line region (ENLR). The disk is fed by an H~I tidal stream from a gas-rich spiral galaxy (UGC~3422) $\sim$100 kpc to the NW of Mrk 3, and is ionized by the AGN to a distance of at least $\sim$20\arcsec\ ($\sim$5.4 kpc) from the central supermassive black hole (SMBH). The kinematics within at least 320 pc of the SMBH are dominated by outflows with radial (line of sight) velocities up to 1500 km s$^{-1}$ in the ionized gas and 500 km s$^{-1}$ in the warm molecular gas, consistent with in situ heating, ionization, and acceleration of ambient gas to produce the narrow-line region (NLR) outflows. There is a disk of ionized and warm molecular gas within $\sim$400 pc of the SMBH that has re-oriented close to the stellar major axis but is counter-rotating, consistent with claims of external fueling of AGN in S0 galaxies.

[28]  arXiv:2004.09658 [pdf, other]

Title: A new facility for airborne solar astronomy: NASA's WB-57 at the 2017 total solar eclipse

Authors: Amir Caspi, Daniel B. Seaton, Constantine C. C. Tsang, Craig E. DeForest, Paul Bryans, Edward E. DeLuca, Steven Tomczyk, Joan T. Burkepile, Thomas "Tony" Casey, John Collier, Donald "DD" Darrow, Dominic Del Rosso, Daniel D. Durda, Peter T. Gallagher, Leon Golub, Matthew Jacyna, David "DJ" Johnson, Philip G. Judge, Cary "Diddle" Klemm, Glenn T. Laurent, Johanna Lewis, Charles J. Mallini, Thomas "Duster" Parent, Timothy Propp, Andrew J. Steffl, Jeff Warner, Matthew J. West, John Wiseman, Mallory Yates, Andrei N. Zhukov, the NASA WB-57 2017 Eclipse Observing Team

Comments: 17 pages, 10 figures; accepted for publication by the Astrophysical Journal

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

NASA's WB-57 High Altitude Research Program provides a deployable, mobile, stratospheric platform for scientific research. Airborne platforms are of particular value for making coronal observations during total solar eclipses because of their ability both to follow the Moon's shadow and to get above most of the atmospheric airmass that can interfere with astronomical observations. We used the 2017 Aug 21 eclipse as a pathfinding mission for high-altitude airborne solar astronomy, using the existing high-speed visible-light and near-/mid-wave infrared imaging suite mounted in the WB-57 nose cone. In this paper, we describe the aircraft, the instrument, and the 2017 mission; operations and data acquisition; and preliminary analysis of data quality from the existing instrument suite. We describe benefits and technical limitations of this platform for solar and other astronomical observations. We present a preliminary analysis of the visible-light data quality and discuss the limiting factors that must be overcome with future instrumentation. We conclude with a discussion of lessons learned from this pathfinding mission and prospects for future research at upcoming eclipses, as well as an evaluation of the capabilities of the WB-57 platform for future solar astronomy and general astronomical observation.

[29]  arXiv:2004.09670 [pdf]

Title: A Hybrid method of accurate classification for Blazars Of Uncertain Type in Fermi LAT Catalogs

Authors: Yijun Xu, Weirong Huang, Hui Deng, Ying Mei, Feng Wang

Comments: 16 Pages, APJ

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

Significant progress in the classification of Fermi unassociated sources , has led to an increasing number of blazars are being found. The optical spectrum is effectively used to classify the blazars into two groups such as BL Lacs and flat spectrum radio quasars (FSRQs). However, the accurate classification of the blazars without optical spectrum information, i.e., blazars of uncertain type (BCUs), remains a significant challenge. In this paper, we present a principal component analysis (PCA) and machine learning hybrid blazars classification method. The method, based on the data from Fermi LAT 3FGL Catalog, first used the PCA to extract the primary features of the BCUs and then used a machine learning algorithm to further classify the BCUs. Experimental results indicate that the that the use of PCA algorithms significantly improved the classification. More importantly, comparison with the Fermi LAT 4FGL Catalog, which contains the spectral classification of those BCUs in the Fermi-LAT 3FGL Catalog, reveals that the proposed classification method in the study exhibits higher accuracy than currently established methods; specifically, 151 out of 171 BL Lacs and 19 out of 24 FSRQs are correctly classified.

[30]  arXiv:2004.09686 [pdf, other]

Title: Blazar -- IceCube neutrino association revisited

Authors: Jia-Wei Luo, Bing Zhang

Comments: 6 pages, 5 figures, to appear in PRD

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

The reported association of high-energy neutrino event IceCube-170922A and blazar TXS 0506+056 has sparkled discussion about blazars as sources of cosmic neutrinos. In this paper, we use publicly released IceCube data and blazar locations from Roma-BzCat to test spacial correlation between neutrino events and blazar locations. We also scrutinize the correlation between $\gamma$-ray flux and neutrino flux of blazars by applying a temporal filter onto the data based on Fermi monitored source list. We find no compelling evidence to prove blazars as the main source of cosmic neutrinos, as known before the detected IceCube-170922A / TXS 0506+056 association. While we do not rule out the association between IceCube-170922A and TXS 0506+056, the significance level we obtained is not high enough to claim a strong association. If such an association is real, a special physical condition is desired to allow a small fraction of blazars to become bright neutrino sources.

[31]  arXiv:2004.09698 [pdf, other]

Title: MOBSTER -- IV. Detection of a new magnetic B-type star from follow-up spectropolarimetric observations of photometrically selected candidates

Authors: A. David-Uraz, M. E. Shultz, V. Petit, D. M. Bowman, C. Erba, R. A. Fine, C. Neiner, H. Pablo, J. Sikora, A. ud-Doula, G. A. Wade

Comments: 9 pages, 6 figures, 2 tables, submitted to MNRAS

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

In this paper, we present results from the spectropolarimetric follow-up of photometrically selected candidate magnetic B stars from the MOBSTER project. Out of four observed targets, one (HD 38170) is found to host a detectable surface magnetic field, with a maximum longitudinal field measurement of 105$\pm$14 G. This star is chemically peculiar and classified as an $\alpha^2$ CVn variable. Its detection validates the use of TESS to perform a photometric selection of magnetic candidates. Furthermore, upper limits are derived for the remaining three stars, and we report the discovery of a previously unknown spectroscopic binary system, HD 25709. Finally, we use our non-detections as case studies to further inform the criteria to be used for the selection of a larger sample of stars to be followed up using high-resolution spectropolarimetry.

[32]  arXiv:2004.09700 [pdf, other]

Title: Inferring the population properties of binary black holes from unresolved gravitational waves

Authors: Rory Smith, Colm Talbot, Francisco Hernandez Vivanco, Eric Thrane

Comments: 10 pages, 7 figures,

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

The vast majority of compact binary mergers in the Universe produce gravitational waves that are too weak to yield unambiguous detections; they are unresolved. We present a method to infer the population properties of compact binaries -- such as their merger rates, mass spectrum, and spin distribution -- using both resolved and unresolved gravitational waves. By eliminating entirely the distinction between resolved and unresolved signals, we eliminate bias from selection effects. To demonstrate this method, we carry out a Monte Carlo study using an astrophysically motivated population of binary black holes. We show that some population properties of compact binaries are well constrained by unresolved signals after about one week of observation with Advanced LIGO at design sensitivity.

[33]  arXiv:2004.09716 [pdf, other]

Title: One star, two stars, or both? Investigating metallicity-dependant models for Gamma-Ray Burst progenitors with the IllustrisTNG simulation

Authors: Benjamin Metha, Michele Trenti

Comments: 13 pages, 7 figures, to be published in Monthly Notices of the Royal Astronomical Society

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

The rate of long-duration gamma ray bursts (GRBs) has been identified as a potential proxy for the star formation rate (SFR) across redshift, but the exact relationship depends on GRB progenitor models (single versus binary). The single-progenitor collapsar model accounts for the preference towards low-metallicity GRB progenitors, but is in apparent tension with some high-metallicity GRB host galaxy measurements. As a possible solution, we consider the scenario where high-metallicity GRB hosts harbour low metallicity regions in which GRB progenitors form. For this, we use the IllustrisTNG cosmological hydrodynamical simulation to investigate the internal metallicity distribution of GRB hosts, implementing in post-processing different GRB formation models. Predictions (GRB rate, host metallicities and stellar masses) are compared to the high-completeness GRB legacy surveys BAT6 and SHOALS and a sample of high-redshift GRB-DLA metallicities, allowing us to compute their relative likelihoods. When the internal metallicity distribution of galaxies is ignored, the best-fitting model requires a metallicity-independent channel, as previously proposed by Trenti, Perna & Jimenez. However, when the internal metallicity distribution is considered, a basic metallicity bias model with a cutoff at $Z_{max}=0.35Z_\odot$ is the best fitting one. Current data are insufficient to discriminate among more detailed metallicity bias models, such as weak metallicity dependence of massive binaries vs stronger metallicity bias of collapsars. An increased sample of objects, and direct measurements of host stellar masses at redshift $z>2$ would allow to further constrain the origin of long GRBs.

[34]  arXiv:2004.09771 [pdf, other]

Title: How magnetic activity alters what we learn from stellar spectra

Authors: Lorenzo Spina, Thomas Nordlander, Andrew R. Casey, Megan Bedell, Valentina D'Orazi, Jorge Meléndez, Amanda I. Karakas, Silvano Desidera, Martina Baratella, Jhon J. Yana Galarza, Giada Casali

Comments: Accepted for publication by ApJ. 19 pages, 6 figures, 6 tables

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

Magnetic fields and stellar spots can alter the equivalent widths of absorption lines in stellar spectra, varying during the activity cycle. This also influences the information that we derive through spectroscopic analysis. In this study we analyse high-resolution spectra of 211 Sun-like stars observed at different phases of their activity cycles, in order to investigate how stellar activity affects the spectroscopic determination of stellar parameters and chemical abundances. We observe that equivalent widths of lines can increase as a function of the activity index log R$^\prime_{\rm HK}$ during the stellar cycle, which also produces an artificial growth of the stellar microturbulence and a decrease in effective temperature and metallicity. This effect is visible for stars with activity indexes log R$^\prime_{\rm HK}$$\geq$$-$5.0 (i.e., younger than 4-5 Gyr) and it is more significant at higher activity levels. These results have fundamental implications on several topics in astrophysics that are discussed in the paper, including stellar nucleosynthesis, chemical tagging, the study of Galactic chemical evolution, chemically anomalous stars, the structure of the Milky Way disk, stellar formation rates, photoevaporation of circumstellar disks, and planet hunting.

[35]  arXiv:2004.09772 [pdf, other]

Title: Electron-positron pair plasma in TXS 0506+056 and the "neutrino flare" in 2014 - 2015

Authors: Nissim Fraija, Edilberto Aguilar-Ruiz, Antonio Galván-Gámez

Comments: 12 pages, 4 figures

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

The detection of a long flaring activity from blazar TXS 0506+056 in temporal and spatial coincidence with the energetic neutrino IceCube-170922A provided evidence about the photo-hadronic interactions in this source. However, analysis of the archival neutrino and multi-wavelength data from the direction of this blazar between September 2014 and March 2015 revealed a "neutrino flare" without observing quasi-simultaneous activity in the gamma-ray bands, posing challenges to established models. Electron-positron ($e^\pm$) pairs generated from the accretion disks have been amply proposed as a mechanism of bulk acceleration of sub-relativistic and relativistic jets. These pairs annihilate inside the source producing a line around the electron mass which is expected to be blueshifted in the observed frame (on Earth) and redshifted in the frame of the dissipation region of the jet. The redshifted photons in the dissipation region interact with accelerated protons, producing high-energy neutrinos that contribute significantly to the diffuse neutrino flux in the $\sim$ 10 - 20 TeV energy range in connection with gamma-rays from photo-pion process which can be detected by future MeV orbiting satellites. Based on this phenomenological model we can explain the "neutrino flare" reported in 2014 - 1015.

[36]  arXiv:2004.09785 [pdf, other]

Title: Long-term Evolution of the Solar Corona Using PROBA2 Data

Authors: Marilena Mierla, Jan Janssens, Elke D'Huys, Laurence Wauters, Matthew J. West, Daniel B. Seaton, David Berghmans, Elena Podladchikova

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

We use The Sun Watcher with Active Pixel System detector and Image Processing (SWAP) imager onboard the Project for Onboard Autonomy 2 (PROBA2) mission to study the evolution of large-scale EUV structures in the solar corona observed throughout Solar Cycle 24 (from 2010 to 2019). We discuss the evolution of the on-disk coronal features and at different heights above the solar surface based on EUV intensity changes. We also look at the evolution of the corona in equatorial and polar regions and compare them at different phases of the solar cycle, as well as with sunspot number evolution and with the PROBA2/Lyman-Alpha Radiometer (LYRA) signal. The main results are as follows: The three time series (SWAP on-disk average brightness, sunspot number and LYRA irradiance) are very well correlated, with correlation coefficients around 0.9. The average rotation rate of bright features at latitudes of +15, 0, and -15 degrees was around 15 degree/day throughout the period studied. A secondary peak in EUV averaged intensity at the Poles was observed on the descending phase of SC24. These peaks (at North and South poles respectively) seem to be associated with the start of the development of the (polar) coronal holes. Large-scale off-limb structures were visible from around March 2010 to around March 2016, meaning that they were absent at the minimum phase of solar activity. A fan at the North pole persisted for more than 11 Carrington rotations (February 2014 to March 2015), and it could be seen up to altitudes of 1.6 Rs.

[37]  arXiv:2004.09818 [pdf, other]

Title: The assembly history of the nearest S0 galaxy NGC 3115 from its kinematics out to six half-light radii

Authors: Arianna Dolfi, Duncan A. Forbes, Warrick J. Couch, Anna Ferre-Mateu, Sabine Bellstedt, Kenji Bekki, Jonathan Diaz, Aaron J. Romanowsky, Jean P. Brodie

Comments: 23 pages, 14 figures, accepted for publication by MNRAS

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

Using new and archival data, we study the kinematic properties of the nearest field S0 galaxy, NGC 3115, out to $\sim6.5$ half-light radii ($R_\mathrm{e}$) from its stars (integrated starlight), globular clusters (GCs) and planetary nebulae (PNe). We find evidence of three kinematic regions with an inner transition at $\sim0.2\ R_\mathrm{e}$ from a dispersion-dominated bulge ($V_\mathrm{rot}/\sigma <1$) to a fast-rotating disk ($V_\mathrm{rot}/\sigma >1$), and then an additional transition from the disk to a slowly rotating spheroid at $\sim2-2.5\, R_\mathrm{e}$, as traced by the red GCs and PNe (and possibly by the blue GCs beyond $\sim5\, R_\mathrm{e}$). From comparison with simulations, we propose an assembly history in which the original progenitor spiral galaxy undergoes a gas-rich minor merger that results in the embedded kinematically cold disk that we see today in NGC 3115. At a later stage, dwarf galaxies, in mini mergers (mass-ratio $<$ 1:10), were accreted building-up the outer slowly rotating spheroid, with the central disk kinematics largely unaltered. Additionally, we report new spectroscopic observations of a sample of ultra-compact dwarfs (UCDs) around NGC 3115 with the Keck/KCWI instrument. We find that five UCDs are inconsistent with the general rotation field of the GCs, suggesting an \textit{ex-situ} origin for these objects, i.e. perhaps the remnants of tidally stripped dwarfs. A further seven UCDs follow the GC rotation pattern, suggesting an \textit{in-situ} origin and, possibly a GC-like nature.

[38]  arXiv:2004.09830 [pdf, other]

Title: The spectral impact of magnetic activity on disk-integrated HARPS-N solar observations: exploring new activity indicators

Authors: A. P. G. Thompson, C. A. Watson, R. D. Haywood, J. C. Costes, E. de Mooij, A. Collier Cameron, X. Dumusque, D. F. Phillips, S. H. Saar, A. Mortier, T. W. Milbourne, S. Aigrain, H. M. Cegla, D. Charbonneau, R. Cosentino, A. Ghedina, D. W. Latham, M. López-Morales, G. Micela, E. Molinari, E. Poretti, A. Sozzetti, S. Thompson, R. Walsworth

Comments: 13 pages, 10 figures, accepted for publication in the Monthly Notices of the Royal Astronomical Society

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

Stellar activity is the major roadblock on the path to finding true Earth-analogue planets with the Doppler technique. Thus, identifying new indicators that better trace magnetic activity (i.e. faculae and spots) is crucial to aid in disentangling these signals from that of a planet's Doppler wobble. In this work, we investigate activity related features as seen in disk-integrated spectra from the HARPS-N solar telescope. We divide high-activity spectral echelle orders by low-activity master templates (as defined using both log R'HK and images from the Solar Dynamics Observatory, SDO), creating "relative spectra". With resolved images of the surface of the Sun (via SDO), the faculae and spot filling factors can be calculated, giving a measure of activity independent of, and in addition to, log R'HK. We find pseudo-emission (and pseudo-absorption) features in the relative spectra that are similar to those reported in our previous work on alpha Cen B. In alpha Cen B, the features are shown to correlate better to changes in faculae filling factor than spot filling factor. In this work we more confidently identify changes in faculae coverage of the visible hemisphere of the Sun as the source of features produced in the relative spectra. Finally, we produce trailed spectra to observe the RV component of the features, which show that the features move in a redward direction as one would expect when tracking active regions rotating on the surface of a star.

[39]  arXiv:2004.09840 [pdf, other]

Title: Laboratory disruption of scaled astrophysical outflows by a misaligned magnetic field

Authors: G. Revet, B. Khiar, E. Filippov, C. Argiroffi, J. Béard, R. Bonito, M. Cerchez, S. N. Chen, T. Gangolf, D. P. Higginson, A. Mignone, B. Olmi, M. Ouillé, S. N. Ryazantsev, I. Yu. Skobelev, M. I. Safronova, M. Starodubtsev, T. Vinci, O. Willi, S. Pikuz, S. Orlando, A. Ciardi, J. Fuchs

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

The shaping of astrophysical outflows into bright, dense and collimated jets due to magnetic pressure is here investigated using laboratory experiments. We notably look at the impact on jet collimation of a misalignment between the outflow, as it stems from the source, and the magnetic field. For small misalignments, a magnetic nozzle forms and redirects the outflow in a collimated jet. For growing misalignments, this nozzle becomes increasingly asymmetric, disrupting jet formation. Our results thus suggest outflow/magnetic field misalignment to be a plausible key process regulating jet collimation in a variety of objects. Furthermore, they provide a possible interpretation for the observed structuring of astrophysical jets. Jet modulation could be interpreted as the signature of changes over time in the outflow/ambient field angle, and the change in the direction of the jet could be the signature of changes in the direction of the ambient field.

[40]  arXiv:2004.09841 [pdf, other]

Title: White Paper: ARIANNA-200 high energy neutrino telescope

Authors: A. Anker, P. Baldi, S. W. Barwick, D. Bergman, H. Bernhoff, D. Z. Besson, N. Bingefors, O. Botner, P. Chen, Y. Chen, D. García-Fernández, G. Gaswint, C. Glaser, A. Hallgren, J. C. Hanson, J. J. Huang, S. R. Klein, S. A. Kleinfelder, C.-Y. Kuo, R. Lahmann, U. Latif, T. Liu, Y. Lyu, S. McAleer, J. Nam, A. Novikov, A. Nelles, M. P. Paul, C. Persichilli, I. Plaisier, J. Y. Shiao, J. Tatar, A. van Vliet, S.-H. Wang, Y.-H. Wang, C. Welling

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

The proposed ARIANNA-200 neutrino detector, located at sea-level on the Ross Ice Shelf, Antarctica, consists of 200 autonomous and independent detector stations separated by 1 kilometer in a uniform triangular mesh, and serves as a pathfinder mission for the future IceCube-Gen2 project. The primary science mission of ARIANNA-200 is to search for sources of neutrinos with energies greater than 10^17 eV, complementing the reach of IceCube. An ARIANNA observation of a neutrino source would provide strong insight into the enigmatic sources of cosmic rays. ARIANNA observes the radio emission from high energy neutrino interactions in the Antarctic ice. Among radio based concepts under current investigation, ARIANNA-200 would uniquely survey the vast majority of the southern sky at any instant in time, and an important region of the northern sky, by virtue of its location on the surface of the Ross Ice Shelf in Antarctica. The broad sky coverage is specific to the Moore's Bay site, and makes ARIANNA-200 ideally suited to contribute to the multi-messenger thrust by the US National Science Foundation, Windows on the Universe - Multi-Messenger Astrophysics, providing capabilities to observe explosive sources from unknown directions. The ARIANNA architecture is designed to measure the angular direction to within 3 degrees for every neutrino candidate, which too plays an important role in the pursuit of multi-messenger observations of astrophysical sources.

[41]  arXiv:2004.09871 [pdf, ps, other]

Title: Dimension dependence of numerical simulations on gravitational waves from protoneutron stars

Authors: Hajime Sotani, Tomoya Takiwaki

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

We examine the eigenfrequencies of gravitational waves from the protoneutron stars (PNSs) provided via the core-collapse supernovae, focusing on how the frequencies depend on the dimension of numerical simulations especially for the early phase after core bounce. As expected, we find that the time evolution of gravitational wave frequencies depends strongly on the dimension of numerical simulation as well as the equation of state for high density matter. Even so, we find that the fundamental frequency as a function of PNS average density and the ratio of the specific eigenfrequencies to the fundamental frequency as a function of PNS properties are independent of the dimension of the numerical simulations, where the dependence of the equation of state is also very weak in this early postbounce phase. Thus, one can safely discuss the gravitational wave frequencies of the PNSs as a function of the PNS average density or compactness even with the frequencies obtained from the one dimensional simulations. We also provide phenomenological relation between the compactness and average density as well as the relation among the $f$-, $p$-, and $g$- mode frequencies.

[42]  arXiv:2004.09872 [pdf]

Title: Style and intensity of hydration among C-complex asteroids: a comparison to dessicated carbonaceous chondrites

Authors: S. Potin, P. Beck, F. Usui, L. Bonal, P. Vernazza, B. Schmitt

Comments: Accepted for publication in Icarus

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

Here we report a comparison between reflectance spectroscopy of meteorites under asteroidal environment (high vacuum and temperature) and Main Belt and Near Earth Asteroids spectra. Focusing on the OH absorption feature around 3{\mu}m, we show that the asteroidal environment induces a reduction of depth and width of the band, as well as a shift of the reflectance minimum. We then decompose the OH feature into several components with a new model using Exponentially Modified Gaussians. Unlike previous studies, we confirme the link between these components, the aqueous alteration history and the amount of water molecules inside of the sample, using the shape of this spectral feature only. We then apply this deconvolution model to asteroids spectra which were obtained with a space-borne telescope and two space probes, and find a strong similarity with the components detected on meteorites, and among asteroids from a same type. Based on the conclusions drawn from our meteorites experiment, we suggest to use the 3-{\mu}m band as a tracer of the alteration history of the small bodies. Using the 3-{\mu}m band only, we show that Ryugu has been heavily altered by water, which is consistent with its parent body being covered with water ice, then went through a high temperature sequence, over 400{\deg}C. We also point out that the 3-{\mu}m band of Bennu shows signs of its newly discovered surface activity.

[43]  arXiv:2004.09873 [pdf, other]

Title: Sub-galactic scaling relations between X-ray luminosity, star-formation rate, and stellar mass

Authors: Konstantinos Kouroumpatzakis, Andreas Zezas, Paul Sell, Konstantinos Kovlakas, Paolo Bonfini, Steven Willner, Matthew Ashby, Alexandros Maragkoudakis, Thomas Jarrett

Comments: 19 pages, 13 figures, accepted for publication in MNRAS (2020-04-19)

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

X-ray luminosity ($L_X$) originating from high-mass X-ray binaries (HMXBs) is tightly correlated with the host galaxy's star-formation rate (SFR). We explore this connection at sub-galactic scales spanning ${\sim}$7 dex in SFR and ${\sim}$8 dex in specific SFR (sSFR). There is good agreement with established relations down to ${\rm SFR {\simeq} 10^{-3}\,M_\odot \, yr^{-1}}$, below which an excess of X-ray luminosity emerges. This excess likely arises from low mass X-ray binaries. The intrinsic scatter of the $L_X$-SFR relation is constant, not correlated with SFR. Different star formation indicators scale with $L_X$ in different ways, and we attribute the differences to the effect of star formation history. The SFR derived from H$\alpha$ shows the tightest correlation with X-ray luminosity because H$\alpha$ emission probes stellar populations with ages similar to HMXB formation timescales, but the H$\alpha$-based SFR is reliable only for $\rm sSFR{>}10^{-12}\,M_\odot \, yr^{-1}/M_\odot$.

[44]  arXiv:2004.09916 [pdf, ps, other]

Title: KIC 10736223: An Algol-type eclipsing binary just undergone the rapid mass-transfer stage

Authors: Xinghao Chen, Xiaobin Zhang, Yan Li, Hailiang Chen, Changqing Luo, Jie Su, Xuefei Chen, Zhanwen Han

Comments: 19 pages, 7 figures, and 8 tables. Accepted by ApJ

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

This paper reports the discovery of an Algol system KIC 10736223 that just past the rapid mass transfer stage. From the light curve and radial-velocity modelling we find KIC 10736223 to be a detached Algol system with the less-massive secondary nearly filling its Roche lobe. Based on the short-cadence Kepler data, we analyzed intrinsic oscillations of the pulsator and identified six secured independent $\delta$ Scuti-type pulsation modes ($f_{1}$, $f_3$, $f_{9}$, $f_{19}$, $f_{42}$, and $f_{48}$). We compute two grids of theoretical models to reproduce the $\delta$ Scuti freqiencies, and find fitting results of mass-accreting models meet well with those of single-star evolutionary models. The fundamental parameters of the primary star yielded with asteroseismology are $M$ = $1.57^{+0.05}_{-0.09}$ $M_{\odot}$, $Z$ = 0.009 $\pm$ 0.001, $R$ = $1.484^{+0.016}_{-0.028}$ $R_{\odot}$, $\log g$ = $4.291^{+0.004}_{-0.009}$, $T_{\rm eff}$ = $7748^{+230}_{-378}$ K, $L$ = $7.136^{+1.014}_{-1.519}$ $L_{\odot}$. The asteroseismic parameters match well with the dynamical parameters derived from the binary model. Moreover, our asteroseismic results show that the pulsator is an almost unevolved star with an age between 9.46-11.65 Myr for single-star evolutionary models and 2.67-3.14 Myr for mass-accreting models. Thereofore, KIC 10736223 may be an Algol system that has just undergone the rapid mass-transfer process.

[45]  arXiv:2004.09956 [pdf, other]

Title: Characterization of the umbra-penumbra boundary by the vertical component of the magnetic field -- Analysis of ground-based data from the GREGOR Infrared Spectrograph

Authors: P. Lindner, R. Schlichenmaier, N. Bello González

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

The vertical component of the magnetic field ($B_\perp$) was found to reach a constant value at the umbra-penumbra boundary of stable sunspots in a recent statistical study of Hinode/SP data. The objective of this work is to verify the existence of a constant value for $B_\perp$ at the umbra-penumbra boundary from ground-based data in the near-infrared wavelengths and to determine its value for GREGOR Infrared Spectrograph (GRIS) data. This is the first statistical study on the Jurcak criterion with ground-based data, and we compare it with the results from Hinode and HMI data. Eleven spectropolarimetric data sets from the GRIS slit-spectograph containing stable sunspots were selected from the GRIS archive (sdc.leibniz-kis.de). SIR inversions including a polarimetric straylight correction are used to produce maps of the magnetic field vector using the Fe 1564.8 and 1566.2 nm lines. Averages of $B_\perp$ along umbra-penumbra boundaries are analyzed for the 11 data sets. Geometric differences between contours at the resulting $B_\perp^{\rm const}$ value and contours in intensity, $\Delta P$, are calculated. Averaged over the 11 sunspots, we find a value of $B_\perp=1787\pm100$ gauss. Contours at $B_\perp=B_\perp^{\rm const}$ and contours calculated in intensity maps match from a visual inspection and the geometric distance $\Delta P$ was found to be on the order of 2 pixels. Furthermore, the standard deviation between different data sets of averages along umbra--penumbra contours is smaller for $B_\perp$ than for $B_\parallel$ by a factor of 2.4. Our results provide further support to the Jurcak criterion with the existence of an invariable value $B_\perp^{\rm const}$ at the umbra--penumbra boundary. We also found that the geometric difference, $\Delta P$, between intensity contours and contours at $B_\perp=B_\perp^{\rm const}$ acts as an index of stability for sunspots.

[46]  arXiv:2004.09961 [pdf, other]

Title: The GBOT Asteroid Survey (First years: Jan. 2015 - May 2018)

Authors: S. Bouquillon, D. Souami

Comments: 4 pages, 4 figures, proceeding of the 8th ADeLA meeting, 2018, Tarija, Bolivia

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

The GBOT group is in charge of the Ground Based Optical Tracking of the Gaia satellite. In concrete terms, since the launch of Gaia, our task is to take every night, using ground based medium-class telescopes, short sequences of $10$ or $20$ images of the Gaia satellite close to its meridian transit. For this purpose, we mainly use the VLT Survey Telescope and the Liverpool Telescope. In these images, taken close to the Sun's opposition - since Gaia is in L$_2$ - we observe many asteroids: between $30$ and $100$ asteroids every night, up to magnitude $22$. In order to extract the astrometric positions as well as the magnitudes of these asteroids, we have developed semi-automatic methods, strategies and tools tailored explicitly for this daily task. In only three and a half years of operation, this system has allowed us to send to the Minor Planet Center the position and the photometry for about $20,000$ asteroids, amongst which $9,000$ new objects. Here we describe all the aspects of the GBOT asteroid survey.

[47]  arXiv:2004.09979 [pdf, other]

Title: Using quasar X-ray and UV flux measurements to constrain cosmological model parameter

Authors: Narayan Khadka, Bharat Ratra

Comments: 16 pages, 14 figures. arXiv admin note: text overlap with arXiv:1909.01400

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)

Risaliti and Lusso have compiled X-ray and UV flux measurements of 1598 quasars (QSOs) in the redshift range $0.036 \leq z \leq 5.1003$, part of which, $z \sim 2.4 - 5.1$, is largely cosmologically unprobed. In this paper we use these QSO measurements, alone and in conjunction with baryon acoustic oscillation (BAO) and Hubble parameter [$H(z)$] measurements, to constrain cosmological parameters in six different cosmological models, each with two different Hubble constant priors. In most of these models, given the larger uncertainties, the QSO cosmological parameter constraints are mostly consistent with those from the $H(z)$ + BAO data. A somewhat significant exception is the non-relativistic matter density parameter $\Omega_{m0}$ where the QSO data favors $\Omega_{m0} \sim 0.5 - 0.6$ in most models. Consequently in joint analyses of QSO data with $H(z)$ + BAO data the one-dimensional $\Omega_{m0}$ distributions shift slightly toward larger values. A joint analysis of the QSO + $H(z)$ + BAO data is consistent with the current standard model, spatially-flat $\Lambda$CDM, but mildly favors closed spatial hypersurfaces and dynamical dark energy. Since the higher $\Omega_{m0}$ values favored by the QSO data appear to be associated with the $z \sim 2 - 5$ part of these data, and conflict somewhat with strong indications for $\Omega_{m0} \sim 0.3$ from most $z < 2.5$ data as well as from the cosmic microwave background anisotropy data at $z \sim 1100$, in most models, the larger QSO data $\Omega_{m0}$ is possibly more indicative of an issue with the $z \sim 2 - 5$ QSO data than of an inadequacy of the standard flat $\Lambda$CDM model.

[48]  arXiv:2004.09991 [pdf, other]

Title: A Gaia early DR3 mock stellar catalog: Galactic prior and selection function

Authors: Jan Rybizki, Markus Demleitner, Coryn Bailer-Jones, Piero Dal Tio, Tristan Cantat-Gaudin, Morgan Fouesneau, Yang Chen, Rene Andrae, Leo Girardi, Sanjib Sharma

Comments: 22 pages, 20 figures, accepted by PASP, catalog info and download and ADQL interface: this http URL ; relevant github repositories: this https URL ; this https URL

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

We present a mock stellar catalog, matching in volume, depth and data model the content of the planned Gaia early data release 3 (Gaia EDR3). We have generated our catalog (GeDR3mock) using galaxia, a tool to sample stars from an underlying Milky Way (MW) model or from N-body data. We used an updated Besan\c{c}on Galactic model together with the latest PARSEC stellar evolutionary tracks, now also including white dwarfs. We added the Magellanic clouds and realistic open clusters with internal rotation. We empirically modelled uncertainties based on Gaia DR2 (GDR2) and scaled them according to the longer baseline in Gaia EDR3. The apparent magnitudes were reddened according to a new selection of 3D extinction maps.
To help with the Gaia selection function we provide all-sky magnitude limit maps in G and BP for a few relevant GDR2 subsets together with the routines to produce these maps for user-defined subsets. We supplement the catalog with photometry and extinctions in non-Gaia bands. The catalog is available in the Virtual Observatory and can be queried just like the actual Gaia EDR3 will be. We highlight a few capabilities of the Astronomy Data Query Language (ADQL) with educative catalog queries. We use the data extracted from those queries to compare GeDR3mock to GDR2, which emphasises the importance of adding observational noise to the mock data. Since the underlying truth, e.g. stellar parameters, is know in GeDR3mock, it can be used to construct priors as well as mock data tests for parameter estimation.
All code, models and data used to produce GeDR3mock are linked and contained in galaxia_wrap, a python package, representing a fast galactic forward model, able to project MW models and N-body data into realistic Gaia observables.

[49]  arXiv:2004.10015 [pdf, other]

Title: A Search for Gravitational Waves from Binary Mergers with a Single Observatory

Authors: Alexander H. Nitz, Thomas Dent, Gareth S. Davies, Ian Harry

Comments: 11 pages, 5 figures, 2 tables. Supplementary materials at this https URL

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

We present a search for merging compact binary gravitational-wave sources that produce a signal appearing solely or primarily in a single detector. Past analyses have heavily relied on coincidence between multiple detectors to reduce non-astrophysical background. However, for $\sim40\%$ of the total time of the 2015-2017 LIGO-Virgo observing runs only a single detector was operating. We discuss the difficulties in assigning significance and calculating the probability of astrophysical origin for candidates observed primarily by a single detector, and suggest a straightforward resolution using a noise model designed to provide a conservative assessment given the observed data. We also describe a procedure to assess candidates observed in a single detector when multiple detectors are observing. We apply these methods to search for binary black hole (BBH) and binary neutron star (BNS) mergers in the open LIGO data spanning 2015-2017. The most promising candidate from our search is 170817+03:02:46UTC (probability of astrophysical origin $p_{\rm astro} \sim 0.4$): if astrophysical, this is consistent with a BBH merger with primary mass $67_{-15}^{+21}\,M_{\odot}$, suggestive of a hierarchical merger origin. We also apply our method to the analysis of GW190425 and find $p_{\rm astro} \sim 0.5$, though this value is highly dependent on assumptions about the noise and signal models.

[50]  arXiv:2004.10028 [pdf, other]

Title: Phase coherence and phase jumps in the Schwabe cycle

Authors: F. Stefani, J. Beer, A. Giesecke, T. Gloaguen, M. Seilmayer, R. Stepanov, T. Weier

Comments: 14 pages, 16 figures

Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Geophysics (physics.geo-ph)

Guided by the working hypothesis that the Schwabe cycle of solar activity is synchronized by the 11.07 years alignment cycle of the tidally dominant planets Venus, Earth and Jupiter, we reconsider the phase diagrams of sediment accumulation data in lake Holzmaar, and of methanesulfonate (MSA) data in the Greenland ice core GISP2, which are available for the period 10000-9000 cal. BP. Since the half-cycle phase jumps appearing in the output signals are, very likely, artifacts of applying a biologically substantiated transfer function, the underlying solar input signal with a dominant 11.04 years periodicity can well be considered as mainly phase-coherent over the 1000 years period in the early Holocene. For more recent times, we show that the re-introduction of a hypothesized "lost cycle" at the beginning of the Dalton minimum would lead to a real phase jump. Similarly, by analyzing various series of $^{14}$C and $^{10}$Be data and comparing them with Schove's historical cycle maxima, we support the existence of another "lost cycle" around 1565, also connected with a phase jump. Viewed synoptically, our results lend greater plausibility to the starting hypothesis of a tidally synchronized solar cycle, which at times can undergo phase jumps, although the competing explanation in terms of a self-synchronizing solar dynamo cannot be completely ruled out.

[51]  arXiv:2004.10032 [pdf, other]

Title: The high-energy emission from HD~93129A near periastron

Authors: S. del Palacio, F. García, D. Altamirano, R. H. Barbá, V. Bosch-Ramon, M. Corcoran, M. De Becker, K. Hamaguchi, J. Maíz Apellániz, P. Munar Adrover, J. M. Paredes, G. E. Romero, H. Sana, M. Tavani, A. ud-Doula

Comments: 11 pages, 10 figures, accepted for publication in MNRAS

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

We conducted an observational campaign towards one of the most massive and luminous colliding wind binaries in the Galaxy, HD~93129A, close to its periastron passage in 2018. During this time the source was predicted to be in its maximum of high-energy emission. Here we present our data analysis from the X-ray satellites \textit{Chandra} and \textit{NuSTAR} and the $\gamma$-ray satellite \textit{AGILE}. High-energy emission coincident with HD~93129A was detected in the X-ray band up to $\sim$18~keV, whereas in the $\gamma$-ray band only upper limits were obtained. We interpret the derived fluxes using a non-thermal radiative model for the wind-collision region. We establish a conservative upper limit for the fraction of the wind kinetic power that is converted into relativistic electron acceleration, $f_\mathrm{NT,e} < 0.02$. In addition, we set a lower limit for the magnetic field in the wind-collision region as $B_\mathrm{WCR} > 0.3$~G. We also argue a putative interpretation of the emission from which we estimate $f_\mathrm{NT,e} \approx 0.006$ and $B_\mathrm{WCR} \approx 0.5$~G. We conclude that multi-wavelength, dedicated observing campaigns during carefully selected epochs are a powerful tool for characterising the relativistic particle content and magnetic field intensity in colliding wind binaries.

[52]  arXiv:2004.10056 [pdf, ps, other]

Title: Solar neutrinos as indicators of the Sun's activity

Authors: O.M.Boyarkin, I.O.Boyarkina

Comments: 19 page

Journal-ref: International Journal of Modern Physics A, Vol. 35 (2019) 1950448

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

Opportunity of the solar flares (SF's) prediction observing the solar neutrino fluxes is investigated. In three neutrino generations the evolution of the neutrino flux traveling the coupled sunspots (CS's) which are the SF source is considered. It is assumed that the neutrinos possess both the dipole magnetic moment and the anapole moment while the magnetic field above the CS's may reach the values $10^5-10^6$ Gs, displays the twisting nature and has the nonpotential character. The possible resonance conversions of the solar neutrino flux are examined. Since the $\nu_{eL}\to \nu_{\mu L}$ resonance takes place before the convective zone, its existence can in no way be connected with the SF. However, when the solar neutrino flux moves through the CS's in the preflare period, then it may undergo the additional resonance conversions and, as a result, depleting the electron neutrinos flux may be observed.

[53]  arXiv:2004.10094 [pdf, other]

Title: TW Hya: an old protoplanetary disc revived by its planet

Authors: Sergei Nayakshin, Takashi Tsukagoshi, Cassandra Hall, Allona Vazan, Ravit Helled, Jack Humphries, Farzana Meru, Patrick Neunteufel, Olja Panic, Daniel Price

Comments: Accepted to MNRAS, 22 pages

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

Dark rings with bright rims are the indirect signposts of planets embedded in protoplanetary discs. In a recent first, an azimuthally elongated AU-scale blob, possibly a planet, was resolved with ALMA in TW Hya. The blob is at the edge of a cliff-like rollover in the dust disc rather than inside a dark ring. Here we build time-dependent models of TW Hya disc. We find that the classical paradigm cannot account for the morphology of the disc and the blob. We propose that ALMA-discovered blob hides a Neptune mass planet losing gas and dust. We show that radial drift of mm-sized dust particles naturally explains why the blob is located on the edge of the dust disc. Dust particles leaving the planet perform a characteristic U-turn relative to it, producing an azimuthally elongated blob-like emission feature. This scenario also explains why a 10 Myr old disc is so bright in dust continuum. Two scenarios for the dust-losing planet are presented. In the first, a dusty pre-runaway gas envelope of about 40 Earth mass Core Accretion planet is disrupted, e.g., as a result of a catastrophic encounter. In the second, a massive dusty pre-collapse gas giant planet formed by Gravitational Instability is disrupted by the energy released in its massive core. Future modelling may discriminate between these scenarios and allow us to study planet formation in an entirely new way -- by analysing the flows of dust and gas recently belonging to planets, informing us about the structure of pre-disruption planetary envelopes.

[54]  arXiv:2004.10095 [pdf, other]

Title: The multi-planet system TOI-421 -- A warm Neptune and a super puffy mini-Neptune transiting a G9 V star in a visual binary

Authors: Ilaria Carleo, Davide Gandolfi, Oscar Barragán, John H. Livingston, Carina M. Persson, Kristine W. F. Lam, Aline Vidotto, Michael B. Lund, Carolina Villarreal D'Angelo, Karen A. Collins, LucaFossati, Andrew W. Howard, Daria Kubyshkina, Rafael Brahm, Antonija Oklopčić, Paul Mollière, Seth Redfield, Luisa Maria Serrano, Fei Dai, Malcolm Fridlund, Francesco Borsa, Judith Korth, Massimiliano Esposito, Matías R. Díaz, Louise Dyregaard Nielsen, Coel Hellier, Savita Mathur, Hans J. Deeg, Artie P. Hatzes, Serena Benatti, Florian Rodler, Javier Alarcon, Lorenzo Spina, Ângela R. G. Santos, Iskra Georgieva, Rafael A. García, Lucía González-Cuesta, George R. Ricker, Roland Vanderspek, David W. Latham, Sara Seager, Joshua N. Winn, Jon M. Jenkins, et al. (70 additional authors not shown)

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

We report the discovery of a warm Neptune and a hot sub-Neptune transiting TOI-421 (BD-14 1137, TIC 94986319), a bright (V=9.9) G9 dwarf star in a visual binary system observed by the TESS space mission in Sectors 5 and 6. We performed ground-based follow-up observations -- comprised of LCOGT transit photometry, NIRC2 adaptive optics imaging, and FIES, CORALIE, HARPS, HIRES, and PFS high-precision Doppler measurements -- and confirmed the planetary nature of the 16-day transiting candidate announced by the TESS team. We discovered an additional radial velocity signal with a period of 5 days induced by the presence of a second planet in the system, which we also found to transit its host star. We found that the outer warm Neptune, TOI-421 b, has an orbital period of Pb=16.06815+0.00034-0.00035 days, a mass of Mb=16.23+1.14-1.08 MEarth, a radius of Rb=5.17+-0.13 REarth and a density of rho_b=0.645+0.069-0.062 g/cm3, whereas the inner mini-Neptune, TOI-421 c, has a period of Pc=5.19676+0.00049-0.00048 days, a mass of Mc=7.05+0.71-0.70 MEarth and a radius of Rc=2.72+0.19-0.18 REarth. With its characteristics the latter planet (rho_c=1.93+0.49-0.39 g/cm3) is placed in the intriguing class of the super-puffy mini-Neptunes. TOI-421 b and c are found to be well suitable for atmospheric characterization. Our atmospheric simulations predict significant Ly-alpha transit absorption, due to strong hydrogen escape in both planets, and the presence of detectable CH4 in the atmosphere of TOI-421 b if equilibrium chemistry is assumed.

[55]  arXiv:2004.10097 [pdf, other]

Title: The spin-temperature dependence of the 21cm -- LAE cross-correlation

Authors: Caroline Heneka, Andrei Mesinger

Comments: 9 pages, 3 figures

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

Cross-correlating 21cm with known cosmic signals will be invaluable proof of the cosmic origin of the first 21cm detections. As some of the widest fields available, comprising thousands of sources with reasonably known redshifts, narrow-band Lyman alpha emitter (LAE) surveys are an obvious choice for such cross-correlation. Here we revisit the 21cm -- LAE cross-correlation, relaxing the common assumption of reionization occurring in a pre-heated intergalactic medium (IGM). Using specifications from the Square Kilometre Array and the Subary Hyper Supreme-Cam, we present new forecasts of the 21cm -- LAE cross-correlation function at $z\sim7$. We sample a broad parameter space of the mean IGM neutral fraction and spin temperature, ($\bar{x}_{\rm{HI}}$, $\bar{T}_{\rm S}$). The sign of the cross-correlation roughly follows the sign of the 21cm signal: ionized regions which surround LAEs correspond to relative hot spots in the 21cm signal when the neutral IGM is colder than the CMB, and relative cold spots when the neutral IGM is hotter than the CMB. The amplitude of the cross-correlation function generally increases with increasing $\bar{x}_{\rm{HI}}$, following the increasing bias of the cosmic HII regions. As is the case for 21cm, the strongest cross signal occurs when the IGM is colder than the CMB, providing a large contrast between the neutral regions and the ionized regions which host LAEs. We also vary the topology of reionization and the epoch of X-ray heating. The cross-correlation during the first half of reionization is sensitive to these topologies, and could thus be used to constrain them.

[56]  arXiv:2004.10104 [pdf, other]

Title: Does modified gravity predict fast stellar bars in spiral galaxies?

Authors: Neda Ghafourian, Mahmood Roshan, Shahram Abbassi

Comments: Accepted for publication in ApJ

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

The evolution of disk galaxies in modified gravity is studied by using high-resolution N-body simulations. More specifically, we use the weak field limit of two modified gravity theories, i.e., nonlocal gravity (NLG) and scalar-tensor-vector gravity known as MOG, and ignore the existence of dark matter halo. On the other hand, we construct the same models in the standard dark matter model and compare their dynamics with the galactic models in modified gravity. It turns out that there are serious differences between galactic models in these different viewpoints. For example, we explicitly show that the galactic models in modified gravity, host faster bars compared to the dark matter case. On the other hand, final stellar bars are weaker in modified gravity. These facts are not new and have already been reported in our previous simulations for exponential galactic models. Therefore, our main purpose in this study is to show that the above-mentioned differences, with emphasis on the speed of the bars, are independent of the initial density profile of the adopted disk/halo. To do so, we employ different profiles for the disk and halo and show that the results remain qualitatively independent of the initial galactic models. Moreover, a more accurate method has been used to quantify the kinematic properties of the stellar bar. Our results imply that contrary to the dark matter models, bars in modified gravity are fast rotators which never leave the fast-bar region until the end of the simulation.

[57]  arXiv:2004.10105 [pdf, other]

Title: Probing the magnetic field in the GW170817 outflow using H.E.S.S. observations

Authors: H.E.S.S. Collaboration: H. Abdalla, R. Adam, F. Aharonian, F. Ait Benkhali, E.O. Angüner, M. Arakawa, C. Arcaro, C. Armand, H. Ashkar, M. Backes, V. Barbosa-Martins, M. Barnard, Y. Becherini, D. Berge, K. Bernlöhr, R. Blackwell, M. Böttcher, C. Boisson, J. Bolmont, S. Bonnefoy, J. Bregeon, M. Breuhaus, F. Brun, P. Brun, M. Bryan, M. Büchele, T. Bulik, T. Bylund, M. Capasso, S. Caroff, A. Carosi, S. Casanova, M. Cerruti, T. Chand, S. Chandra, A. Chen, S. Colafrancesco, M. Curyło, I.D. Davids, C. Deil, J. Devin, P. deWilt, L. Dirson, A. Djannati-Ataï, A. Dmytriiev, A. Donath, V. Doroshenko, L.O'C. Drury, J. Dyks, K. Egberts, G. Emery, J.-P. Ernenwein, S. Eschbach, K. Feijen, S. Fegan, A. Fiasson, G. Fontaine, S. Funk, M. Füßling, S. Gabici, Y.A. Gallant, et al. (164 additional authors not shown)

Comments: 8 pages, 2 figures, 1 table

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

The detection of the first electromagnetic counterpart to the binary neutron star (BNS) merger remnant GW170817 established the connection between short $\gamma$-ray bursts and BNS mergers. It also confirmed the forging of heavy elements in the ejecta (a so-called kilonova) via the r-process nucleosynthesis. The appearance of non-thermal radio and X-ray emission, as well as the brightening, which lasted more than 100 days, were somewhat unexpected. Current theoretical models attempt to explain this temporal behavior as either originating from a relativistic off-axis jet or a kilonova-like outflow. In either scenario, there is some ambiguity regarding how much energy is transported in the non-thermal electrons versus the magnetic field of the emission region. Combining the VLA (radio) and Chandra (X-ray) measurements with observations in the GeV-TeV domain can help break this ambiguity, almost independently of the assumed origin of the emission. Here we report for the first time on deep H.E.S.S. observations of GW170817 / GRB 170817A between 124 and 272 days after the BNS merger with the full H.E.S.S. array of telescopes, as well as on an updated analysis of the prompt (<5 days) observations with the upgraded H.E.S.S. phase-I telescopes. We discuss implications of the H.E.S.S. measurement for the magnetic field in the context of different source scenarios.

[58]  arXiv:2004.10106 [pdf, other]

Title: Information content of JWST-NIRSPEC transmission spectra of warm Neptunes

Authors: Andrea Guzmán Mesa, Daniel Kitzmann, Chloe Fisher, Adam Burgasser, J.H. Hoeijmakers, Pablo Márquez-Neila, Simon Grimm, Avi Mandell, Raphael Sznitman, Kevin Heng

Comments: 21 pages, 17 figures, 3 tables

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

Warm Neptunes offer a rich opportunity for understanding exo-atmospheric chemistry. With the upcoming James Webb Space Telescope (JWST), there is a need to elucidate the balance between investments in telescope time versus scientific yield. We use the supervised machine learning method of the random forest to perform an information content analysis on a 11-parameter model of transmission spectra from the various NIRSpec modes. The three bluest medium-resolution NIRSpec modes (0.7 - 1.27 microns, 0.97 - 1.84 microns, 1.66 - 3.07 microns) are insensitive to the presence of CO. The reddest medium-resolution mode (2.87 - 5.10 microns) is sensitive to all of the molecules assumed in our model: CO, CO2, CH4, C2H2, H2O, HCN and NH3. It competes effectively with the three bluest modes on the information encoded on cloud abundance and particle size. It is also competitive with the low-resolution prism mode (0.6 - 5.3 microns) on the inference of every parameter except for the temperature and ammonia abundance. We recommend astronomers to use the reddest medium-resolution NIRSpec mode for studying the atmospheric chemistry of 800-1200 K warm Neptunes; its corresponding high-resolution counterpart offers diminishing returns. We compare our findings to previous JWST information content analyses that favor the blue orders, and suggest that the reliance on chemical equilibrium could lead to biased outcomes if this assumption does not apply. A simple, pressure-independent diagnostic for identifying chemical disequilibrium is proposed based on measuring the abundances of H2O, CO and CO2.

[59]  arXiv:2004.10123 [pdf, ps, other]

Title: The radio properties of the OH megamaser galaxy IRAS 02524+2046

Authors: Hao Peng, Zhongzu Wu, Bo Zhang, Yongjun Chen, Xingwu Zheng, Dongrong Jiang, Zhiqiang Shen, Xi Chen, Sotnikova, Yu. V

Comments: 13pages,9 figures, accepted by A&A

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

We present results from VLBI observations of continuum and OH line emission in IRAS 02524+2046 and also arcsecond-scale radio properties of this galaxy using VLA archive data. We found that there is no significant detection of radio continuum emission from VLBI observations. The arcsecond-scale radio images of this source show no clear extended emission, the total radio flux density at L and C band are around 2.9 mJy and 1.0 mJy respectively, which indicate a steep radio spectral index between the two band. Steep spectral index, low brightness temperature and high $q$-ratio (the FIR to the radio flux density), which are three critical indicators in classification of radio activity in the nuclei of galaxies, are all consistent with the classification of this source as a starburst galaxy from its optical spectrum. The high-resolution line profile show that both of \textbf{the 1665 and 1667 MHz OH maser} line have been detected which show three and two clear components respectively. The channel maps show that the maser emission are distributed in a region $\sim$ 210 pc $\times$ 90 pc, the detected maser components at different region show similar double spectral feature, which might be an evidence that this galaxy is at a stage of major merger as seen from the optical morphology.

[60]  arXiv:2004.10133 [pdf, other]

Title: Heavy element evolution in the inner regions of the Milky Way

Authors: F. Matteucci, A. Vasini, V. Grisoni, M. Schultheis

Comments: 10 pages, 9 figures

Journal-ref: MNRAS 2020

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

We present results for the evolution of the abundances of heavy elements (O, Mg, Al, Si, K, Ca, Cr, Mn, Ni and Fe) in the inner Galactic regions ($R_{GC} < 4$kpc). We adopt a detailed chemical evolution model already tested for the Galactic bulge and compare the results with APOGEE data. We start with a set of yields from the literature which are considered the best to reproduce the abundance patterns in the solar vicinity. We find that in general the predicted trends nicely reproduce the data but in some cases either the trend or the absolute values of the predicted abundances need to be corrected, even by large factors, in order to reach the best agreement. We suggest how the current stellar yields should be modified to reproduce the data and we discuss whether such corrections are reasonable in the light of the current knowledge of stellar nucleosynthesis. However, we also critically discuss the observations. Our results suggest that Si, Ca, Cr and Ni are the elements for which the required corrections are the smallest, while for Mg and Al moderate modifications are necessary. On the other hand, O and K need the largest corrections to reproduce the observed patterns, a conclusion already reached for solar vicinity abundance patterns, with the exception of oxygen. For Mn we apply corrections already suggested in previous works. \end{abstract}

[61]  arXiv:2004.10155 [pdf, other]

Title: Scale Symmetry in the Universe

Authors: Jose Gaite

Comments: 19 pages, 5 figures

Journal-ref: Symmetry 2020, 12, 597

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

Scale symmetry is a fundamental symmetry of physics that seems however not to be fully realized in the universe. Here, we focus on the astronomical scales ruled by gravity, where scale symmetry holds and gives rise to a truly scale invariant distribution of matter, namely it gives rise to a fractal geometry. A suitable explanation of the features of the fractal cosmic mass distribution is provided by the nonlinear Poisson--Boltzmann--Emden equation. An alternative interpretation of this equation is connected with theories of quantum gravity. We study the fractal solutions of the equation and connect them with the statistical theory of random multiplicative cascades, which originated in the theory of fluid turbulence. The type of multifractal mass distributions so obtained agrees with results from the analysis of cosmological simulations and of observations of the galaxy distribution.

[62]  arXiv:2004.10160 [pdf, other]

Title: Determination of size, albedo and thermal inertia of 10 Vesta family asteroids with WISE/NEOWISE observations

Authors: Haoxuan Jiang, Jianghui Ji, Liangliang Yu

Comments: 29 pages, 40 figures, accepted for publication in AJ

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

In this work, we investigate the size, thermal inertia, surface roughness and geometric albedo of 10 Vesta family asteroids by using the Advanced Thermophysical Model (ATPM), based on the thermal infrared data acquired by mainly NASA's Wide-field Infrared Survey Explorer (WISE). Here we show that the average thermal inertia and geometric albedo of the investigated Vesta family members are 42 $\rm J m^{-2} s^{-1/2} K^{-1}$ and 0.314, respectively, where the derived effective diameters are less than 10 km. Moreover, the family members have a relatively low roughness fraction on their surfaces. The similarity in thermal inertia and geometric albedo among the V-type Vesta family member may reveal their close connection in the origin and evolution. As the fragments of the cratering event of Vesta, the family members may have undergone similar evolution process, thereby leading to very close thermal properties. Finally, we estimate their regolith grain sizes with different volume filling factors.

[63]  arXiv:2004.10164 [pdf, other]

Title: Spectroscopy of the first resolved strongly lensed Type Ia supernova iPTF16geu

Authors: J. Johansson, A. Goobar, S. H. Price, A. Sagués Carracedo, L. Della Bruna, P. E. Nugent, S. Dhawan, E. Mörtsell, S. Papadogiannakis, R. Amanullah, D. Goldstein, S. B. Cenko, K. De, A. Dugas, M. M. Kasliwal, S. R. Kulkarni, R. Lunnan

Comments: 10 pages, 10 figures. Comments are welcome!

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

We report the results from spectroscopic observations of the multiple images of the strongly lensed Type Ia supernova (SN Ia), iPTF16geu, obtained with ground based telescopes and the Hubble Space Telescope (HST). From a single epoch of slitless spectroscopy with HST, we can resolve spectra of individual lensed supernova images for the first time. This allows us to perform an independent measurement of the time-delay between the two brightest images, $\Delta t = 1.4 \pm 5.0$ days, which is consistent with the time-delay measured from the light-curves.
We also present measurements of narrow emission and absorption lines characterizing the interstellar medium in the host galaxy at z=0.4087, as well as in the foreground lensing galaxy at z=0.2163. We detect strong Na ID absorption in the host galaxy, indicating that iPTF16geu belongs to a subclass of SNe Ia displaying "anomalously" large Na ID column densities in comparison to the amount of dust extinction derived from their light curves. For the deflecting galaxy, we refine the measurement of the velocity dispersion, $\sigma = 129 \pm 4$ km/s, which significantly constrains the lens model.
Since the time-delay between the SN images is negligible, we can use unresolved ground based spectroscopy, boosted by a factor ~70 from lensing magnification, to study the properties of a high-z SN Ia with unprecedented signal-to-noise ratio. The spectral properties of the supernova, such as pseudo-Equivalent widths of several absorption features and velocities of the Si II-line indicate that iPTF16geu, besides being lensed, is a normal SN Ia, indistinguishable from well-studied ones in the local universe, providing support for the use of SNe Ia in precision cosmology. We do not detect any significant deviations of the SN spectral energy distribution from microlensing of the SN photosphere by stars and compact objects in the lensing galaxy.

[64]  arXiv:2004.10193 [pdf, other]

Title: Limiting the shock acceleration of cosmic-ray protons in the ICM

Authors: Denis Wittor, Franco Vazza, Dongsu Ryu, Hyesung Kang

Comments: published by Monthly Notices of the Royal Astronomical Society: Letters, 6 pages, 4 figures

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

Observations of large-scale radio emissions prove the existence of shock accelerated cosmic-ray electrons in galaxy clusters, while the lack of detected $\gamma$-rays limits the acceleration of cosmic-ray protons in galaxy clusters. This challenges our understanding of how diffusive shock acceleration works. In this work, we couple the most updated recipes for shock acceleration in the intracluster medium to state-of-the-art magneto-hydrodynamical simulations of massive galaxy clusters. Furthermore, we use passive tracer particles to follow the evolution of accelerated cosmic-rays. We show that when the interplay between magnetic field topology and the feedback from accelerated cosmic rays is taken into account, the latest developments of particle acceleration theory give results which are compatible with observational constraints.

Cross-lists for Wed, 22 Apr 20

[65]  arXiv:2004.09497 (cross-list from hep-ph) [pdf, ps, other]

Title: Measurement of TeV dark particles due to decay of heavy dark matter in the earth core at IceCube

Authors: Ye Xu

Comments: 10 pages, 4 figures.arXiv admin note: text overlap with arXiv:1904.12266, arXiv:1910.11158

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

In the present paper, it is assumed that there exist two species of dark matter: a heavy dark matter particle (HDM) with the mass of O(TeV) which is generated in early universe and a lighter dark matter particle (LDM) which is a relativistic product due to the decay of HDM. HDMs, captured by the earth, decay to high energy LDMs, and these particles can be measured by km$^3$ neutrino telescopes, like the IceCube detector. A $Z^{\prime}$ portal dark matter model is taken for LDMs to interact with nuclei via a neutral current interaction mediated by a heavy gauge boson $Z^{\prime}$. With the different lifetimes of decay of HDMs and Z$^{\prime}$ masses, the event rates of LDMs, measured by IceCube, are evaluated in the energy range between 1 TeV and 100 TeV. According to the IceCube data, the upper limit for LDM fluxes is estimated at 90\% C.L. at IceCube. Finally, it is proved that LDMs could be directly detected in the energy range betwen O(1TeV) and O(10TeV) at IceCube with $m_{Z^{\prime}} \lesssim 500 GeV$ and $\tau_{\phi} \lesssim 10^{21}$ s.

[66]  arXiv:2004.09511 (cross-list from hep-ph) [pdf, other]

Title: Sterile Neutrino Dark Matter in Left-Right Theories

Authors: Jeff A. Dror, David Dunsky, Lawrence J. Hall, Keisuke Harigaya

Comments: 30 pages, 5 figures

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

$SU(2)_L \times SU(2)_R$ gauge symmetry requires three right-handed neutrinos ($ N _i $), one of which, $N_1$, can be sufficiently stable to be dark matter. In the early universe, $ W _R $ exchange with the Standard Model thermal bath keeps the right-handed neutrinos in thermal equilibrium at high temperatures. $N_1$ can make up all of dark matter if they freeze-out while relativistic and are mildly diluted by subsequent decays of a long-lived and heavier right-handed neutrino, $N_2$. We systematically study this parameter space, constraining the symmetry breaking scale of $SU(2)_R$ and the mass of $N_1$ to a triangle in the $(v_R,M_1)$ plane, with $v_R = (10^6 - 3 \times 10^{12})$ GeV and $M_1 = (2\, {\rm keV} - 1 \, {\rm MeV)}$. Much of this triangle can be probed by signals of warm dark matter, especially if leptogenesis from $N_2$ decay yields the observed baryon asymmetry. The minimal value of $v_R$ is increased to $10^8 \, {\rm GeV}$ for doublet breaking of $SU(2)_R$, and further to $10^9 \, {\rm GeV}$ if leptogenesis occurs via $N_2$ decay, while the upper bound on $M_1$ is reduced to 100 keV. In addition, there is a component of hot $N_1$ dark matter resulting from the late decay of $N_2 \rightarrow N_1 \ell^+ \ell^-$ that can be probed by future cosmic microwave background observations. Interestingly, the range of $v_R$ allows both precision gauge coupling unification and the Higgs Parity understanding of the vanishing of the Standard Model Higgs quartic at scale $v_R$. Finally, we study freeze-in production of $N_1$ dark matter via the $W_R$ interaction, which allows a much wider range of $(v_R,M_1)$.

[67]  arXiv:2004.09524 (cross-list from gr-qc) [pdf, other]

Title: Physics-inspired deep learning to characterize the signal manifold of quasi-circular, spinning, non-precessing binary black hole mergers

Authors: Asad Khan, E. A. Huerta, Arnav Das

Comments: 21 pages, 10 figures, 1 appendix, 1 Interactive visualization at this https URL

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

The spin distribution of binary black hole mergers contains key information concerning the formation channels of these objects, and the astrophysical environments where they form, evolve and coalesce. To quantify the suitability of deep learning to characterize the signal manifold of quasi-circular, spinning, non-precessing binary black hole mergers, we introduce a modified version of WaveNet trained with a novel optimization scheme that incorporates general relativistic constraints of the spin properties of astrophysical black holes. The neural network model is trained, validated and tested with 1.5 million $\ell=|m|=2$ waveforms generated within the regime of validity of NRHybSur3dq8, i.e., mass-ratios $q\leq8$ and individual black hole spins $ | s^z_{\{1,\,2\}} | \leq 0.8$. Using this neural network model, we quantify how accurately we can infer the astrophysical parameters of black hole mergers in the absence of noise. We do this by computing the overlap between waveforms in the testing data set and the corresponding signals whose mass-ratio and individual spins are predicted by our neural network. We find that the convergence of high performance computing and physics-inspired optimization algorithms enable an accurate reconstruction of the mass-ratio and individual spins of binary black hole mergers across the parameter space under consideration. This is a significant step towards an informed utilization of physics-inspired deep learning models to reconstruct the spin distribution of binary black hole mergers in realistic detection scenarios.

[68]  arXiv:2004.09526 (cross-list from hep-th) [pdf, ps, other]

Title: Non-canonical kinetic structures in the swampland

Authors: Adam R. Solomon, Mark Trodden

Comments: 16+3 pages

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

We consider how the swampland criteria might be applied to models in which scalar fields have nontrivial kinetic terms, particularly in the context of $P(\phi,X)$ theories, popularly used in approaches to inflation, to its alternatives, and to the problem of late-time cosmic acceleration. By embedding such theories in canonical multi-field models, from which the original theory emerges as a low-energy effective field theory, we derive swampland constraints, and study the circumstances under which these might be evaded while preserving cosmologically interesting phenomenology. We further demonstrate how these successes are tied to the phenomenon of turning in field space in the multi-field picture. We study both the general problem and specific examples of particular interest, such as DBI inflation.

[69]  arXiv:2004.09539 (cross-list from hep-ph) [pdf, other]

Title: Kinetic Heating from Contact Interactions with Relativistic Targets: Electrons Capture Dark Matter in Neutron Stars

Authors: Aniket Joglekar, Nirmal Raj, Philip Tanedo, Hai-Bo Yu

Comments: 28 pages + appendices, 15 figures

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

Dark matter can capture in neutron stars from scattering off ultra-relativistic electrons. We present a method to calculate the capture rate on degenerate targets with ultra-relativistic momenta in a compact astronomical object. Our treatment accounts for the target momentum and the Fermi degeneracy of the system. We derive scaling relations for scattering with relativistic targets and confirm consistency with the non-relativistic limit and Lorentz invariance. The potential observation of kinetic heating of neutron stars has a larger discovery reach for dark matter--lepton interactions than conventional terrestrial direct detection experiments. We map this reach onto a set of bosonic and fermionic effective contact interactions between dark matter and leptons as well as nucleons. This completes the study of spin-0 and spin-1/2 dark matter kinetic heating of neutron stars through contact operators with Standard Model fermions up to dimension-6. Our method is generalizable to dark matter scattering in any degenerate medium where the Pauli exclusion principle leads to relativistic targets with a constrained phase space for scattering.

[70]  arXiv:2004.09587 (cross-list from hep-th) [pdf, other]

Title: On the Symmetries of Cosmological Perturbations

Authors: Daniel Green, Enrico Pajer

Comments: 33 pages

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

The space of inflationary models is vast, containing wide varieties of mechanisms, symmetries, and spectra of particles. Consequently, the space of observational signatures is similarly complex. Hence, it is natural to look for boundaries of the space of models and their signatures. In this paper, we explore the possible symmetries associated with the primordial cosmological perturbations and their correlators in the asymptotic future. Assuming the observed homogeneity, isotropy and (approximate) scale invariance, we prove three main results. First, correlation functions of scalar metric fluctuations are uniquely characterized by soft theorems and are free from ambiguity under field redefinitions. Second, whatever the particle content and interactions, when the standard soft theorems apply, invariance under de Sitter boosts (linearly realized conformal invariance) is only possible if all connected correlators vanish identically, i.e. if the theory is free. Third, conformal invariance is the largest set of linearly realized (bosonic) symmetries of the correlators of any single scalar, irrespectively of any soft theorems or particle content.

[71]  arXiv:2004.09706 (cross-list from physics.ins-det) [pdf, other]

Title: Development of a Negative Ion Micro TPC Detector with SF$_{6}$ Gas for the Directional Dark Matter Search

Authors: T. Ikeda, T. Shimada, H. Ishiura, K. D. Nakamura, T. Nakamura, K. Miuchi

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

A negative ion micro time projection chamber (NI$\mu$TPC) was developed and its performance studied. An NI$\mu$TPC is a novel technology that enables the measurement of absolute $z$ coordinates for self-triggering TPCs. This technology provides full-fiducialization analysis, which is not possible with conventional gaseous TPCs, and is useful for directional dark matter searches in terms of background rejection and the improvement of the angular resolution. The developed NI$\mu$TPC prototype had a detection volume of 12.8 $\times$ 25.6 $\times$ 144 mm$^{3}$. The absolute $z$ coordinate was determined with a location accuracy of 16 mm using minority carrieres of SF$_{5}^{-}$. Simultaneously, there was a successful reconstruction of the three-dimensional (3D) tracks with a spatial resolution of 130 $\mu\rm{m}$. This is the first demonstration of 3D tracking with the detection of absolute $z$ coordinates, and it is an important step in improving the sensitivity of directional dark matter searches.

[72]  arXiv:2004.10025 (cross-list from hep-th) [pdf, other]

Title: Dark Energy, Dark Matter and Baryogenesis from a Model of a Complex Axion Field

Authors: Robert Brandenberger, Jürg Fröhlich (McGill Univ. and ETH Zurich)

Comments: 11 pages, 4 figures

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

We introduce and study a model designed to simultaneously shed light on the mysteries connected with Baryogenesis, Dark Matter and Dark Energy. The model describes a self-interacting complex axion field whose imaginary part, a pseudo-scalar axion, couples to the instanton density of gauge fields including the hypermagnetic field. This coupling may give rise to baryogenesis in the early universe. After tracing out the gauge and matter degrees of freedom, a non-trivial effective potential for the angular component of the axion field is obtained. It is proposed that oscillations of this component around a minimum of its effective potential can be interpreted as Dark Matter. The absolute value of the axion field rolls slowly towards $0$. At late times, it can give rise to Dark Energy.

[73]  arXiv:2004.10036 (cross-list from hep-ph) [pdf, other]

Title: Constraint on Vector Coherent Oscillation Dark Matter with Kinetic Function

Authors: Kazunori Nakayama

Comments: 21 pages, 4 figures

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

A spatially uniform vector condensate can be formed during inflation if the vector boson is coupled to the inflaton through nontrivial kinetic function. The coherent oscillation of such a massive vector boson is a dark matter candidate. In this paper we consider the case where the vector boson energy density increases during inflation and show that the curvature/isocurvature perturbation gives stringent constraint on this scenario.

[74]  arXiv:2004.10148 (cross-list from hep-ph) [pdf, other]

Title: The gravitational waves from the collapsing domain walls in the complex singlet model

Authors: Ning Chen, Tong Li, Yongcheng Wu

Comments: 21 pages, 4 figures

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

We study the CP domain walls and the consequent gravitational waves induced by the spontaneous breaking of the CP symmetry in the complex singlet extension to the Standard Model. We impose the constraints from the unitarity, stability and the global minimal of the vacuum solutions on the model parameter space. The CP domain wall profiles and tensions are obtained by numerically solving the relevant field equations. The explicit CP violation terms are then introduced to the potential as biased terms to make the domain walls unstable and collapse, The BBN bound on the magnitude of the energy bias is taken into account. To achieve sufficiently strong gravitational wave signals, the domain wall tension $\sigma$ is required to be at least $\sigma/{\rm TeV}^3 \sim \mathcal{O}(10^3)$. We find that the gravitational wave spectrum can be probed in the future SKA and/or DECIGO programs, when the typical mass scale is at least $\sim \mathcal{O}(10)$ TeV and the explicit CP violation terms are as small as $\mathcal{O}(10^{-29}) - \mathcal{O}(10^{-27}) $. The gravitational waves from collapsing domain walls thus provide a complementarity to the probe of extremely small CP violation at high-energy scale.

Replacements for Wed, 22 Apr 20

[75]  arXiv:1503.04436 (replaced) [pdf, other]

Title: Hint at an axion-like particle from the redshift dependence of blazar spectra

Authors: Giorgio Galanti, Marco Roncadelli, Alessandro De Angelis, Giovanni F. Bignami

Comments: 13 pages, 14 figures. This version matches the published paper: MNRAS 493, 1553 (2020)

Journal-ref: MNRAS 493, 1553 (2020)

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

[76]  arXiv:1810.04172 (replaced) [pdf, other]

Title: Probing Cosmic Strings with Gravitational-Wave Fringe

Authors: Sunghoon Jung, TaeHun Kim

Comments: Discussions added and improved; conclusion neutralized; figures revised. 22 pages, 4 figures

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

[77]  arXiv:1812.08356 (replaced) [pdf, other]

Title: Dark Matter Distribution of Four Low-z Clusters of Galaxies

Authors: Jacqueline McCleary, Ian dell'Antonio, Anja von der Linden

Comments: 29 pages, 18 figures

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

[78]  arXiv:1906.00502 (replaced) [pdf, other]

Title: Description of atypical bursts seen slightly off-axis

Authors: N. Fraija, F. De Colle, P. Veres, S. Dichiara, R. Barniol Duran, A.C. Caligula do E. S. Pedreira, A. Galvan-Gamez, B. Betancourt Kamenetskaia

Comments: 24 pages, 15 figures. Accepted for publication in ApJ

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

[79]  arXiv:1907.01485 (replaced) [pdf, other]

Title: A transition from parabolic to conical shape as a common effect in nearby AGN jets

Authors: Y. Y. Kovalev (Lebedev, MIPT, MPIfR), A. B. Pushkarev (CrAO, Lebedev), E. E. Nokhrina (MIPT), A. V. Plavin (Lebedev, MIPT), V. S. Beskin (Lebedev, MIPT), A. Chernoglazov (Lebedev, MIPT), M. L. Lister (Purdue U.), T. Savolainen (Aalto U., MPIfR)

Comments: 18 pages; electronic table 3 is available from the preprint source; text, some figures and tables are revised; accepted by MNRAS

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

[80]  arXiv:1907.02795 (replaced) [pdf, other]

Title: A statistical study of long-term evolution of coronal hole properties as observed by SDO

Authors: Stephan G. Heinemann, Veronika Jerčić, Manuela Temmer, Stefan J. Hofmeister, Mateja Dumbović, Susanne Vennerstroem, Giuliana Verbanac, Astrid M. Veronig

Comments: Accepted at A&A

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

[81]  arXiv:1907.07787 (replaced) [pdf, other]

Title: Constraining the astrophysics and cosmology from 21cm tomography using deep learning with the SKA

Authors: Sultan Hassan (NMSU/UWC), Sambatra Andrianomena (SARAO/UWC), Caitlin Doughty (NMSU)

Comments: Accepted for publication in MNRAS

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

[82]  arXiv:1907.09970 (replaced) [pdf, other]

Title: Static self-gravitating Newtonian elastic balls

Authors: Artur Alho, Simone Calogero

Comments: 30 pages, 2 figures. The order of presentation of the results and the notation have been changed considerably to improve the reading flow of the article. Some assumptions and theorems have been reformulated in a more clear way and several new remarks have been added

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

[83]  arXiv:1907.12575 (replaced) [pdf, other]

Title: A Parametric model for the shapes of black-hole shadows in non-Kerr spacetimes

Authors: Lia Medeiros, Dimitrios Psaltis, Feryal Özel

Comments: New figure added, new simulations run correcting typo in previous work, accepted to ApJ

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

[84]  arXiv:1909.04338 (replaced) [pdf, ps, other]

Title: A new test of the weak equivalence principle using the observations of binary neutron star merger GW170817

Authors: Lulu Yao, Zonghua Zhao, Yu Han, Jingbo Wang, Tong Liu, Molin Liu

Comments: 11 pages, 4 figures, 6 tables, major revision

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

[85]  arXiv:1909.05269 (replaced) [pdf, other]

Title: First Gaia dynamical model of the Milky Way disc with six phase space coordinates: a test for galaxy dynamics

Authors: Maria Selina Nitschai, Michele Cappellari, Nadine Neumayer

Comments: 10 pages, 4 figures, 1 table. Accepted for publication in MNRAS

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

[86]  arXiv:1911.04197 (replaced) [pdf, other]

Title: Sunquakes of Solar Cycle 24

Authors: I.N. Sharykin, A.G. Kosovichev

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

[87]  arXiv:1911.05765 (replaced) [pdf, other]

Title: Constraints on the Engines of Fast Radio Bursts

Authors: Ben Margalit, Brian D. Metzger, Lorenzo Sironi

Comments: MNRAS accepted version

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

[88]  arXiv:1911.09622 (replaced) [pdf, ps, other]

Title: The Unusual Broadband X-ray Spectral Variability of NGC 1313 X-1 seen with XMM$-$Newton, Chandra and NuSTAR

Authors: D. J. Walton, C. Pinto, M. Nowak, M. Bachetti, R. Sathyaprakash, E. Kara, T. P. Roberts, R. Soria, M. Brightman, C. R. Canizares, H. P. Earnshaw, F. Furst, M. Heida, M. J. Middleton, D. Stern, L. Tao, N. Webb, W. N. Alston, D. Barret, A. C. Fabian, F. A. Harrison, P. Kosec

Comments: 18 pages, 7 figures, accepted for publication in MNRAS

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

[89]  arXiv:1911.10542 (replaced) [pdf, other]

Title: The running curvaton

Authors: Lei-Hua Liu, Wu-Long Xu

Comments: To be published in Chinese Physics C

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)

[90]  arXiv:1912.06104 (replaced) [pdf, other]

Title: Probing cosmological fields with gravitational wave oscillations

Authors: Jose Beltrán Jiménez, Jose María Ezquiaga, Lavinia Heisenberg

Comments: 36 pages, 9 figures. Matches JCAP version

Journal-ref: JCAP 04 (2020) 027

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

[91]  arXiv:1912.07657 (replaced) [pdf, other]

Title: Time-dependence of the astrophysical stochastic gravitational wave background

Authors: Suvodip Mukherjee, Joseph Silk

Comments: 10 pages, 5 figures. A typographical error in the caption of Fig. 5 is corrected

Journal-ref: MNRAS, Volume 491, Issue 4, February 2020, Pages 4690

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

[92]  arXiv:1912.09483 (replaced) [pdf, other]

Title: Soliton Random Walk and the Cluster-Stripping Problem in Ultralight Dark Matter

Authors: Hsi-Yu Schive, Tzihong Chiueh, Tom Broadhurst

Comments: Accepted for publication in Phys. Rev. Lett. 6 pages, 4 figures

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

[93]  arXiv:2001.06021 (replaced) [pdf, other]

Title: Reionization with galaxies and active galactic nuclei

Authors: Pratika Dayal, Marta Volonteri, Tirthankar Roy Choudhury, Raffaella Schneider, Maxime Trebitsch, Nickolay Y. Gnedin, Hakim Atek, Michaela Hirschmann, Amy Reines

Comments: Accepted to MNRAS

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

[94]  arXiv:2001.07182 (replaced) [pdf, ps, other]

Title: Could quasar lensing time delays hint to a core component in halos, instead of H0 tension?

Authors: Kfir Blum, Emanuele Castorina, Marko Simonović

Comments: 11 pages, 4 figures. v3: added comparison to stellar kinematics constraints, fixed typo in Fig.3, dialed down reference to DM with respect to the core structure; match journal version

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

[95]  arXiv:2001.10465 (replaced) [pdf, ps, other]

Title: The Atacama Cosmology Telescope: Constraints on Cosmic Birefringence

Authors: Toshiya Namikawa, Yilun Guan, Omar Darwish, Blake D. Sherwin, Simone Aiola, Nicholas Battaglia, James A. Beall, Daniel T. Becker, J. Richard Bond, Erminia Calabrese, Grace E. Chesmore, Steve K. Choi, Mark J. Devlin, Joanna Dunkley, Rolando Dünner, Anna E. Fox, Patricio A. Gallardo, Vera Gluscevic, Dongwon Han, Matthew Hasselfield, Gene C. Hilton, Adam D. Hincks, Renée Hložek, Johannes Hubmayr, Kevin Huffenberger, John P. Hughes, Brian J. Koopman, Arthur Kosowsky, Thibaut Louis, Marius Lungu, Amanda MacInnis, Mathew S. Madhavacheril, Maya Mallaby-Kay, Loïc Maurin, Jeffrey McMahon, Kavilan Moodley, Sigurd Naess, Federico Nati, Laura B. Newburgh, John P. Nibarger, Michael D. Niemack, Lyman A. Page, Frank J. Qu, Naomi Robertson, Alessandro Schillaci, Neelima Sehgal, Cristóbal Sifón, et al. (7 additional authors not shown)

Comments: 18 pages, 3 figures, Accepted for publication in PRD

Journal-ref: Phys. Rev. D 101, 083527 (2020)

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

[96]  arXiv:2002.00036 (replaced) [pdf, other]

Title: Degenerate Sub-keV Fermion Dark Matter from a Solution to the Hubble Tension

Authors: Gongjun Choi, Motoo Suzuki, Tsutomu T. Yanagida

Comments: 7 pages, 2 figures, version published in PRD

Journal-ref: Phys. Rev. D 101, 075031 (2020)

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

[97]  arXiv:2002.08746 (replaced) [pdf, other]

Title: A census of main-sequence interactions in the Multiple Star Catalog

Authors: Adrian S. Hamers

Comments: Accepted for publication in MNRAS. 16 pages, 13 figures

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

[98]  arXiv:2002.11778 (replaced) [pdf, other]

Title: On Spin Dependence of the Fundamental Plane of Black Hole Activity

Authors: Caner Unal, Abraham Loeb

Comments: Accepted for publication in MNRAS

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

[99]  arXiv:2003.04848 (replaced) [pdf, ps, other]

Title: On the FRB luminosity function -- II. Event rate density

Authors: Rui Luo, Yunpeng Men, Kejia Lee, Weiyang Wang, D. R. Lorimer, Bing Zhang

Comments: 16 pages, 6 figures, 7 tables, 4 appendixes, minor corrections to match the published version in MNRAS

Journal-ref: MNRAS 494 665 (2020)

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

[100]  arXiv:2003.04905 (replaced) [pdf, other]

Title: Constraining the reionization history using deep learning from 21cm tomography with the Square Kilometre Array

Authors: Tumelo Mangena (UWC/SARAO), Sultan Hassan (NMSU/UWC), Mario G. Santos (UWC/SARAO)

Comments: Accepted for publication in MNRAS

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

[101]  arXiv:2004.04177 (replaced) [pdf, other]

Title: Inpainting via Generative Adversarial Networks for CMB data analysis

Authors: Alireza Vafaei Sadr, Farida Farsian

Comments: 19 pages, 21 figures. Prepared for submission to JCAP. All codes will be published after acceptance

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Computer Vision and Pattern Recognition (cs.CV); Machine Learning (cs.LG); Computation (stat.CO)

[102]  arXiv:2004.04280 (replaced) [pdf]

Title: Positron Processes in the Sun

Authors: Nat Gopalswamy

Comments: 12 pages, 6 figures, 1 table, to appear in Atoms

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

[103]  arXiv:2004.06102 (replaced) [pdf, other]

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

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

Comments: 2 figures, 1 table

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

[104]  arXiv:2004.08397 (replaced) [pdf, other]

Title: The Origin and Evolution of Lyman-alpha Blobs in Cosmological Galaxy Formation Simulations

Authors: Benjamin Kimock, Desika Narayanan, Aaron Smith, Xiangcheng Ma, Robert Feldmann, Daniel Anglés-Alcázar, Volker Bromm, Romeel Dave, James E. Geach, Philip Hopkins, Dušan Kereš

Comments: Submitted to ApJ; comments welcome. 23 pages, 21 figures

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

[105]  arXiv:2004.09288 (replaced) [pdf, other]

Title: An alternative interpretation of GW190412 as a binary black hole merger with a rapidly spinning secondary

Authors: Ilya Mandel, Tassos Fragos

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

[106]  arXiv:2004.09339 (replaced) [pdf, ps, other]

Title: Vacua in novel 4D Eisntein-Gauss-Bonnet Gravity: pathology and instability?

Authors: Fu-Wen Shu

Comments: 6 pages, 1 figure

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

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