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New submissions for Thu, 2 Apr 20

[1]  arXiv:2004.00011 [pdf, other]

Title: Green Bank and Effelsberg Radio Telescope Searches for Axion Dark Matter Conversion in Neutron Star Magnetospheres

Authors: Joshua W. Foster, Yonatan Kahn, Oscar Macias, Zhiquan Sun, Ralph P. Eatough, Vladislav I. Kondratiev, Wendy M. Peters, Christoph Weniger, Benjamin R. Safdi

Comments: 7+20 pages, 2+17 figures, Supplementary Data at this http URL

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

Axion dark matter (DM) may convert to radio-frequency electromagnetic radiation in the strong magnetic fields around neutron stars. The radio signature of such a process would be an ultra-narrow spectral peak at a frequency determined by the mass of the axion particle. We analyze data we collected from the Robert C. Byrd Green Bank Telescope in the L-band and the Effelsberg 100-m Telescope in the L-Band and S-band from a number of sources expected to produce bright signals of axion-photon conversion, including the Galactic Center of the Milky Way and the nearby isolated neutron stars RX J0720.4-3125 and RX J0806.4-4123. We find no evidence for axion DM and are able to set some of the strongest constraints to-date on the existence of axion DM in the highly-motivated mass range between ~5-11 $\mu$eV.

[2]  arXiv:2004.00012 [pdf, other]

Title: Modelling Thermonuclear X-ray Bursts on Accreting Neutron Stars

Authors: Zac Johnston

Comments: PhD Thesis, 105 pages, contains versions of the articles arXiv:1711.03970 and arXiv:1909.07977

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

In low-mass X-ray binaries, the accretion of stellar material onto a neutron star can fuel unstable thermonuclear flashes known as Type I X-ray bursts. Simulating these events using computational models can provide valuable information about the nature of the accreting system. One-dimensional (1D) astrophysics codes with large nuclear reaction networks are the current state-of-the-art for simulating X-ray bursts. These codes can track the evolution of isotopes through thousands of nuclear reaction pathways, to predict the released nuclear energy and final composition of the ashes. In this thesis, I make extensive use of KEPLER, a 1D code at the forefront of these efforts. I first present improvements to the setup and analysis of KEPLER burst models. By accounting for nuclear heating in the initial conditions, I shorten the thermal burn-in time, thereby reducing computational expense and producing more consistent burst trains. To model bursts fueled by transient accretion events, I perform the first such simulations with fully time-dependent accretion rates. Building upon previous efforts to model the "Clocked Burster", GS 1826$-$238, I precompute a grid of 3840 simulations and sample the interpolated results using Markov Chain Monte Carlo (MCMC) methods. By comparing the predictions to multi-epoch observations, I obtain posterior probability distributions for the system parameters. I then extend these MCMC methods to the pure-helium burster, 4U 1820$-$30, using a grid of 168 simulations. Finally, I discuss potential improvements for future studies, to further develop the computational modelling of accreting neutron stars.

[3]  arXiv:2004.00013 [pdf, other]

Title: Variations in fundamental constants at the cosmic dawn

Authors: Laura Lopez-Honorez, Olga Mena, Sergio Palomares-Ruiz, Pablo Villanueva-Domingo, Samuel J. Witte

Comments: 16 pages, 5 figures, 2 tables

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

The observation of space-time variations in fundamental constants would provide strong evidence for the existence of new light degrees of freedom in the theory of Nature. Robustly constraining such scenarios requires exploiting observations that span different scales and probe the state of the Universe at different epochs. In the context of cosmology, both the cosmic microwave background and the Lyman-$\alpha$ forest have proven to be powerful tools capable of constraining variations in electromagnetism, however at the moment there do not exist cosmological probes capable of bridging the gap between recombination and reionization. In the near future, radio telescopes will attempt to measure the 21cm transition of neutral hydrogen during the epochs of reionization and the cosmic dawn (and potentially the tail end of the dark ages); being inherently sensitive to electromagnetic phenomena, these experiments will offer a unique perspective on space-time variations of the fine-structure constant and the electron mass. We show here that large variations in these fundamental constants would produce features on the 21cm power spectrum that may be distinguishable from astrophysical uncertainties. Furthermore, we forecast the sensitivity for the Square Kilometer Array, and show that the 21cm power spectrum may be able to constrain variations at the level of ${\mathcal O}(10^{-3})$.

[4]  arXiv:2004.00014 [pdf, other]

Title: Smaller than expected bright-spot offsets in Spitzer phase curves of the hot Jupiter Qatar-1b

Authors: Dylan Keating, Kevin B. Stevenson, Nicolas B. Cowan, Emily Rauscher, Jacob L. Bean, Taylor Bell, Lisa Dang, Drake Deming, Jean-Michel Désert, Y. Katherina Feng, Jonathan J. Fortney, Tiffany Kataria, Eliza M.-R. Kempton, Nikole Lewis, Michael R. Line, Megan Mansfield, Erin May, Caroline Morley, Adam P. Showman

Comments: 14 pages, 8 figures. Accepted for publication in AJ

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

We present \textit{Spitzer} full-orbit thermal phase curves of the hot Jupiter Qatar-1b, a planet with the same equilibrium temperature---and intermediate surface gravity and orbital period---as the well-studied planets HD 209458b and WASP-43b. We measure secondary eclipse of $0.21 \pm 0.02 \%$ at $3.6~\mu$m and $0.30 \pm 0.02 \%$ at $4.5~\mu$m, corresponding to dayside brightness temperatures of $1542^{+32}_{-31}$~K and $1557^{+35}_{-36}$~K, respectively, consistent with a vertically isothermal dayside. The respective nightside brightness temperatures are $1117^{+76}_{-71}$~K and $1167^{+69}_{-74}$~K, in line with a trend that hot Jupiters all have similar nightside temperatures. We infer a Bond albedo of $0.12_{-0.16}^{+0.14}$ and a moderate day-night heat recirculation efficiency, similar to HD 209458b. General circulation models for HD 209458b and WASP-43b predict that their bright-spots should be shifted east of the substellar point by tens of degrees, and these predictions were previously confirmed with \textit{Spitzer} full-orbit phase curve observations. The phase curves of Qatar-1b are likewise expected to exhibit eastward offsets. Instead, the observed phase curves are consistent with no offset: $11^{\circ}\pm 7^{\circ}$ at $3.6~\mu$m and $-4^{\circ}\pm 7^{\circ}$ at $4.5~\mu$m. The discrepancy in circulation patterns between these three otherwise similar planets points to the importance of secondary parameters like rotation rate and surface gravity, and the presence or absence of clouds, in determining atmospheric conditions on hot Jupiters.

[5]  arXiv:2004.00016 [pdf, other]

Title: Three-Dimensional Kinematic Reconstruction of the Optically-Emitting, High-Velocity, Oxygen-Rich Ejecta of Supernova Remnant N132D

Authors: Charles J. Law, Dan Milisavljevic, Daniel J. Patnaude, Paul P. Plucinsky, Michael D. Gladders, Judy Schmidt, Niharika Sravan, John Banovetz, Hidetoshi Sano, Jordan M. McGraw, George Takahashi, Salvatore Orlando

Comments: 18 pages, 12 figures, accepted for publication in ApJ; 3D animation of N132D can found at: this http URL

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

We present a three-dimensional kinematic reconstruction of the optically-emitting, oxygen-rich ejecta of supernova remnant N132D in the Large Magellanic Cloud. Data were obtained with the 6.5 m Magellan telescope in combination with the IMACS+GISMO instrument and survey [O III] $\lambda\lambda$4959,5007 line emission in a ${\sim}$3$^{\prime}~\times$ 3$^{\prime}$ region centered on N132D. The spatial and spectral resolution of our data enable detailed examination of the optical ejecta structure. The majority of N132D's optically bright oxygen ejecta are arranged in a torus-like geometry tilted approximately 28$^{\circ}$ with respect to the plane of the sky. The torus has a radius of 4.4 pc ($D_{\rm LMC}$/50 kpc), exhibits a blue-shifted radial velocity asymmetry of $-3000$ to $+2300$ km s$^{-1}$, and has a conspicuous break in its circumference. Assuming homologous expansion from the geometric center of O-rich filaments, the average expansion velocity of 1745 km s$^{-1}$ translates to an age since explosion of 2450 $\pm$ 195 yr. A faint, spatially-separated "runaway knot" (RK) with total space velocity of 3650 km s$^{-1}$ is nearly perpendicular to the torus plane and coincident with X-ray emission that is substantially enhanced in Si relative to the LMC and N132D's bulk ejecta. These kinematic and chemical signatures suggest that the RK may have had its origin deep within the progenitor star. Overall, the main shell morphology and high-velocity, Si-enriched components of N132D have remarkable similarity with that of Cassiopeia A, which was the result of a Type IIb supernova explosion. Our results underscore the need for further observations and simulations that can robustly reconcile whether the observed morphology is dominated by explosion dynamics or shaped by interaction with the environment.

[6]  arXiv:2004.00018 [pdf, other]

Title: Purveyors of fine halos. II. Chemodynamical association of halo stars with Milky Way globular clusters

Authors: Michael Hanke, Andreas Koch, Zdenek Prudil, Eva K. Grebel, Ulrich Bastian

Comments: 20 pages (+9 pages of appendices), 39 figures, 4 tables, accepted for publication in A&A

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

We present chemodynamical links between the present-day Milky Way halo field star population and Galactic globular clusters (GCs) using a datasaet that combines information from the $\rm{\it Gaia}$ space mission and the Sloan Digital Sky Survey (SDSS-IV, DR14). Moreover, we incorporated a sample of halo giant stars with a distinct chemical signature (strong CN bandheads) that resembles the light-elements anomaly otherwise only seen in the second generation of GC stellar populations. Using three different tagging techniques, we could successfully establish unique associations between 151 extratidal stars in the neighborhood of eight GCs. In addition, we traced the possible origin of about $62\%$ of the sample of CN-strong giants to their potential host clusters. Several of the involved GCs have been brought into connection with the Gaia-Enceladus and Sequoia merger events. By establishing kinematic and chemical connections between 17 CN-strong stars and their surrounding fields, we could identify co-moving groups of stars at the same [Fe/H] with a possible cluster origin. We found strong evidence that four CN-strong stars and their associates are connected to the Sagittarius stream whilst their tightly confined [Fe/H] may hint to a birth site in M 54. Finally, we provide tentative estimates for the fraction of first-generation cluster stars among all stars lost to the halo. In the immediate cluster vicinity, this value amounts to $50.0\pm16.7\%$ while the associations in the halo field rather imply $80.2_{-5.2}^{+4.9}\%$. We speculate that -- if proven real by spectroscopic follow-up -- the disparity between these numbers could indicate a major contribution of low-mass clusters to the overall number of stars escaped to the halo or, alternatively, point toward a strong mass loss from the first generation during early cluster dissolution. [abridged]

[7]  arXiv:2004.00019 [pdf, other]

Title: A parameter survey of Sgr A* radiative models from GRMHD simulations with self-consistent electron heating

Authors: J. Dexter, A. Jiménez-Rosales, S. M. Ressler, A. Tchekhovskoy, M. Bauböck, P. T. de Zeeuw, F. Eisenhauer, S. von Fellenberg, F. Gao, R. Genzel, S. Gillessen, M. Habibi, T. Ott, J. Stadler, O. Straub, F. Widmann

Comments: 20 pages, 17 figures, MNRAS in press

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

The Galactic center black hole candidate Sgr A* is the best target for studies of low-luminosity accretion physics, including with near-infrared and submillimeter wavelength long baseline interferometry experiments. Here we compare images and spectra generated from a parameter survey of general relativistic MHD simulations to a set of radio to near-infrared observations of Sgr A*. Our models span the limits of weak and strong magnetization and use a range of sub-grid prescriptions for electron heating. We find two classes of scenarios can explain the broad shape of the submillimeter spectral peak and the highly variable near-infrared flaring emission. Weakly magnetized "disk-jet" models where most of the emission is produced near the jet wall, consistent with past work, as well as strongly magnetized (magnetically arrested disk) models where hot electrons are present everywhere. Disk-jet models are strongly depolarized at submillimeter wavelengths as a result of strong Faraday rotation, inconsistent with observations of Sgr A*. We instead favor the strongly magnetized models, which provide a good description of the median and highly variable linear polarization signal. The same models can also explain the observed mean Faraday rotation measure and potentially the polarization signals seen recently in Sgr A* near-infrared flares.

[8]  arXiv:2004.00020 [pdf, other]

Title: Triple common envelope evolution: Circumstellar triples

Authors: Hila Glanz, Hagai B. Perets

Comments: Comments are welcomed

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

The dynamical evolution of triple stellar systems could give rise to the formation of compact binaries and induce binary mergers. Common envelope (CE) evolution, which plays a major role in the evolution of compact binary systems, can similarly play a key role in the evolution of triples. Here we use hydrodynamical simulations coupled with few-body dynamics to provide the first detailed models of triple common envelope (TCE) evolution. We focus on the circumstellar case, where the envelope of an evolved giant engulfs a compact binary orbiting the giant (inner-binary), which then in-spirals into the core of the evolved star. Through our exploratory modeling we find several possible outcomes of such TCE: (1) The merger of the binary inside the third star's envelope; (2) The binary disruption of the in-spiraling binary following its plunge, leading to a chaotic triple dynamics of the stellar-core and the two components of the former disrupted binary. The chaotic evolution typically leads to the in-spiral and merger of at least one of the former binary components with the core, and sometimes to the ejection of the second, or alternatively its further now-binary common-envelope evolution. The in-spiral in TCE leads to overall slower in-spiral, larger mass ejection and the production of more aspherical remnant, compared with a corresponding binary case of similar masses, due to the energy/momentum extraction from the inner-binary. We expect TCE to play a key role in producing various types of stellar-mergers and unique compact binary systems, and potentially induce transient electromagnetic and gravitational-wave sources.

[9]  arXiv:2004.00021 [pdf, other]

Title: Effect of Active Galactic Nuclei Thermal Heating with Radial Dependence on Thermal Stability of Simulated Galaxy Clusters

Authors: Forrest W. Glines, Brian W. O'Shea, G. Mark Voit

Comments: 14 page, 8 figures

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

Observations since the 1970's have revealed the existence of cool-core (CC) clusters, which are galaxy clusters with a central cooling time much shorter than the age of the universe. Both observations and theory suggest that the ambient gas at the centers of galaxy clusters is thermally regulated by a central heating mechanism that suppresses condensation (most likely an active galactic nucleus, or AGN). Previous analytical work has suggested specific configurations of heating kernels that may result in thermal balance and a steady state. To test this hypothesis, we simulated idealized galaxy clusters using the ENZO cosmology code with a spatial heat-input kernel meant to mimic feedback from a central AGN. Thermal heating as a function of radius was injected according to a range of kernels, with global thermal balance enforced at all times. We compare our simulation results with observed entropy profiles from the ACCEPT cluster dataset. Although some heating kernels produced thermally steady galaxy clusters, no kernel was able to produce a steady cluster with a central entropy as low as the central entropies typically observed among CC clusters. The general behavior of the simulations depended on the amount of heating in the inner $10 ~\text{kpc}$, with low central heating leading to central cooling catastrophes, high central heating creating a central convective zone with an inverted entropy gradient, and intermediate heating leading to a flat but elevated entropy core. The simulated clusters enter an unsteady multiphase state on a timescale proportional to the square of the cooling time of the lowest entropy gas in the simulation, with centrally concentrated heating resulting in a steady state lasting for a longer period of time.

[10]  arXiv:2004.00022 [pdf, ps, other]

Title: Absolute dimensions of the unevolved F-type eclipsing binary BT Vulpeculae

Authors: Guillermo Torres (1), Claud H. Sandberg Lacy (2), Francis C. Fekel (3), Matthew W. Muterspaugh (4,5) ((1) Center for Astrophysics, (2) Univ. of Arkansas, (3) Tennessee State Univ., (4) Fairborn Observatory, (5) Columbia State Community College)

Comments: 9 pages in emulateapj format, including tables and figures. Accepted for publication in The Astrophysical Journal

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

We report extensive differential V-band photometry and high-resolution spectroscopy for the 1.14 day, detached, double-lined eclipsing binary BT Vul (F0+F7). Our radial-velocity monitoring and light curve analysis lead to absolute masses and radii of M1 = 1.5439 +/- 0.0098 MSun and R1 = 1.536 +/- 0.018 RSun for the primary, and M2 = 1.2196 +/- 0.0080 MSun and R2 = 1.151 +/- 0.029 RSun for the secondary. The effective temperatures are 7270 +/- 150 K and 6260 +/- 180 K, respectively. Both stars are rapid rotators, and the orbit is circular. A comparison with stellar evolution models from the MIST series shows excellent agreement with these determinations, for a composition of [Fe/H] = +0.08 and an age of 350 Myr. The two components of BT Vul are very near the zero-age main sequence.

[11]  arXiv:2004.00023 [pdf, other]

Title: Why do extremely massive disc galaxies exist today?

Authors: Ryan A. Jackson, Garreth Martin, Sugata Kaviraj, Clotilde Laigle, Julien Devriendt, Yohan Dubois, Christophe Pichon

Comments: 8 pages, 4 figure, accepted in MNRAS

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

Galaxy merger histories correlate strongly with stellar mass, largely regardless of morphology. Thus, at fixed stellar mass, spheroids and discs share similar assembly histories, both in terms of the frequency of mergers and the distribution of their mass ratios. Since mergers are the principal drivers of disc-to-spheroid morphological transformation, and the most massive galaxies typically have the richest merger histories, it is surprising that discs exist at all at the highest stellar masses (e.g. beyond the knee of the mass function). Using Horizon-AGN, a cosmological hydro-dynamical simulation, we show that extremely massive (M*> 10^11.4 MSun) discs are created via two channels. In the primary channel (accounting for ~70% of these systems and ~8% of massive galaxies) the most recent, significant merger (stellar mass ratio > 1:10) between a massive spheroid and a gas-rich satellite `spins up' the spheroid by creating a new rotational stellar component, leaving a massive disc as the remnant. In the secondary channel (accounting for ~30% of these systems and ~3% of massive galaxies), a system maintains a disc throughout its lifetime, due to an anomalously quiet merger history. Not unexpectedly, the fraction of massive discs is larger at higher redshift, due to the Universe being more gas-rich. The morphological mix of galaxies at the highest stellar masses is, therefore, a strong function of the gas fraction of the Universe. Finally, these massive discs have similar black-hole masses and accretion rates to massive spheroids, providing a natural explanation for why a minority of powerful AGN are surprisingly found in disc galaxies.

[12]  arXiv:2004.00025 [pdf, other]

Title: Searching for Electromagnetic Counterparts to Gravitational-wave Merger Events with the Prototype Gravitational-wave Optical Transient Observer (GOTO-4)

Authors: B. P. Gompertz, R. Cutter, D. Steeghs, D. K. Galloway, J. Lyman, K. Ulaczyk, M. J. Dyer, K. Ackley, V. S. Dhillon, P. T. O'Brien, G. Ramsay, S. Poshyachinda, R. Kotak, L. Nuttall, R. P. Breton, E. Pallé, D. Pollacco, E. Thrane, S. Aukkaravittayapun, S. Awiphan, M. J. I. Brown, U. Burhanudin, P. Chote, A. A. Chrimes, E. Daw, C. Duffy, R. A. J. Eyles-Ferris, T. Heikkilä, P. Irawati, M. R. Kennedy, T. Killestein, A. J. Levan, S. Littlefair, L. Makrygianni, T. Marsh, D. Mata Sánchez, S. Mattila, J. Maund, J. McCormac, D. Mkrtichian, Y. -L. Mong, J. Mullaney, B. Müller, A. Obradovic, E. Rol, U. Sawangwit, E. R. Stanway, R. L. C. Starling, P. Strøm, S. Tooke, R. West, K. Wiersema

Comments: 12 pages, 7 figures, 3 tables. Submitted to MNRAS

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

We report the results of optical follow-up observations of 29 gravitational-wave triggers during the first half of the LIGO-Virgo Collaboration (LVC) O3 run with the Gravitational-wave Optical Transient Observer (GOTO) in its prototype 4-telescope configuration (GOTO-4). While no viable electromagnetic counterpart candidate was identified, we estimate our 3D (volumetric) coverage using test light curves of on- and off-axis gamma-ray bursts and kilonovae. In cases where the source region was observable immediately, GOTO-4 was able to respond to a GW alert in less than a minute. The average time of first observation was $8.79$ hours after receiving an alert ($9.90$ hours after trigger). A mean of $732.3$ square degrees were tiled per event, representing on average $45.3$ per cent of the LVC probability map, or $70.3$ per cent of the observable probability. This coverage will further improve as the facility scales up alongside the localisation performance of the evolving gravitational-wave detector network. Even in its 4-telescope prototype configuration, GOTO is capable of detecting AT2017gfo-like kilonovae beyond 200 Mpc in favourable observing conditions. We cannot currently place meaningful electromagnetic limits on the population of distant ($\hat{D}_L = 1.3$ Gpc) binary black hole mergers because our test models are too faint to recover at this distance. However, as GOTO is upgraded towards its full 32-telescope, 2 node (La Palma & Australia) configuration, it is expected to be sufficiently sensitive to cover the predicted O4 binary neutron star merger volume, and will be able to respond to both northern and southern triggers.

[13]  arXiv:2004.00031 [pdf, other]

Title: Constraints on the circumburst environments of short gamma-ray bursts

Authors: Brendan O'Connor (GWU), Paz Beniamini (Caltech), Chryssa Kouveliotou (GWU)

Comments: 19 pages, 9 figures, submitted to MNRAS

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

Observational follow-up of well localized short gamma-ray bursts (SGRBs) has left $20-30\%$ of the population without a coincident host galaxy association to deep optical and NIR limits ($\gtrsim 26$ mag). These SGRBs have been classified as observationally hostless due to their lack of strong host associations. It has been argued that these hostless SGRBs could be an indication of the large distances traversed by the binary neutron star system (due to natal kicks) between its formation and its merger (leading to a SGRB). The distances of GRBs from their host galaxies can be indirectly probed by the surrounding circumburst densities. We show that a lower limit on those densities can be obtained from early afterglow lightcurves. We find that $\lesssim16\%$ of short GRBs in our sample took place at densities $\lesssim10^{-4}$ cm$^{-3}$. These densities represent the expected range of values at distances greater than the host galaxy's virial radii. We find that out of the five SGRBs in our sample that have been found to be observationally hostless, none are consistent with having occurred beyond the virial radius of their birth galaxies. This implies one of two scenarios. Either these observationally hostless SGRBs occurred outside of the half-light radius of their host galaxy, but well within the galactic halo, or in host galaxies at moderate to high redshifts ($z\gtrsim 2$) that were missed by follow-up observations.

[14]  arXiv:2004.00036 [pdf, other]

Title: Standard-siren cosmology using gravitational waves from binary black holes

Authors: Zhi-Qiang You, Xing-Jiang Zhu, Gregory Ashton, Eric Thrane, Zong-Hong Zhu

Comments: 9 pages, 9 figures

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

Gravitational-wave astronomy provides a unique new way to study the expansion history of the Universe. In this work, we investigate the impact future gravitational-wave observatories will have on cosmology. Third-generation observatories like the Einstein Telescope and Cosmic Explorer will be sensitive to essentially all of the binary black hole coalescence events in the Universe. Recent work by \cite{farr2019future} points out that features in the stellar-mass black hole population break the mass-redshift degeneracy, facilitating precise determination of the Hubble parameter without electromagnetic counterparts or host galaxy catalogues. Using a hierarchical Bayesian inference model, we show that with one year of observation by the Einstein Telescope, the Hubble constant will be measured to $\lesssim0.5\%$. We show that this method can be used to perform Bayesian model selection between cosmological models. As an illustrative example, we show that a decisive statement can be made comparing the $\Lambda$CDM and RHCT cosmic models using just one week of data from the Einstein Telescope.

[15]  arXiv:2004.00037 [pdf, other]

Title: Giant Planet Influence on the Collective Gravity of a Primordial Scattered Disk

Authors: Alexander Zderic, Ann-Marie Madigan

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

Axisymmetric disks of high eccentricity, low mass bodies on near-Keplerian orbits are unstable to an out-of-plane buckling. This "inclination instability" exponentially grows the orbital inclinations, raises perihelia distances and clusters in argument of perihelion. Here we examine the instability in a massive primordial scattered disk including the orbit-averaged gravitational influence of the giant planets. We show that differential apsidal precession induced by the giant planets will suppress the inclination instability unless the primordial mass is $\gtrsim 20$ Earth masses. We also show that the instability should produce a "perihelion gap" at semi-major axes of hundreds of AU, as the orbits of the remnant population are more likely to have extremely large perihelion distances ($\mathcal{O}(100~\rm{AU})$) than intermediate values.

[16]  arXiv:2004.00043 [pdf, ps, other]

Title: Neutrinos and gravitational waves from magnetized neutrino-dominated accretion discs with magnetic coupling

Authors: Cui-Ying Song, Tong Liu, Yun-Feng Wei

Comments: 10 pages, 7 figures, accepted for publication in MNRAS

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

Gamma-ray bursts (GRBs) might be powered by a black hole (BH) hyperaccretion systems via the Blandford-Znajek (BZ) mechanism or neutrino annihilation from neutrino-dominated accretion flows (NDAFs). Magnetic coupling (MC) between the inner disc and BH can transfer angular momentum and energy from the fast-rotating BH to the disc. The neutrino luminosity and neutrino annihilation luminosity are both efficiently enhanced by the MC process. In this paper, we study the structure, luminosity, MeV neutrinos, and gravitational waves (GWs) of magnetized NDAFs (MNDAFs) under the assumption that both the BZ and MC mechanisms are present. The results indict that the BZ mechanism will compete with the neutrino annihilation luminosity to trigger jets under the different partitions of the two magnetic mechanisms. The typical neutrino luminosity and annihilation luminosity of MNDAFs are definitely higher than those of NDAFs. The typical peak energy of neutrino spectra of MNDAFs is higher than that of NDAFs, but similar to those of core-collapse supernovae. Moreover, if the MC process is dominant, then the GWs originating from the anisotropic neutrino emission will be stronger particularly for discs with high accretion rates.

[17]  arXiv:2004.00051 [pdf, other]

Title: The Ups & Downs of Accreting X-ray Pulsars: Decade-long observations with the Fermi Gamma-ray Burst Monitor

Authors: C. Malacaria, P. Jenke, O.J. Roberts, C.A. Wilson-Hodge, W.H. Cleveland, B. Mailya (on behalf of the GBM Accreting Pulsars Program team)

Comments: Accepted for publication on ApJ

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

We review more than 10 years of continuous monitoring of accreting X-ray pulsars with the all-sky Gamma-ray Burst Monitor (GBM) aboard the Fermi Gamma-ray Space Telescope. Our work includes data from the start of GBM operations in August 2008, through to November 2019. Pulsations from 39 accreting pulsars are observed over an energy range of $10-50\,$keV by GBM. The GBM Accreting Pulsars Program (GAPP) performs data reduction and analysis for each accreting pulsar and makes histories of the pulse frequency and pulsed flux publicly available. We examine in detail the spin histories, outbursts and torque behaviors of the persistent and transient X-ray pulsars observed by GBM. The spin period evolution of each source is analyzed in the context of disk-accretion and quasi-spherical settling accretion driven torque models. Long-term pulse frequency histories are also analyzed over the GBM mission lifetime and compared to those available from the previous BATSE all-sky monitoring mission, revealing previously unnoticed episodes in some of the analyzed sources (such as a torque reversal in 2S 1845-024). We obtain new, or update known, orbital solutions for three sources. Our results demonstrate the capabilities of GBM as an excellent instrument for monitoring accreting X-ray pulsars and its important scientific contribution to this field.

[18]  arXiv:2004.00065 [pdf, other]

Title: A photochemical model of ultraviolet atomic line emissions in the inner coma of comet 67P/Churyumov-Gerasimenko

Authors: Susarla Raghuram, Anil Bhardwaj

Comments: 15 pages, 10 figures

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

Alice ultraviolet spectrometer onboard Rosetta space mission observed several spectroscopic emissions emanated from volatile species of comet 67P/Churyumov-Gerasimenko (hear after 67P/C-G) during its entire escorting phase. We have developed a photochemical model for comet 67P/C-G to study the atomic hydrogen (HI 1216, 1025, & 973 Ang), oxygen (OI 1152, 1304, & 1356 Ang), and carbon (CI 1561 & 1657 Ang) line emissions by accounting for major production pathways. The developed model has been used to calculate the emission intensities of these lines as a function of nucleocentric projected distance and also along with the nadir view by varying the input parameters, viz., neutral abundances and cross sections. We have quantified the percentage contributions of photon and electron impact dissociative excitation processes to the total intensity of the emission lines, which has important relevance for the analysis of Alice observed spectra. It is found that in comet 67P/C-G, which is having a neutral gas production rate of about 10$^{27}$ s$^{-1}$ when it was at 1.56 AU from the Sun, photodissociative excitation processes are more significant compared to electron impact reactions in determining the atomic emission intensities. Based on our model calculations, we suggest that the observed atomic hydrogen, oxygen, and carbon emission intensities can be used to derive H$_2$O, O$_2$, and CO, abundances, respectively, rather than electron density in the coma of 67P/C-G, when the comet has a gas production rate of $\ge$ 10$^{27}$ s$^{-1}$.

[19]  arXiv:2004.00066 [pdf, ps, other]

Title: The Rich Lack Close Neighbours: The Dependence of Blue-Straggler Fraction on Metallicity

Authors: Rosemary F. G. Wyse (Johns Hopkins and KITP), Maxwell Moe (Steward Observatory), Kaitlin M. Kratter (Steward Observatory)

Comments: 11 pages, 3 figures, MNRAS in press (March 2020

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

Blue straggler stars (BSS) have been identified in star clusters and in field populations in our own Milky Way galaxy and in its satellite galaxies. They manifest as stars bluer and more luminous than the dominant old population, and usually have a spatial distribution that follows the old population. Their progenitors are likely to have been close binaries. We investigate trends of the BSS population in dwarf spheroidal galaxies (dSph) and in the bulge of the Milky Way and find an anti-correlation between the relative frequency of BSS and the metallicity of the parent population. The rate of occurrence of BSS in the metal-poor dwarf galaxies is approximately twice that found in the solar-metallicity bulge population. This trend of decreasing relative population of BSS with increasing metallicity mirrors that found for the close-binary fraction in the field population of the Milky Way. We argue that the dominant mode of BSS formation in low-density environments is likely to be mass transfer in close-binary systems. It then follows that the similarity between the trends for BSS in the dSph and field stars in our Galaxy supports the proposal that the small-scale fragmentation during star formation is driven by the same dominant physical process, despite the diversity in environments, plausibly gravitational instability of proto-stellar discs.

[20]  arXiv:2004.00072 [pdf, other]

Title: Jupiter's Equatorial Plumes and Hot Spots: Spectral Mapping from Gemini/TEXES and Juno/MWR

Authors: L.N. Fletcher, G.S. Orton, T.K. Greathouse, J.H. Rogers, Z. Zhang, F.A. Oyafuso, G. Eichstädt, H. Melin, C. Li, S.M. Levin, S. Bolton, M. Janssen, H-J. Mettig, D. Grassi, A. Mura, A. Adriani

Comments: 50 pages, 16 figures, accepted for publication in JGR-Planets

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

We present multi-wavelength measurements of the thermal, chemical, and cloud contrasts associated with the visibly dark formations (also known as 5-$\mu$m hot spots) and intervening bright plumes on the boundary between Jupiter's Equatorial Zone (EZ) and North Equatorial Belt (NEB). Observations made by the TEXES 5-20 $\mu$m spectrometer at the Gemini North Telescope in March 2017 reveal the upper-tropospheric properties of 12 hot spots, which are directly compared to measurements by Juno using the Microwave Radiometer (MWR), JIRAM at 5 $\mu$m, and JunoCam visible images. MWR and thermal-infrared spectroscopic results are consistent near 0.7 bar. Mid-infrared-derived aerosol opacity is consistent with that inferred from visible-albedo and 5-$\mu$m opacity maps. Aerosol contrasts, the defining characteristics of the cloudy plumes and aerosol-depleted hot spots, are not a good proxy for microwave brightness. The hot spots are neither uniformly warmer nor ammonia-depleted compared to their surroundings at $p<1$ bar. At 0.7 bar, the microwave brightness at the edges of hot spots is comparable to other features within the NEB. Conversely, hot spots are brighter at 1.5 bar, signifying either warm temperatures and/or depleted NH$_3$ at depth. Temperatures and ammonia are spatially variable within the hot spots, so the precise location of the observations matters to their interpretation. Reflective plumes sometimes have enhanced NH$_3$, cold temperatures, and elevated aerosol opacity, but each plume appears different. Neither plumes nor hot spots had microwave signatures in channels sensing $p>10$ bars, suggesting that the hot-spot/plume wave is a relatively shallow feature.

[21]  arXiv:2004.00098 [pdf, other]

Title: The case for the fundamental $M_{\rm BH}$-$σ$ relation

Authors: Christopher Marsden (1), Francesco Shankar (1), Michele Ginolfi (2), Kastytis Zubovas (3) ((1) University of Southampton, UK, (2) Observatoire de Genève, Switzerland, (3) Center for Physical Sciences and Technology, Lithuania)

Comments: 22 pages, 5 figures. Frontiers in Physics, accepted

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

Strong scaling relations between host galaxy properties (such as stellar mass, bulge mass, luminosity, effective radius etc) and their nuclear supermassive black hole's mass point towards a close co-evolution. In this work, we first review previous efforts supporting the fundamental importance of the relation between supermassive black hole mass and stellar velocity dispersion ($M_{\rm BH}$-$\sigma_{\rm e}$). We then present further original work supporting this claim via analysis of residuals and principal component analysis applied to some among the latest compilations of local galaxy samples with dynamically measured supermassive black hole masses. We conclude with a review of the main physical scenarios in favour of the existence of a $M_{\rm BH}$-$\sigma_{\rm e}$ relation, with a focus on momentum-driven outflows.

[22]  arXiv:2004.00102 [pdf, other]

Title: Axisymmetric Radiative Transfer Models of Kilonovae

Authors: Oleg Korobkin (1 and 2), Ryan Wollaeger (1), Christopher Fryer (1 and 2), Aimee L. Hungerford (1 and 2), Stephan Rosswog (3), Christopher Fontes (1), Matthew Mumpower (1 and 2), Eve Chase (4), Wesley Even (1 and 2), Jonah M. Miller (1), G. Wendell Misch (1 and 2), Jonas Lippuner (1 and 2) ((1) LANL CTA, (2) JINA, (3) Stockholm University, (4) CIERA, Northwestern University)

Comments: 21 pages, 17 figures: submitted to ApJ

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

The detailed observations of GW170817 proved for the first time directly that neutron star mergers are a major production site of heavy elements. The observations could be fit by a number of simulations that qualitatively agree, but can quantitatively differ (e.g. in total r-process mass) by an order of magnitude. We categorize kilonova ejecta into several typical morphologies motivated by numerical simulations, and apply a radiative transfer Monte Carlo code to study how the geometric distribution of the ejecta shapes the emitted radiation. We find major impacts on both spectra and light curves. The peak bolometric luminosity can vary by two orders of magnitude and the timing of its peak by a factor of five. These findings provide the crucial implication that the ejecta masses inferred from observations are uncertain by at least an order of magnitude. Mixed two-component models with lanthanide-rich ejecta are particularly sensitive to geometric distribution. A subset of mixed models shows very strong viewing angle dependence due to lanthanide "curtaining", which persists even if the relative mass of lanthanide-rich component is small. The angular dependence is weak in the rest of our models, but different geometric combinations of the two components lead to a highly diverse set of light curves. We identify geometry-dependent P Cygni features in late spectra that directly map out strong lines in the simulated opacity of neodymium, which can help to constrain the ejecta geometry and to directly probe the r-process abundances.

[23]  arXiv:2004.00114 [pdf, other]

Title: Clustering of Local Group distances: publication bias or correlated measurements? VII. A distance framework out to 100 Mpc

Authors: Richard de Grijs, Giuseppe Bono

Comments: 15 pages, 3 figures; accepted for publication in ApJS

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

We consider the published distance moduli to the Fornax and Coma galaxy clusters, with emphasis on the period since 1990. We have carefully homogenized our catalogs of distance moduli onto the distance scale established in the previous papers in this series. We assessed systematic differences associated with the use of specific tracers, and discarded results based on application of the Tully--Fisher relation and of globular cluster and planetary nebula luminosity functions. We recommend `best' weighted relative distance moduli for the Fornax and Coma clusters with respect to the Virgo cluster of $\Delta (m-M)_0^{\rm Fornax - Virgo} = 0.18 \pm 0.28 $ mag and $\Delta (m-M)_0^{\rm Coma - Virgo} = 3.75 \pm 0.23$ mag. The set of weighted mean distance moduli (distances) we derived as most representative of the clusters' distances is, \begin{eqnarray} (m-M)_0^{\rm Fornax} &=& 31.41 \pm 0.15 \mbox{ mag } (D = 19.1^{+1.4}_{-1.2} \mbox{ Mpc) and} \nonumber
&=& 31.21 \pm 0.28 \mbox{ mag } (D = 17.5^{+2.4}_{-2.2} \mbox{ Mpc)}; \nonumber \\ (m-M)_0^{\rm Coma} &=& 34.99 \pm 0.38 \mbox{ mag } (D = 99.5^{+19.0}_{-15.9} \mbox{ Mpc) and} \nonumber
&=& 34.78 \pm 0.27 \mbox{ mag } (D = 90.4^{+11.9}_{-10.6} \mbox{ Mpc)}, \nonumber \end{eqnarray} where the first value for each cluster is the result of our analysis of the direct distance moduli, while the second modulus is based on distance moduli relative to the Virgo cluster. The absolute and relative distance moduli for both clusters are mutually consistent within the uncertainties; the relative distance moduli yield shorter distances by $\sim$1$\sigma$. Lingering uncertainties in the underlying absolute distance scale appear to have given rise to a systematic uncertainty on the order of 0.20 mag.

[24]  arXiv:2004.00122 [pdf, other]

Title: Radio, EUV, and X-Ray Observations During a Filament Rise in the 2011 June 7 Solar Flare

Authors: Marian Karlicky, Jana Kasparova, Robert Sych

Comments: 11 pages, 11 figures

Journal-ref: The Astrophysical Journal,888:18(9pp), 2020 January 1

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

The most energetic flares start with a filament rise followed by magnetic reconnection below this filament. The start of the reconnection corresponds to the beginning of the flare impulsive phase. In this paper we study processes before this phase. During the filament rise we recognize an unusual radio continuum with a starting boundary drifting toward lower frequencies. The estimated velocity of the agent generating this continuum boundary is about 400 km/s, similar to that of the rising filament. In association with this filament rise, transient X-ray sources and extreme ultaviolet (EUV) brightenings are found near the filament footpoint and outside the locations where later two parallel flare ribbons appear. Moreover, oscillations with a ~30 s period are found simultaneously in radio, EUV, and X-ray observations. Around the end of these oscillations the flare impulsive phase starts as seen in observations of the drifting pulsation structure and X-ray source located at the upper part of the rising filament. We interpret the unusual radio continuum and transient X-ray sources, which are located outside the two parallel flare ribbons, as those generated during an interaction of the rising filament with the above-lying magnetic loops. The EUV brightening at the filament footpoint could be a signature of the magnetic reconnection inside the magnetic rope carrying the filament. Possible scenarios of the ~30 s period oscillations in radio, X-ray, and EUV are discussed.

[25]  arXiv:2004.00126 [pdf, other]

Title: Gravitoviscous protoplanetary disks with a dust component. III. Evolution of gas, dust, and pebbles

Authors: Vardan G. Elbakyan, Anders Johansen, Michiel Lambrechts, Vitaly Akimkin, Eduard I. Vorobyov

Comments: 13 pages, 10 figures

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

We study the dynamics and growth of dust particles in circumstellar disks of different masses that are prone to gravitational instability during the critical first Myr of their evolution. The dust component is made up of two different components: micron-sized dust and grown dust of evolving size. For the dust component, we considered the dust coagulation, fragmentation, momentum exchange with the gas, and dust self-gravity. We found that the micron-sized dust particles grow rapidly in the circumstellar disk, reaching a few cm in size in the inner 100 au of the disk during less than 100 kyr after the disk formation, provided that fragmentation velocity is $30\rm~ms^{-1}$. Due to the accretion of micron dust particles from the surrounding envelope, which serves as a micron dust reservoir, the approximately cm-sized dust particles continue to be present in the disk for more than 900 kyr after the disk formation and maintain a dust-to-gas ratio close to 0.01. We show that a strong correlation exists between the gas and pebble fluxes in the disk. We find that radial surface density distribution of pebbles in the disk shows power-law distribution with an index similar to that of the Minimum-mass solar nebula (MMSN) regardless the disk mass. We also show that the gas surface density in our models agrees well with measurements of dust in protoplanetary disks of AS 209, HD 163296, and DoAr 25 systems. Pebbles are formed during the very early stages of protoplanetary disk evolution. They play a crucial role in the planet formation process. Our disc simulations reveal the early onset ($<10^5$ yr) of an inwards-drifting flux of pebble-sized particles that makes up approximately between one hundredth and one tenth of the gas mass flux, which appears consistent with mm-observations of discs. (Abridged)

[26]  arXiv:2004.00146 [pdf, other]

Title: Tidal Disruptions of White Dwarfs: Theoretical Models and Observational Prospects

Authors: Kate Maguire, Michael Eracleous, Peter G. Jonker, Morgan MacLeod, Stephan Rosswog

Comments: Accepted for publication in Springer Space Science Reviews. Chapter in review, 'The Tidal Disruption of Stars by Massive Black Holes', editors: P. G. Jonker, S. Phinney, E. M. Rossi, S. v. Velzen, I. Arcavi & M. Falanga

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

White dwarf stars that enter the tidal radius of black holes with masses $\lesssim$ $10^5$ M$_{\odot}$ are doomed to be ripped apart by tidal forces. Black holes in this mass range between stellar black holes and supermassive black holes have not been conclusively identified so the detection of a tidal disruption of a white dwarf would provide clear evidence for the existence of intermediate-mass black holes. In this review, we present a theoretical and observational overview of the transient events that result from the tidal disruptions of white dwarfs by intermediate-mass black holes. This includes discussion of the latest simulations and predicted properties, the results of observational searches, as well as a summary of the potential for gravitational wave emission to be detected with upcoming missions.

[27]  arXiv:2004.00158 [pdf, other]

Title: Outside the Lyman-break box: detecting Lyman continuum emitters at $3.5<z<5.1$ with CLAUDS

Authors: Uroš Meštrić, E. V. Ryan-Weber, J. Cooke, R. Bassett, M. Sawicki, A. L. Faisst, K. Kakiichi, A. K. Inoue, M. Rafelski, L. J. Prichard, S. Arnouts, T. Moutard, J. Coupon, A. Golob, S. Gwyn

Comments: 22 pages, 12 figures, accepted for publication 30/3/2020

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

Identifying non-contaminated sample of high-redshift galaxies with escaping Lyman continuum (LyC) flux is important for understanding the sources and evolution of cosmic reionization. We present CLAUDS $u$-band photometry of the COSMOS field to probe LyC radiation from spectroscopically confirmed galaxies at $z\geq3.5$ and outside the standard Lyman-break galaxy colour selection expectations. Complementary to the CLAUDS data, we use Subaru multi-filter photometry, \textit {Hubble Space Telescope} ($HST$) multi-filter imaging, and the spectroscopic surveys D10K, VUDS and 3D-HST. We present a sample of Lyman continuum galaxy (LCG) candidates in the redshift range $3.5\lesssim z\lesssim5.1$. Here, we introduce 5 LCG candidates, where two are flagged quality 1 and three quality 2. The estimated $f_{\rm esc}^{\rm abs}$ for quality 1 candidates are in the range $\sim5\% - 73\%$ and $\sim30\% - 93\%$. These estimates are based on our derived parameters from individual galaxies as inputs to a range of BPASS models as well as mean intergalactic medium (IGM) and maximal intergalactic and circumgalactic media (IGM+CGM) transmission. We conclude that our search for LCGs is most likely biased to lines of sight with low HI densities or free from Lyman limit systems. Our two best LCG candidates have EW (Ly$\alpha)\leq50$\AA\ and we find no correlation or anti-correlation between EW (Ly$\alpha$), $f_{\rm esc}^{\rm abs}$, and $R_{\rm obs}$, the ratio of ionizing to non-ionizing observed flux in the measured passbands. Stacking candidates without solid LyC detections ($S/N<3$) results in an estimated $f_{\rm esc}^{\rm abs}$ from galaxies not greater than $1\%$.

[28]  arXiv:2004.00164 [pdf, ps, other]

Title: The GBT 350-MHz Drift Scan Pulsar Survey. III. Detection of a magnetic field in the eclipsing material of PSR J2256-1024

Authors: Kathryn Crowter, Ingrid H. Stairs, Christee A. McPhee, Anne M. Archibald, Jason Boyles, Jason Hessels, Chen Karako-Argaman, Duncan R. Lorimer, Ryan S. Lynch, Maura A. McLaughlin, Scott M. Ransom, Mallory S. E. Roberts, Kevin Stovall, Joeri van Leeuwen

Comments: 14 pages, 8 figures

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

We present the first measurement of a non-zero magnetic field in the eclipsing material of a black widow pulsar. Black widows are millisecond pulsars which are ablating their companions; therefore they are often proposed as one potential source of isolated millisecond pulsars. PSR J2256-1024 is an eclipsing black widow discovered at radio wavelengths and later also observed in the X-ray and gamma parts of the spectrum. Here we present the radio timing solution for PSR J2256-1024, polarization profiles at 350, 820, and 1500~MHz and an investigation of changes in the polarization profile due to eclipsing material in the system. In the latter we find evidence of Faraday rotation in the linear polarization shortly after eclipse, measuring a rotation measure of 0.44(6) rad per meter squared and a corresponding line-of-sight magnetic field of 3.5(17) mG.

[29]  arXiv:2004.00168 [pdf, other]

Title: Long-term statistics of pulsar glitches triggered by a Brownian stress accumulation process

Authors: Julian B. Carlin, Andrew Melatos

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

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

A microphysics-agnostic meta-model of rotational glitches in rotation-powered pulsars is developed, wherein the globally averaged internal stress accumulates as a Brownian process between glitches, and a glitch is triggered once a critical threshold is surmounted. Precise, falsifiable predictions are made regarding long-term event statistics in individual pulsars. For example, the Spearman cross-correlation coefficient between the size of a glitch and the waiting time until the next glitch should exceed 0.25 in all pulsars. Among the six pulsars with the most recorded glitches, PSR J0537$-$6910 and PSR J0835$-$4510 are consistent with the predictions of the meta-model, while PSR J1740$-$3015 and PSR J0631$+$1036 are not. PSR J0534$+$2200 and PSR J1341$-$6220 are only consistent with the meta-model, if there exists an undetected population of small glitches with small waiting times, which we do not resolve. The results are compared with a state-dependent Poisson process, another microphysics-agnostic meta-model in the literature. The results are also applied briefly to recent pulse-to-pulse observations of PSRJ0835$-$4510, which appear to reveal evidence for a negative fluctuation in rotation frequency just prior to the 2016 glitch.

[30]  arXiv:2004.00170 [pdf, ps, other]

Title: Weak lensing clusters from HSC survey first-year data: Mitigating the dilution effect of foreground and cluster member galaxies

Authors: Takashi Hamana, Masato Shirasaki, Yen-Ting Lin

Comments: 30 pages, 12 figures, submitted to PASJ, comments welcome. A version with full resolution figures and additional information about weak lensing peaks are available from this http URL

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

We present weak lensing cluster search using Hyper Suprime-Cam Subaru Strategic Program (HSC survey) first-year data. We pay a special attention to the dilution effect of cluster member and foreground galaxies on weak lensing peak signal-to-noise ratios ($SN$s); we adopt the globally normalized weak lensing estimator which is least affected by cluster member galaxies, and we select source galaxies by using photometric redshift information to mitigate the effect of foreground galaxies. We produce six samples of source galaxies with different low-$z$ galaxy cuts, construct weak lensing mass maps for each of source sample, and search for high peaks in the mass maps that cover the effective survey area of $\sim$120 deg$^2$. We compile six catalogs of high peaks into the sample of cluster candidates which contains 124 high peaks with $SN\ge 5$. We cross-match the peak sample with the public optical cluster catalog constructed from the same HSC survey data to identify cluster counterparts of the peaks. We find that 107 out of 124 peaks have matched clusters within 5 arcmin from peak positions. Among them, we define a sub-sample of 64 secure clusters that we use to examine dilution effects on our weak lensing peak finding. We find that source samples with the low-$z$ galaxy cuts mitigate the dilution effect on peak $SN$s of high-$z$ clusters ($z > 0.3$), and thus combining multiple peak catalogs from different source samples improves the efficiency of weak lensing cluster searches.

[31]  arXiv:2004.00203 [pdf, ps, other]

Title: Bondi on spherically symmetric accretion

Authors: Philip J. Armitage

Comments: Part of a series, marking the Royal Astronomical Society's bicentennial, revisiting influential papers published by the Society

Journal-ref: Astronomy & Geophysics, Volume 61, 2.40-2.42 (2020)

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

Hermann Bondi's 1952 paper "On spherically symmetrical accretion" is recognized as one of the foundations of accretion theory. Although Bondi later remarked that it was "not much more than an examination exercise", his mathematical analysis of spherical accretion on to a point mass has found broad use across fields of astrophysics that were embryonic or non-existent at the time of the paper's publication. In this non-technical review, I describe the motivations for Bondi's work, and briefly discuss some of the applications of Bondi accretion in high energy astrophysics, galaxy formation, and star formation.

[32]  arXiv:2004.00208 [pdf, other]

Title: Revisiting the Sun's Strong Differential Rotation along Radial Lines

Authors: Loren I. Matilsky, Bradley W. Hindman, Juri Toomre

Comments: 12 pages, 13 figures, submitted to ApJ

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

Current state-of-the-art models of the solar convection zone consist of solutions to the Navier-Stokes equations in rotating, 3D spherical shells. Such models are highly sensitive to the choice of boundary conditions. Here we present two suites of simulations differing only in their outer thermal boundary condition, which is either one of fixed-entropy or fixed-entropy-gradient. We find that the resulting differential rotation is markedly different between the two sets. The fixed-entropy-gradient simulations have strong differential rotation contrast and isocontours tilted along radial lines (in good agreement with the Sun's interior rotation revealed by helioseismology), while the fixed-entropy simulations have weaker contrast and contours tilted in the opposite sense. We examine in detail the force balances leading to the different rotation profiles and find that the poleward transport of heat by Busse columns plays a key role. We conclude that the Sun's strong differential rotation along radial lines may result from the solar emissivity being invariant with latitude (which is similar to the fixed-entropy-gradient condition in our models) and the poleward transport of heat by Busse columns. In future work on convection in the solar context, we strongly advise modelers to use a fixed-gradient outer boundary condition.

[33]  arXiv:2004.00210 [pdf, other]

Title: Estimation of losses in a 300 m filter cavity and quantum noise reduction in the KAGRA gravitational-wave detector

Authors: Eleonora Capocasa, Matteo Barsuglia, Jérôme Degallaix, Laurent Pinard, Nicolas Straniero, Roman Schnabel, Kentaro Somiya, Yoichi Aso, Daisuke Tatsumi, Raffaele Flaminio

Journal-ref: Phys. Rev. D 93, 082004 (2016)

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

The sensitivity of the gravitational-wave detector KAGRA, presently under construction, will be limited by quantum noise in a large fraction of its spectrum. The most promising technique to increase the detector sensitivity is the injection of squeezed states of light, where the squeezing angle is dynamically rotated by a Fabry-P\'erot filter cavity. One of the main issues in the filter cavity design and realization is the optical losses due to the mirror surface imperfections. In this work we present a study of the specifications for the mirrors to be used in a 300 m filter cavity for the KAGRA detector. A prototype of the cavity will be constructed at the National Astronomical Observatory of Japan, inside the infrastructure of the former TAMA interferometer. We also discuss the potential improvement of the KAGRA sensitivity, based on a model of various realistic sources of losses and their influence on the squeezing amplitude.

[34]  arXiv:2004.00229 [pdf]

Title: The effect of high nitrogen pressures on the habitable zone and an appraisal of greenhouse states

Authors: Ramses M. Ramirez

Comments: Published in The Monthly Notices of the Royal Astronomical Society (27 pages, 7 figures)

Journal-ref: Monthly Notices of the Royal Astronomical Society, 494, 1, 259 to 270 (2020)

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

The habitable zone is the main tool that mission architectures utilize to select potentially habitable planets for follow up spectroscopic observation. Given its importance, the precise size and location of the habitable zone remains a hot topic, as many studies, using a hierarchy of models, have assessed various factors including: atmospheric composition, time, and planetary mass. However, little work has assessed how the habitable zone changes with variations in background nitrogen pressure, which is directly connected to the habitability and life bearing potential of planets. Here, I use an advanced energy balance model with clouds to show that our solar system habitable zone is about 0.9 to 1.7 AU, assuming a 5 bar nitrogen background pressure and a maximum 100 percent cloud cover at the inner edge. This width is about 20 percent wider than the conservative habitable zone estimate. Similar extensions are calculated for A to M stars. I also show that cooling clouds and hazes and high background pressures can decrease the runaway greenhouse threshold temperature to approximately 300 K (or less) for planets orbiting any star type. This is because the associated increase in planetary albedo enables stable climates closer to the star, where rapid destabilization can be triggered from a lower mean surface temperature. Enhanced longwave emission for planets with very high stratospheric temperatures also permits stable climates at smaller orbital distances. The model predicts a runaway greenhouse above approximately 330 K for planets orbiting the Sun, which is consistent with previous work. However, moist greenhouses only occur for planets orbiting A-stars.

[35]  arXiv:2004.00242 [pdf, other]

Title: Cassini states of a rigid body with a liquid core

Authors: Gwenaël Boué

Comments: 25 pages, 3 figures. To be published in Celestial Mechanics and Dynamical Astronomy

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

The purpose of this work is to determine the location and stability of the Cassini states of a celestial body with an inviscid fluid core surrounded by a perfectly rigid mantle. Both situations where the rotation speed is either non-resonant or trapped in a p:1 spin-orbit resonance where p is a half integer are addressed. The rotation dynamics is described by the Poincar\'e-Hough model which assumes a simple motion of the core. The problem is written in a non-canonical Hamiltonian formalism. The secular evolution is obtained without any truncation in obliquity, eccentricity nor inclination. The condition for the body to be in a Cassini state is written as a set of two equations whose unknowns are the mantle obliquity and the tilt angle of the core spin-axis. Solving the system with Mercury's physical and orbital parameters leads to a maximum of 16 different equilibrium configurations, half of them being spectrally stable. In most of these solutions the core is highly tilted with respect to the mantle. The model is also applied to Io and the Moon.

[36]  arXiv:2004.00254 [pdf, other]

Title: Analyses of residual accelerations for TianQin based on the global MHD simulation

Authors: Wei Su, Yan Wang, Ze-Bing Zhou, Yan-Zheng Bai, Yang Guo, Chen Zhou, Tom Lee, Ming Wang, Ming-Yue Zhou, Tong Shi, Hang Yin, Bu-Tian Zhang

Comments: 20 pages, 8 figures

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

TianQin is a proposed space-based gravitational wave observatory. It is designed to detect the gravitational wave signals in the frequency range of 0.1 mHz -- 1 Hz. At a geocentric distance of $10^5$ km, the plasma in the earth magnetosphere will contribute as the main source of environmental noises. Here, we analyze the acceleration noises that are caused by the magnetic field of space plasma for the test mass of TianQin. The real solar wind data observed by the Advanced Composition Explorer are taken as the input of the magnetohydrodynamic simulation. The Space Weather Modeling Framework is used to simulate the global magnetosphere of the earth, from which we obtain the plasma and magnetic field parameters on the detector's orbits. We calculate the time series of the residual accelerations and the corresponding amplitude spectral densities on these orbit configurations. We find that the residual acceleration produced by the interaction between the TM's magnetic moment induced by the space magnetic field and the spacecraft magnetic field ($\bm{a}_{\rm M1}$) is the dominant term, which can approach $10^{-15}$ m/s$^2$/Hz$^{1/2}$ at $f\lesssim 0.2$ mHz for the nominal values of the magnetic susceptibility ($\chi_{\rm m} = 10^{-5}$) and the magnetic shielding factor ($\xi_{\rm m} = 10$) of the test mass. The ratios between the amplitude spectral density of the acceleration noise caused by the space magnetic field and the preliminary goal of the inertial sensor are 0.34 and 0.07 at 1 mHz and 10 mHz, respectively. We discuss the further reduction of this acceleration noise by decreasing $\chi_{\rm m}$ and/or increasing $\xi_{\rm m}$ in the future instrumentation development for TianQin.

[37]  arXiv:2004.00257 [pdf, other]

Title: Concat Convolutional Neural Network for Pulsar Candidate Selection

Authors: Qingguo Zeng, Xiangru Li, Haitao Lin

Comments: 10 pages, 8figures

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

Pulsar searching is essential for the scientific research in the field of physics and astrophysics. As the development of the radio telescope, the exploding volume and it growth speed of candidates growth have brought about several challenges. Therefore, there is an urgent demand for developing an automatic, accurate and efficient pulsar candidate selection method. To meet this need, this work designed a Concat Convolutional Neural Network (CCNN) to identify the candidates collected from the Five-hundred-meter Aperture Spherical Telescope (FAST) data. The CCNN extracts some "pulsar-like" patterns from the diagnostic subplots using Convolutional Neural Network (CNN) and combines these CNN features by a concatenate layer. Therefore, the CCNN is an end-to-end learning model without any need for any intermediate labels, which makes CCNN suitable for the online learning pipeline of pulsar candidate selection. Experimental results on FAST data show that the CCNN outperforms the available state-of-the-art models in similar scenario. It only misses 4 real pulsars out of 326 totally.

[38]  arXiv:2004.00322 [pdf, other]

Title: Iron Line from Neutron Star Accretion Disks in Scalar Tensor Theories

Authors: N. Bucciantini (INAF-Arcetri), J. Soldateschi (Univ. Firenze)

Comments: 5 pages, 4 figures, accepted for publication in MNRAS

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

The Fe K_\alpha fluorescent line at 6.4 keV is a powerful probe of the space-time metric in the vicinity of accreting compact objects. We investigated here how some alternative theories of gravity, namely Scalar tensor Theories, that invoke the presence of a non-minimally coupled scalar field and predict the existence of strongly scalarized neutron stars, change the expected line shape with respect to General Relativity. By taking into account both deviations from the general relativistic orbital dynamics of the accreting disk, where the Fe line originates, and the changes in the light propagation around the neutron star, we computed line shapes for various inclinations of the disk with respect to the observer. We found that both the intensity of the low energy tails and the position of the high energy edge of the line change. Moreover we verified that even if those changes are in general of the order of a few percent, they are potentially observable with the next generation of X-ray satellites.

[39]  arXiv:2004.00339 [pdf, other]

Title: Lorentzian Quintessential Inflation

Authors: David Benisty, Eduardo I. Guendelman

Comments: 5 pages

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

From the assumption that the slow roll parameter $\epsilon$ has a Lorentzian form as a function of the e-folds number $N$, a successful model of a quintessential inflation is obtained. The form corresponds to the vacuum energy both in the inflationary and in the dark energy epochs. The form satisfies the condition to climb from small values of $\epsilon$ to $1$ at the end of the inflationary epoch. At the late universe $\epsilon$ becomes small again and this leads to the Dark Energy epoch. The observables that the models predicts fits with the latest Planck data: $r \sim 10^{-3}, n_s \approx 0.965$. Naturally a large dimensionless factor that exponentially amplifies the inflationary scale and exponentially suppresses the dark energy scale appears, producing a sort of {\it{cosmological see saw mechanism}}. We find the corresponding scalar Quintessential Inflationary potential with two flat regions - one inflationary and one as a dark energy with slow roll behavior.

[40]  arXiv:2004.00346 [pdf, other]

Title: Methods for detection and analysis of weak radio sources with single-dish radio telescopes

Authors: M. Marongiu, A. Pellizzoni, E. Egron, T. Laskar, M. Giroletti, S. Loru, A. Melis, G. Carboni, C. Guidorzi, S. Kobayashi, N. Jordana-Mitjans, A. Rossi, C. G. Mundell, R. Concu, R. Martone, L. Nicastro

Comments: 22 pages, 11 figures, 3 tables, pre-print of an article accepted for publication in Experimental Astronomy

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

The detection of faint radio sources (mJy/sub-mJy events) is an open issue in single-dish astronomy. To date, observations of undetected radio sources in single-dish mode often result in a rough upper limit based on the root mean square (RMS) of the image.
Using the Sardinia Radio Telescope (SRT), we compare the sensitivity and robustness of three methods applied to the detection of faint radio sources from raster maps around a known source position: the smart "quick-look" method, the "source extraction" method (typical of high-energy astronomy), and the fit with a 2-D Gaussian. The targets of interest are the faint radio afterglow emission (due to synchrotron radiation) from gamma-ray bursts (GRBs), flashes of high-energy radiation of cosmological origin. To this aim, we developed a Python code specific for the analysis of point-like radio sources applied to the SRT C-band (6.9 GHz) observations of both undetected sources (GRB afterglows of 181201A and 190114C) and the detected Galactic X-ray binary GRS1915+105.
Our comparative analysis of the different detection methods made extensive use of simulations as a useful complement to actual radio observations. The best method for the SRT data analysis is the fit with a 2-D Gaussian, as it pushes down the sensitivity limits of single-dish observations -- with respect to more traditional techniques -- to ~ 1.8 mJy, improving by ~ 40 % compared with the initial value. This analysis shows that -- especially for faint sources -- an accurate knowledge of the radio background is essential.

[41]  arXiv:2004.00355 [pdf, other]

Title: Evidence for a Coronal Shock Wave Origin for Relativistic Protons Producing Solar Gamma-Rays and Observed by Neutron Monitors at Earth

Authors: Athanasios Kouloumvakos, Alexis P. Rouillard, Gerald H. Share, Illya Plotnikov, Ronald Murphy, Athanasios Papaioannou, Yihong Wu

Comments: Accepted for publication in APJ, 18 pages, 12 figures

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

We study the solar eruptive event on 2017 September 10 that produced long-lasting $>$100 MeV $\gamma$-ray emission and a ground level enhancement (GLE72). The origin of the high-energy ions producing late-phase gamma-ray emission (LPGRE) is still an open question, but a possible explanation is proton acceleration at coronal shocks produced by coronal mass ejections. We examine a common shock acceleration origin for both the LPGRE and GLE72. The $\gamma$-ray emission observed by the Fermi-Large Area Telescope exhibits a weak impulsive phase, consistent with that observed in hard X-and $\gamma$-ray line flare emissions, and what appear to be two distinct stages of LPGRE. From a detailed modeling of the shock wave, we derive the 3D distribution and temporal evolution of the shock parameters, and we examine the shock wave magnetic connection with the visible solar disk. The evolution of shock parameters on field lines returning to the visible disk, mirrors the two stages of LPGRE. We find good agreement between the time history of $>$100 MeV $\gamma$-rays and one produced by a basic shock acceleration model. The time history of shock parameters magnetically mapped to Earth agrees with the rates observed by the Fort Smith neutron monitor during the first hour of the GLE72 if we include a 30% contribution of flare-accelerated protons during the first 10 minutes, having a release time following the time history of nuclear $\gamma$-rays. Our analysis provides compelling evidence for a common shock origin for protons producing the LPGRE and most of the particles observed in GLE72.

[42]  arXiv:2004.00400 [pdf, other]

Title: A radiative transfer model for the spiral galaxy M33

Authors: Jordan J. Thirlwall, Cristina C. Popescu, Richard J. Tuffs, Giovanni Natale, Mark Norris, Mark Rushton, Meiert Grootes, Ben Carroll

Comments: 35 pages, 17 figures

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

We present the first radiative transfer (RT) model of a non-edge-on disk galaxy in which the large-scale geometry of stars and dust is self-consistently derived through fitting of multiwavelength imaging observations from the UV to the submm. To this end we used the axi-symmetric RT model of Popescu et al. and a new methodology for deriving geometrical parameters, and applied this to decode the{spectral energy distribution (SED) of M33. We successfully account for both the spatial and spectral energy distribution, with residuals typically within $7\%$ in the profiles of surface brightness and within $8\%$ in the spatially-integrated SED. We predict well the energy balance between absorption and re-emission by dust, with no need to invoke modified grain properties, and we find no submm emission that is in excess of our model predictions. We calculate that $80\pm8\%$ of the dust heating is powered by the young stellar populations. We identify several morphological components in M33, a nuclear, an inner, a main and an outer disc, showing a monotonic trend in decreasing star-formation surface-density ($\Sigma_{\rm SFR}$) from the nuclear to the outer disc. In relation to surface density of stellar mass, the $\Sigma_{\rm SFR}$ of these components define a steeper relation than the "main sequence" of star-forming galaxies, which we call a "structurally resolved main sequence". Either environmental or stellar feedback mechanisms could explain the slope of the newly defined sequence. We find the star-formation rate to be ${\rm SFR}=0.28^{+0.02}_{-0.01}{\rm M}_{\odot}{\rm yr}^{-1}$.

[43]  arXiv:2004.00439 [pdf, ps, other]

Title: Magnetic field evolution in solar-type stars

Authors: Axel Brandenburg

Comments: 13 pages, 3 figures, 3 tables, proceedings of IAU symposium 354, Solar and Stellar Magnetic Fields: Origins and Manifestations

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

We discuss selected aspects regarding the magnetic field evolution of solar-type stars. Most of the stars with activity cycles are in the range where the normalized chromospheric Calcium emission increases linearly with the inverse Rossby number. For Rossby numbers below about a quarter of the solar value, the activity saturates and no cycles have been found. For Rossby numbers above the solar value, again no activity cycles have been found, but now the activity goes up again for a major fraction of the stars. Rapidly rotating stars show nonaxisymmetric large-scale magnetic fields, but there is disagreement between models and observations regarding the actual value of the Rossby number where this happens. We also discuss the prospects of detecting the sign of magnetic helicity using various linear polarization techniques both at the stellar surface using the parity-odd contribution to linear polarization and above the surface using Faraday rotation.

[44]  arXiv:2004.00441 [pdf, other]

Title: Galactic halo size in the light of recent AMS-02 data

Authors: N. Weinrich, M. Boudaud, L. Derome, Y. Génolini, J. Lavalle, D. Maurin, P. Salati, P. Serpico, G. Weymann-Despres

Comments: 15 pages, 10 figures, 6 tables

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

The vertical diffusive halo size of the Galaxy, $L$, is a key parameter for dark matter indirect searches. It can be better determined thanks to recent AMS-02 data. We set constraints on $L$ from Be/B and $^{10}$Be/Be data, and perform a consistency check with positron data. We detail the dependence of Be/B and $^{10}$Be/Be on $L$ and forecast on which energy range better data would be helpful for future $L$ improvements. We use USINE v3.5 for the propagation of nuclei, and $e^+$ are calculated with the pinching method of Boudaud et al. (2017). The current AMS-02 Be/B ($\sim3\%$ precision) and ACE-CRIS $^{10}$Be/Be ($\sim 10\%$ precision) data bring similar and consistent constraints on $L$. The AMS-02 Be/B data alone constrain $L=5^{+3}_{-2}$ kpc at $1\sigma$, a range for which most models do not overproduce positrons. Future experiments need to deliver percent-level accuracy on $^{10}$Be/$^9$Be anywhere below 10 GV to further constrain $L$. Forthcoming AMS-02, HELIX, and PAMELA $^{10}$Be/$^9$Be results will further test and possibly tighten the limits derived here. Elemental ratios involving radioactive species with different lifetimes (e.g., Al/Mg and Cl/Ar) are also awaited to provide complementary and robuster constraints.

[45]  arXiv:2004.00454 [pdf, other]

Title: Field sources near the southern-sky calibrator PKS B1934-638: effect on spectral line observations with SKA-MID and its precursors

Authors: I. Heywood, E. Lenc, P. Serra, B. Hugo, K. W. Bannister, M. E. Bell, A. Chippendale, L. Harvey-Smith, J. Marvil, D. McConnell, M. A. Voronkov

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

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

Accurate instrumental bandpass corrections are essential for the reliable interpretation of spectral lines from targeted and survey-mode observations with radio interferometers. Bandpass correction is typically performed by comparing measurements of a strong calibrator source to an assumed model, typically an isolated point source. The wide field-of-view and high sensitivity of modern interferometers means that additional sources are often detected in observations of calibrators. This can introduce errors into bandpass corrections and subsequently the target data if not properly accounted for. Focusing on the standard calibrator PKS B1934-638, we perform simulations to asses this effect by constructing a wide-field sky model. The cases of ASKAP (0.7-1.9 GHz), MeerKAT (UHF: 0.58-1.05 GHz; L-band: 0.87-1.67 GHz) and Band 2 (0.95-1.76 GHz) of SKA-MID are examined. The use of a central point source model during bandpass calibration is found to impart amplitude errors into spectra measured by the precursor instruments at the ~0.2-0.5% level dropping to ~0.01% in the case of SKA-MID. This manifests itself as ripples in the source spectrum, the behaviour of which is coupled to the distribution of the array baselines, the solution interval, the primary beam size, the hour-angle of the calibration scan, as well as the weights used when imaging the target. Calibration pipelines should routinely employ complete field models for standard calibrators to remove this potentially destructive contaminant from the data, a recommendation we validate by comparing our simulation results to a MeerKAT scan of PKS B1934-638, calibrated with and without our expanded sky model.

[46]  arXiv:2004.00456 [pdf, other]

Title: ZTF J1901+5309: A 40.6-Minute Orbital Period Eclipsing Double White Dwarf System

Authors: Michael W. Coughlin, Kevin Burdge, E. Sterl Phinney, Jan van Roestel, Eric C. Bellm, Richard G. Dekany, Alexandre Delacroix, Dmitry A. Duev, Michael Feeney, Matthew J. Graham, S. R. Kulkarni, Thomas Kupfer, Russ R. Laher, Frank J. Masci, Thomas A. Prince, Reed Riddle, Philippe Rosnet, Roger Smith, Eugene Serabyn, Richard Walters

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

The Zwicky Transient Facility has begun to discover binary systems with orbital periods that are less than 1\,hr. Combined with dedicated follow-up systems, which allow for high-cadence photometry of these sources, systematic confirmation and characterization of these sources are now possible. Here, we report the discovery of ZTF J190125.42+530929.5, a 40.6\,min orbital period, eclipsing double white-dwarf binary. Both photometric and spectroscopic modeling confirm its nature, yielding an estimated inclination of $i = 86.2^{+0.6}_{-0.2}\,\rm degrees$ and primary and secondary effective temperatures of $\textrm{T}_\textrm{eff} = 28,000^{+500}_{-500}\,K$ and $\textrm{T}_\textrm{eff} = 17,600^{+400}_{-400}\,K$ respectively. This system adds to a growing list of sources for future gravitational-wave detectors and contributes to the demographic analysis of double degenerates.

[47]  arXiv:2004.00477 [pdf, other]

Title: Hard X-ray properties of radio-selected blazars

Authors: Marcus Langejahn, Matthias Kadler, Jörn Wilms, Eugenia Litzinger, Michael Kreter, Neil Gehrels, Wayne H. Baumgartner, Craig B. Markwardt, Jack Tueller

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

Hard X-ray properties of beamed AGN have been published in the 105-month Swift/BAT catalog, but there have not been any studies carried out so far on a well-defined, radio-selected sample of low-peaked blazars in the hard X-ray band.
Using the statistically complete MOJAVE-1 sample, we aim to determine the hard X-ray properties of radio-selected blazars, including the enigmatic gamma-ray-faint type. Also, we aim to determine the contribution of radio-selected low-peaked blazars to the diffuse CXB.
We determined photon indices, fluxes, and luminosities in the range of 20 keV - 100 keV of blazars and other extragalactic jets from the MOJAVE-1 sample, derived from the 105-month Swift/BAT survey. We calculated log N-log S distributions and the luminosity functions.
The majority of the MOJAVE-1 blazars are found to be hard X-ray emitters albeit many at low count rates. The log N-log S distribution for the hard X-ray emission of radio-selected blazars is clearly non-Euclidean, in contrast to the radio flux density distribution. Approximately 0.2% of the CXB in the 20 keV - 100 keV band can be resolved into MOJAVE-1 blazars.
The peculiar log N-log S distribution disparity might be attributed to different evolutionary paths in the X-ray and radio bands, as tested by luminosity-function modeling. X-ray variability can be ruled out as the dominant contributor. Low-peaked blazars constitute an intrinsically different source population in terms of CXB contribution compared to similar studies of X-ray-selected blazars. The hard X-ray flux and spectral index can serve as a good proxy for the gamma-ray detection probability of individual sources. Future observations combining deep X-ray survey, for example, with eROSITA, and targeted gamma-ray observations with CTA can benefit strongly from the tight connection between these high-energy bands for the different blazar sub-classes.

[48]  arXiv:2004.00511 [pdf, ps, other]

Title: Flickering of the jet-ejecting symbiotic star MWC 560

Authors: R. K. Zamanov, S. Boeva, K. A. Stoyanov, G. Latev, B. Spassov, A. Kurtenkov, G. Nikolov

Comments: 9 pages, accepted for publication in Astronomical Notes. arXiv admin note: substantial text overlap with arXiv:1807.01555

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

We analyse optical photometric data of short term variability (flickering) of the accreting white dwarf in the jet-ejecting symbiotic star MWC560. The observations are obtained in 17 nights during the period November 2011 - October 2019. The colour-magnitude diagram shows that the hot component of the system becomes redder as it gets brighter. For the flickering source we find that it has colour 0.14 < B-V < 0.40, temperature in the range 6300 < T_fl < 11000 K, and radius 1.2 < R_fl < 18 Rsun. We find a strong correlation (correlation coefficient 0.76, significance < 0.001) between B band magnitude and the average radius of the flickering source - as the brightness of the system increases the size of the flickering source also increases. The estimated temperature is similar to that of the bright spot of cataclysmic variables. In 2019 the flickering is missing, and the B-V colour of the hot component becomes bluer.

[49]  arXiv:2004.00519 [pdf, other]

Title: Chemical equilibrium in AGB atmospheres: successes, failures, and prospects for small molecules, clusters, and condensates

Authors: M. Agundez, J. I. Martinez, P. L. de Andres, J. Cernicharo, J. A. Martin-Gago

Comments: Accepted for publication in A&A. Abstract abridged

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

Chemical equilibrium has proven extremely useful to predict the chemical composition of AGB atmospheres. Here we use a recently developed code and an updated thermochemical database, including gaseous and condensed species involving 34 elements, to compute the chemical equilibrium composition of AGB atmospheres of M-, S-, and C-type stars. We include for the first time TixCy clusters, with x = 1-4 and y = 1-4, and selected larger clusters ranging up to Ti13C22, for which thermochemical data is obtained from quantum chemical calculations. We find that in general chemical equilibrium reproduces well the observed abundances of parent molecules in circumstellar envelopes of AGB stars. There are however severe discrepancies, of various orders of magnitude, for some parent molecules: HCN, CS, NH3, and SO2 in M-type stars, H2O and NH3 in S-type stars, and the hydrides H2O, NH3, SiH4, and PH3 in C-type stars. Several molecules not yet observed in AGB atmospheres, like SiC5, SiNH, SiCl, PS, HBO, and the metal-containing molecules MgS, CaS, CaOH, CaCl, CaF, ScO, ZrO, VO, FeS, CoH, and NiS, are good candidates for detection with observatories like ALMA. The first condensates predicted are carbon, TiC, and SiC in C-rich atmospheres and Al2O3 in O-rich outflows. The most probable gas-phase precursors of dust are acetylene, atomic carbon, and/or C3 for carbon dust, SiC2 and Si2C for SiC dust, and atomic Al and AlOH, AlO, and Al2O for Al2O3 dust. In the case of TiC dust, atomic Ti is probably the main supplier of titanium. However, chemical equilibrium predicts that clusters like Ti8C12 and Ti13C22 become the major reservoirs of titanium at the expense of atomic Ti in the region where condensation of TiC is expected to occur, suggesting that the assembly of large TixCy clusters could be related to the formation of the first condensation nuclei of TiC.

[50]  arXiv:2004.00610 [pdf, other]

Title: Update on Coupled Dark Energy and the $H_0$ tension

Authors: Adrià Gómez-Valent, Valeria Pettorino, Luca Amendola

Comments: 14 pages, 2 Tables, 4 Figures

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

In this work we provide updated constraints on coupled dark energy (CDE) cosmology with Peebles-Ratra (PR) potential and constant coupling strength $\beta$. This modified gravity scenario introduces a fifth force between dark matter particles, mediated by a scalar field that plays the role of dark energy. The mass of the dark matter particles does not remain constant, but changes with time as a function of the scalar field. Here we focus on the phenomenological behavior of the model, and assess its ability to describe updated cosmological data sets that include the Planck 2018 cosmic microwave background (CMB) temperature, polarization and lensing, baryon acoustic oscillations, the Pantheon compilation of supernovae of Type Ia, data on $H(z)$ from cosmic chronometers, and redshift-space distortions. We also study which is the impact of the local measurement of $H_0$ from SH0ES and the strong-lensing time delay data from the H0LICOW collaboration on the parameter that controls the strength of the interaction in the dark sector. We find a peak corresponding to a coupling $\beta > 0$ and to a potential parameter $\alpha > 0$, more or less evident depending on the data set combination. We show separately the impact of each data set and remark that it is especially CMB lensing the one data set that shifts the peak the most towards $\Lambda$CDM. When a model selection criterion based on the full Bayesian evidence is applied, however, $\Lambda$CDM is still preferred in all cases, due to the additional parameters introduced in the CDE model.

[51]  arXiv:2004.00617 [pdf, other]

Title: The Likelihood for LSS: Stochasticity of Bias Coefficients at All Orders

Authors: Giovanni Cabass, Fabian Schmidt

Comments: 10 pages

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

In the EFT of biased tracers the noise field $\varepsilon_g$ is not exactly uncorrelated with the nonlinear matter field $\delta$. Its correlation with $\delta$ is effectively captured by adding stochasticities to each bias coefficient. We show that if these stochastic fields are Gaussian (the impact of their non-Gaussianity being subleading on quasi-linear scales anyway) it is possible to resum exactly their effect on the conditional likelihood ${\cal P}[\delta_g|\delta]$ to observe a galaxy field $\delta_g$ given an underlying $\delta$. This resummation allows to take them into account in EFT-based approaches to Bayesian forward modeling. We stress that the resulting corrections to a purely Gaussian conditional likelihood with white-noise covariance are the most relevant on scales where the EFT is under control: they are more important than any non-Gaussianity of the noise $\varepsilon_g$.

[52]  arXiv:2004.00618 [pdf, other]

Title: Hot Gravitons and Gravitational Waves From Kerr Black Holes in the Early Universe

Authors: Dan Hooper, Gordan Krnjaic, John March-Russell, Samuel D. McDermott, Rudin Petrossian-Byrne

Comments: 15 pages, 6 figures

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

Any abundance of black holes that was present in the early universe will evolve as matter, making up an increasingly large fraction of the total energy density as space expands. This motivates us to consider scenarios in which the early universe included an era that was dominated by low-mass ($M < 5\times 10^8$ g) black holes which evaporate prior to primordial nucleosynthesis. In significant regions of parameter space, these black holes will become gravitationally bound within binary systems, and undergo mergers before evaporating. Such mergers result in three potentially observable signatures. First, any black holes that have undergone one or more mergers will possess substantial angular momentum, causing their Hawking evaporation to produce significant quantities of high-energy gravitons. These products of Hawking evaporation are predicted to constitute a background of hot ($\sim$eV-keV) gravitons today, with an energy density corresponding to $\Delta N_{\rm eff} \sim 0.01-0.03$. Second, these mergers will produce a stochastic background of high-frequency gravitational waves. And third, the energy density of these gravitational waves can be as large as $\Delta N_{\rm eff} \sim 0.3$, depending on the length of time between the mergers and evaporation. These signals are each potentially within the reach of future measurements.

[53]  arXiv:2004.00619 [pdf, other]

Title: Graviton non-Gaussianities and Parity Violation in the EFT of Inflation

Authors: Lorenzo Bordin, Giovanni Cabass

Comments: 17 pages (12+5)

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

We study graviton non-Gaussianities in the EFT of Inflation. At leading (second) order in derivatives, the graviton bispectrum is fixed by Einstein gravity. There are only two contributions at third order. One of them breaks parity. They come from operators that directly involve the foliation: we then expect sizable non-Gaussianities in three-point functions involving both gravitons and scalars. However, we show that at leading order in slow roll the parity-odd operator does not modify these mixed correlators. We then identify the operators that can affect the graviton bispectrum at fourth order in derivatives. There are two operators that preserve parity. We show that one gives a scalar-tensor-tensor three-point function larger than the one computed in Maldacena, 2003 if $M^2_{\rm P}A_{\rm s}/\Lambda^2\gg 1$ (where $\Lambda$ is the scale suppressing this operator and $A_{\rm s}$ the amplitude of the scalar power spectrum). There are only two parity-odd operators at this order in derivatives.

Cross-lists for Thu, 2 Apr 20

[54]  arXiv:2004.00079 (cross-list from physics.plasm-ph) [pdf]

Title: Major Scientific Challenges and Opportunities in Understanding Magnetic Reconnection and Related Explosive Phenomena throughout the Universe

Authors: H. Ji, A. Alt, S. Antiochos, S. Baalrud, S. Bale, P. M. Bellan, M. Begelman, A. Beresnyak, E.G. Blackman, D. Brennan, M. Brown, J. Buechner, J. Burch, P. Cassak, L.-J. Chen, Y. Chen, A. Chien, D. Craig, J. Dahlin, W. Daughton, E. DeLuca, C. F. Dong, S. Dorfman, J. Drake, F. Ebrahimi, J. Egedal, R. Ergun, G. Eyink, Y. Fan, G. Fiksel, C. Forest, W. Fox, D. Froula, K. Fujimoto, L. Gao, K. Genestreti, S. Gibson, M. Goldstein, F. Guo, M. Hesse, M. Hoshino, Q. Hu, Y.-M. Huang, J. Jara-Almonte, H. Karimabadi, J. Klimchuk, M. Kunz, K. Kusano, A. Lazarian, A. Le, H. Li, X. Li, Y. Lin, M. Linton, Y.-H. Liu, W. Liu, D. Longcope, N. Loureiro, Q.-M. Lu, Z-W. Ma, W. H. Matthaeus, D. Meyerhofer, F. Mozer, T. Munsat, N. A. Murphy, P. Nilson, Y. Ono, M. Opher, H. Park, S. Parker, M. Petropoulou, T. Phan, et al. (28 additional authors not shown)

Comments: 6 pages, 1 figure, white paper submitted to both Plasma 2020 and Astro 2020 Decadal Surveys

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

This white paper summarizes major scientific challenges and opportunities in understanding magnetic reconnection and related explosive phenomena as a fundamental plasma process.

[55]  arXiv:2004.00224 (cross-list from cs.DC) [pdf, other]

Title: Understanding GPU-Based Lossy Compression for Extreme-Scale Cosmological Simulations

Authors: Sian Jin, Pascal Grosset, Christopher M. Biwer, Jesus Pulido, Jiannan Tian, Dingwen Tao, James Ahrens

Comments: 11 pages, 10 figures, accepted by IEEE IPDPS '20

Subjects: Distributed, Parallel, and Cluster Computing (cs.DC); Instrumentation and Methods for Astrophysics (astro-ph.IM); Computational Physics (physics.comp-ph)

To help understand our universe better, researchers and scientists currently run extreme-scale cosmology simulations on leadership supercomputers. However, such simulations can generate large amounts of scientific data, which often result in expensive costs in data associated with data movement and storage. Lossy compression techniques have become attractive because they significantly reduce data size and can maintain high data fidelity for post-analysis. In this paper, we propose to use GPU-based lossy compression for extreme-scale cosmological simulations. Our contributions are threefold: (1) we implement multiple GPU-based lossy compressors to our opensource compression benchmark and analysis framework named Foresight; (2) we use Foresight to comprehensively evaluate the practicality of using GPU-based lossy compression on two real-world extreme-scale cosmology simulations, namely HACC and Nyx, based on a series of assessment metrics; and (3) we develop a general optimization guideline on how to determine the best-fit configurations for different lossy compressors and cosmological simulations. Experiments show that GPU-based lossy compression can provide necessary accuracy on post-analysis for cosmological simulations and high compression ratio of 5~15x on the tested datasets, as well as much higher compression and decompression throughput than CPU-based compressors.

[56]  arXiv:2004.00401 (cross-list from physics.pop-ph) [pdf, other]

Title: Conspiratorial cosmology. II. The anthropogenic principle

Authors: Jörg P. Rachen, Ute G. Gahlings (Rautavistische Universität)

Comments: 8 pages, 1 figure. Submitted to Journal of Comparative Irrelevance (Letters), scheduled to appear in Volume 42 on April 23. Community referee reports welcome until that date (ignored after) to the e-mail address given in the paper

Subjects: Popular Physics (physics.pop-ph); Cosmology and Nongalactic Astrophysics (astro-ph.CO)

We revisit our 2013 claim [arXiv:1303.7476] that the Universe is the result of a conspiratorial plot, and find that it cannot be trusted, as even the belief in this conspiracy likely results from a conspiracy. On the basis of mathematical beauty, the final results of the Planck mission, the exploration of the dark sector by means of occult rituals and symbols, and a powerful new philosophical approach to physics, we demonstrate here that not only the existence of our Universe, but the whole concept of reality has to be rejected as obsolete and generally misleading. By introducing the new concept of the "anthropogenic principle", we eventually illuminate the darkest corners of the conspiracy behind the conspiracy and briefly discuss some important implications regarding the survival of wo*mankind.

Replacements for Thu, 2 Apr 20

[57]  arXiv:1409.6757 (replaced) [pdf, ps, other]

Title: A Generalization of Gravity

Authors: Chethan Krishnan

Comments: 7 pages, v2: minor typos fixed, refs added

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)

[58]  arXiv:1707.05523 (replaced) [pdf, other]

Title: Discrimination of anisotropy in dark matter velocity distribution with directional detectors

Authors: Keiko I. Nagao, Tomonori Ikeda, Ryota Yakabe, Tatsuhiro Naka, Kentaro Miuchi

Comments: 19 pages, 34 figures

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

[59]  arXiv:1812.07437 (replaced) [pdf, other]

Title: Tomographic weak lensing bispectrum: a thorough analysis towards the next generation of galaxy surveys

Authors: Matteo Rizzato, Karim Benabed, Francis Bernardeau, Fabien Lacasa

Comments: 29 pages, 14 figures. Latest version as accepted by MNRAS

Journal-ref: MNRAS 490 (2019) 4688-4714

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

[60]  arXiv:1812.11475 (replaced) [pdf, ps, other]

Title: New ultraviolet operators in supersymmetric SO(10) GUT and consistent cosmology

Authors: Piyali Banerjee, Urjit A. Yajnik

Comments: 20 pages, 2 tables

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

[61]  arXiv:1904.04350 (replaced) [pdf, other]

Title: Modelling the Milky Way. I -- Method and first results fitting the thick disk and halo with DES-Y3 data

Authors: A. Pieres, L. Girardi, E. Balbinot, B. Santiago, L. N. da Costa, A. Carnero Rosell, A. B. Pace, K. Bechtol, M. A. T. Groenewegen, A. Drlica-Wagner, T. S. Li, M. A. G. Maia, R. L. C. Ogando, M. dal Ponte, H. T. Diehl, A. Amara, S. Avila, E. Bertin, D. Brooks, D. L. Burke, M. Carrasco Kind, J. Carretero, J. De Vicente, S. Desai, T. F. Eifler, B. Flaugher, P. Fosalba, J. Frieman, J. García-Bellido, E. Gaztanaga, D. W. Gerdes, D. Gruen, R. A. Gruendl, J. Gschwend, G. Gutierrez, D. L. Hollowood, K. Honscheid, D. J. James, K. Kuehn, N. Kuropatkin, J. L. Marshall, R. Miquel, A. A. Plazas, E. Sanchez, S. Serrano, I. Sevilla-Noarbe, E. Sheldon, M. Smith, M. Soares-Santos, F. Sobreira, E. Suchyta, M. E. C. Swanson, G. Tarle, D. Thomas, V. Vikram, A. R. Walker

Comments: 18 pages, 6 figures

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

[62]  arXiv:1904.04570 (replaced) [pdf, other]

Title: Bursts of Gravitational Waves due to Crustquake from Pulsars

Authors: Biswanath Layek, Pradeepkumar Yadav

Comments: 8 pages, 2 figures, 1 table. Accepted for publication in Journal of Astrophysics and Astronomy. Comments are welcome!

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

[63]  arXiv:1904.05699 (replaced) [pdf, other]

Title: Higgs inflation in metric and Palatini formalisms: Required suppression of higher dimensional operators

Authors: Ryusuke Jinno, Mio Kubota, Kin-ya Oda, Seong Chan Park

Comments: 29 pages, 10 figures; minor typo correction; references added

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

[64]  arXiv:1906.11855 (replaced) [pdf, other]

Title: Population synthesis of black hole binary mergers from star clusters

Authors: Fabio Antonini, Mark Gieles

Comments: Accepted for publication in MNRAS

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

[65]  arXiv:1908.09409 (replaced) [pdf, ps, other]

Title: Electric and magnetic axion quark nuggets, their stability and their detection

Authors: O. Santillan, M. Sempe

Comments: Some further comments added

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

[66]  arXiv:1909.00718 (replaced) [pdf, other]

Title: Optimizing exoplanet atmosphere retrieval using unsupervised machine-learning classification

Authors: Joshua J.C. Hayes, E. Kerins, S. Awiphan, I. McDonald, J.S. Morgan, P. Chuanraksasat, S. Komonjinda, N. Sanguansak, P. Kittara (SPEARNET)

Comments: Accepted for publication in MNRAS

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

[67]  arXiv:1909.01993 (replaced) [pdf, ps, other]

Title: Implications of a proton blazar inspired model on correlated observations of neutrinos with gamma-ray flaring blazars

Authors: Prabir Banik, Arunava Bhadra, Madhurima Pandey, Debasish Majumdar

Comments: 12 pages, four figures. arXiv admin note: text overlap with arXiv:1908.11849

Journal-ref: Physical Review D, 101, 063024 (2020)

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

[68]  arXiv:1909.04690 (replaced) [pdf, other]

Title: Probing gaseous galactic halos through the rotational kSZ effect

Authors: José Manuel Zorrilla Matilla, Zoltán Haiman

Comments: 19 pages, 12 figures. Accepted to PRD

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

[69]  arXiv:1910.07905 (replaced) [pdf, ps, other]

Title: Material matter effects in gravitational UV/IR mixing

Authors: Joseph Bramante, Elizabeth Gould

Comments: 10 pages, no figures, PRD version

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)

[70]  arXiv:1910.09566 (replaced) [pdf, other]

Title: Galactic outflow rates in the EAGLE simulations

Authors: Peter D. Mitchell, Joop Schaye, Richard G. Bower, Robert A. Crain

Comments: MNRAS accepted

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

[71]  arXiv:1911.01432 (replaced) [pdf, other]

Title: QCD Baryogenesis

Authors: Djuna Croon, Jessica N. Howard, Seyda Ipek, Timothy M.P. Tait

Comments: 23 pages, 8 figures. Published version

Journal-ref: Phys. Rev. D 101 (2020) 5, 055042

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

[72]  arXiv:1912.01061 (replaced) [pdf, other]

Title: On the slope of curvature power spectrum in non-attractor inflation

Authors: Ogan Özsoy (1 and 2), Gianmassimo Tasinato (1) ((1) Swansea University, (2) Warsaw University)

Comments: 61 pages, 17 figures, v3, Accepted to JCAP, discussion in section 2 is revised and improved, New appendix (Appendix A) added to generalize the evolution of curvature perturbation on super-horizon scales with arbitrary boundary conditions. Results did not change

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)

[73]  arXiv:1912.06478 (replaced) [pdf, ps, other]

Title: The quantum black hole as a gravitational hydrogen atom

Authors: Christian Corda, Fabiano Feleppa

Comments: 20 pages

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

[74]  arXiv:1912.07326 (replaced) [pdf, other]

Title: Euclid: The reduced shear approximation and magnification bias for Stage IV cosmic shear experiments

Authors: A.C. Deshpande, T.D. Kitching, V.F. Cardone, P.L. Taylor, S. Casas, S. Camera, C. Carbone, M. Kilbinger, V. Pettorino, Z. Sakr, D. Sapone, I. Tutusaus, N. Auricchio, C. Bodendorf, D. Bonino, M. Brescia, V. Capobianco, J. Carretero, M. Castellano, S. Cavuoti, R. Cledassou, G. Congedo, L. Conversi, L. Corcione, M. Cropper, F. Dubath, S. Dusini, G. Fabbian, E. Franceschi, M. Fumana, B. Garilli, F. Grupp, H. Hoekstra, F. Hormuth, H. Israel, K. Jahnke, S. Kermiche, B. Kubik, M. Kunz, F. Lacasa, S. Ligori, P.B. Lilje, I. Lloro, E. Maiorano, O. Marggraf, R. Massey, S. Mei, M. Meneghetti, G. Meylan, L. Moscardini, C. Padilla, S. Paltani, F. Pasian, S. Pires, G. Polenta, M. Poncet, F. Raison, J. Rhodes, M. Roncarelli, R. Saglia, P. Schneider, A. Secroun, S. Serrano, G. Sirri, J.L. Starck, F. Sureau, et al. (6 additional authors not shown)

Comments: 16 pages, 6 figures, submitted to Astronomy & Astrophysics on 16/12/2019, accepted on 04/03/2020. SSC Fisher procedure corrected

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

[75]  arXiv:2001.10645 (replaced) [pdf, other]

Title: The Formation Height of Millimeter-wavelength Emission in the Solar Chromosphere

Authors: Juan Martinez-Sykora, Bart De Pontieu, Jaime de la Cruz Rodriguez, Georgios Chintzoglou

Comments: 5 figures under review in ApJL

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

[76]  arXiv:2002.01573 (replaced) [pdf, other]

Title: Astronomical Applications of Multi-Core Fiber Technology

Authors: Nemanja Jovanovic, Robert J. Harris, Nick Cvetojevic

Comments: 10 pages, 5 figures

Journal-ref: IEEE Journal of Selected Topics in Quantum Electronics, Vol 26, No. 4, 2020

Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Optics (physics.optics)

[77]  arXiv:2002.02549 (replaced) [pdf]

Title: The Impact of Planetary Rotation Rate on the Reflectance and Thermal Emission Spectrum of Terrestrial Exoplanets Around Sun-like Stars

Authors: Scott D. Guzewich, Jacob Lustig-Yaeger, Christopher Evan Davis, Ravi Kumar Kopparapu, Michael J. Way, Victoria S. Meadows

Comments: Accepted to The Astrophysical Journal

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

[78]  arXiv:2002.10951 (replaced) [src]

Title: A Fluctuation Dissipation Relation for Relativistic stars

Authors: Seema Satin

Comments: arXiv admin note: text overlap with arXiv:1711.06859..... some flaw in the assumption for solution of the equations has been found, which is a non-trivial mistake, hence needs to be worked upon again with correct assumptions, and see if this work can progress with analytical closed form results or needs numerical work. Major modifications needed for the mathematics worked out here

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

[79]  arXiv:2003.05493 (replaced) [pdf, other]

Title: The $γ$-ray Emission of Star-Forming Galaxies

Authors: M. Ajello, M. Di Mauro, V. S. Paliya, S. Garrappa

Comments: Accepted for publication in The Astrophysical Journal

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

[80]  arXiv:2003.07788 (replaced) [pdf, ps, other]

Title: Black holes in the four-dimensional Einstein-Lovelock gravity

Authors: R. A. Konoplya, A. Zhidenko

Comments: 5 pages, 1 ancillary Mathematica(R) notebook, minor changes, references added - the version accepted for publication in Physical Review D

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

[81]  arXiv:2003.09825 (replaced) [pdf, other]

Title: Reconstruction of Radio Relics and X-ray Tails in an Off-axis Cluster Merger: Hydrodynamical Simulations of A115

Authors: Wonki Lee, M. James Jee, Hyesung Kang, Dongsu Ryu, Taysun Kimm, Marcus Brüggen

Comments: 14 pages, 11 figures, ApJ in press

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

[82]  arXiv:2003.11901 (replaced) [pdf, other]

Title: Gravitational waves and mass ejecta from binary neutron star mergers: Effect of the spin orientation

Authors: Swami Vivekanandji Chaurasia, Tim Dietrich, Maximiliano Ujevic, Kai Hendriks, Reetika Dudi, Francesco Maria Fabbri, Wolfgang Tichy, Bernd Brügmann

Comments: 17 pages, 15 figures

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

[83]  arXiv:2003.12512 (replaced) [pdf]

Title: SKA1-LOW Antenna Design Document

Authors: Eloy de Lera Acedo, Hardie Pienaar

Comments: 44 pages, 43 figures

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

[84]  arXiv:2003.12561 (replaced) [pdf, other]

Title: The 3D non-LTE solar nitrogen abundance from atomic lines

Authors: A. M. Amarsi, N. Grevesse, J. Grumer, M. Asplund, P. S. Barklem, R. Collet

Comments: 11 pages, 7 figures, 3 tables; accepted for publication in Astronomy & Astrophysics

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

[85]  arXiv:2003.12744 (replaced) [pdf]

Title: SKA LFAA Station Design Report

Authors: Eloy de Lera Acedo, Hardie Pienaar, Nima Razavi Ghods, Jens Abraham, Edgar Colin Beltran, Ben Mort, Fred Dulwich, Giuseppe Virone, Benedetta Fiorelli, Michiel Arts, Christophe Craeye, Bui van Ha, Keith Grainge, Peter Dewdney, Jeff Wagg, Maria Grazia Labate, Andrew Faulkner, Jan Geralt bij de Vaate, Marchel Gerbers

Comments: 129 pages, 129 figures

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

[86]  arXiv:2003.13705 (replaced) [pdf, other]

Title: The Fornax 3D project: Globular clusters tracing kinematics and metallicities

Authors: K. Fahrion, M. Lyubenova, M. Hilker, G. van de Ven, J. Falcón-Barroso, R. Leaman, I. Martín-Navarro, A. Bittner, L. Coccato, E. M. Corsini, D. A. Gadotti, E. Iodice, R. M. McDermid, F. Pinna, M. Sarzi, S. Viaene, P. T. de Zeeuw, L. Zhu

Comments: 13 pages + appendix, accepted for publication in A&A, updated references

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

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