We gratefully acknowledge support from
the Simons Foundation and Leiden University.

Astrophysics

New submissions

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New submissions for Thu, 28 May 20

[1]  arXiv:2005.12906 [pdf, ps, other]
Title: SIRIUS project I: Star formation models for star-by-star simulations of star clusters and galaxy formation
Comments: 14 pages, 11 figures, submitted to PASJ
Subjects: Astrophysics of Galaxies (astro-ph.GA); Instrumentation and Methods for Astrophysics (astro-ph.IM); Solar and Stellar Astrophysics (astro-ph.SR)

Most stars are formed as star clusters in galaxies, which then disperse into galactic disks. Upcoming exascale supercomputational facilities will enable performing simulations of galaxies and their formation by resolving individual stars (star-by-star simulations). This will substantially advance our understanding of star formation in galaxies, star cluster formation, and assembly histories of galaxies. In previous galaxy simulations, a simple stellar population approximation was used. It is, however, difficult to improve the mass resolution with this approximation. Therefore, a model for forming individual stars that can be used in simulations of galaxies must be established. In this first paper of a series of the SIRIUS (SImulations Resolving IndividUal Stars) project, we propose and demonstrate a new stochastic star formation model for star-by-star simulations. In this model, an assumed stellar initial mass function (IMF) is randomly assigned to newly formed stars. We then introduce a maximum search radius to assemble the mass from surrounding gas particles to form star particles. In this study, we perform a series of $N$-body/smoothed particle hydrodynamics simulations of star cluster formations from turbulent molecular clouds as test cases. The IMF can be correctly sampled if a maximum search radius that is larger than the value estimated from the threshold density for star formation is adopted. In small clouds, the formation of massive stars is highly stochastic because of the small number of stars. We confirm that the star formation efficiency and threshold density do not strongly affect the results. Herein, we demonstrate that our models can be applied to simulations varying from star clusters to galaxies for a wide range of resolutions.

[2]  arXiv:2005.12916 [pdf, other]
Title: Pressure balance in the multiphase ISM of cosmologically simulated disk galaxies
Comments: 20 pages, 14 figures, submitted to MNRAS
Subjects: Astrophysics of Galaxies (astro-ph.GA)

Pressure balance plays a central role in models of the interstellar medium (ISM), but whether and how pressure balance is realized in a realistic multiphase ISM is not yet well understood. We address this question using a set of FIRE-2 cosmological zoom-in simulations of Milky Way-mass disk galaxies, in which a multiphase ISM is self-consistently shaped by gravity, cooling, and stellar feedback. We analyze how gravity determines the vertical pressure profile as well as how the total ISM pressure is partitioned between different phases and components (thermal, dispersion/turbulence, and bulk flows). We show that, on average and consistent with previous more idealized simulations, the total ISM pressure balances the weight of the overlying gas. Deviations from vertical pressure balance increase with increasing galactocentric radius and with decreasing averaging scale. The different phases are in rough total pressure equilibrium with one another, but with large deviations from thermal pressure equilibrium owing to kinetic support in the cold and warm phases, which dominate the total pressure near the midplane. Bulk flows (e.g., inflows and fountains) are important at a few disk scale heights, while thermal pressure from hot gas dominates at larger heights. Overall, the total midplane pressure is well-predicted by the weight of the disk gas, and we show that it also scales linearly with the star formation rate surface density (Sigma_SFR). These results support the notion that the Kennicutt-Schmidt relation arises because Sigma_SFR and the gas surface density (Sigma_g) are connected via the ISM midplane pressure.

[3]  arXiv:2005.12919 [pdf, other]
Title: Probing the nature of dark matter with accreted globular cluster streams
Comments: 23 pages, 14 figures, 1 table
Subjects: Astrophysics of Galaxies (astro-ph.GA)

The steepness of the central density profiles of dark matter (DM) in low-mass galaxy halos (e.g. dwarf galaxies) is a powerful probe of the nature of DM. We propose a novel scheme to probe the inner profiles of galaxy subhalos using stellar streams. We show that the present day morphological and dynamical properties of accreted globular cluster (GC) streams - those produced from tidal stripping of GCs that initially evolved within satellite galaxies and later merged with the Milky Way (MW) - are sensitive to the central DM density profile and mass of their parent satellites. GCs that accrete within cuspy CDM subhalos produce streams that are physically wider and dynamically hotter than streams that accrete inside cored subhalos. A first comparison of MW streams "GD-1" and "Jhelum" (likely of accreted GC origin) with our simulations indicates a preference for cored subhalos. If these results hold up in future data, the implication is that either the DM cusps were erased by baryonic feedback, or their subhalos naturally possessed cored density profiles implying DM models beyond CDM. Moreover, accreted GC streams are highly structured and exhibit complex morphological features (e.g., parallel structures and "spurs"). This implies that the accretion scenario can naturally explain the recently observed peculiarities in some of the MW streams. We also propose a novel mechanism for forming "gaps" in streams when the remnant of the parent subhalo later passes through the stream. This encounter can last a longer time (and have more of an impact) than the random encounters with DM subhalos previously considered, because the GC stream and its parent subhalo are on similar orbits with small relative velocities. Current and future surveys of the MW halo will uncover numerous faint stellar streams and provide the data needed to substantiate our preliminary tests with this new probe of DM.

[4]  arXiv:2005.12920 [pdf, other]
Title: Illuminating a tadpole's metamorphosis II: observing the on-going transformation with ALMA
Comments: MNRAS, accepted
Subjects: Astrophysics of Galaxies (astro-ph.GA); Solar and Stellar Astrophysics (astro-ph.SR)

We present new Atacama Large Millimeter/submillimeter Array (ALMA) observations of the tadpole, a small globule in the Carina Nebula that hosts the HH 900 jet+outflow system. Our data include $^{12}$CO, $^{13}$CO, C$^{18}$O J=2-1, $^{13}$CO, C$^{18}$O J=3-2, and serendipitous detections of DCN J=3-2 and CS J=7-6. With angular resolution comparable to the Hubble Space Telescope (HST), our data reveal for the first time the bipolar molecular outflow in CO, seen only inside the globule, that is launched from the previously unseen jet-driving protostar (the HH 900 YSO). The biconical morphology joins smoothly with the externally irradiated outflow seen in ionized gas tracers outside the globule, tracing the overall morphology of a jet-driven molecular outflow. Continuum emission at the location of the HH 900 YSO appears to be slightly flattened perpendicular to outflow axis. Model fits to the continuum have a best-fit spectral index of $\sim 2$, suggesting cold dust and the onset of grain growth. In position-velocity space, $^{13}$CO and C$^{18}$O gas kinematics trace a C-shaped morphology, similar to infall profiles seen in other sources, although the global dynamical behaviour of the gas remains unclear. Line profiles of the CO isotopologues display features consistent with externally heated gas. We estimate a globule mass of $\sim 1.9$ M$_{\odot}$, indicating a remaining lifetime of $\sim 4$ Myr, assuming a constant photoevaporation rate. This long globule lifetime will shield the disk from external irradiation perhaps prolonging its life and enabling planet formation in regions where disks are typically rapidly destroyed.

[5]  arXiv:2005.12921 [pdf, other]
Title: Outflows, Cores and Magnetic Field Orientations in W43-MM1 as seen by ALMA
Comments: Accepted by A&A, 10 pages, 4 figures
Subjects: Astrophysics of Galaxies (astro-ph.GA)

It has been proposed that the magnetic field, pervasive in the ISM, plays an important role in the process of massive star formation. To better understand its impact at the pre and protostellar stages, high-angular resolution observations of polarized dust emission toward a large sample of massive dense cores are needed. To this end, we used the Atacama Large Millimeter Array in Band 6 (1.3 mm) in full polarization mode to map the polarized emission from dust grains at a physical scale of $\sim$2700 au in the massive protocluster W43-MM1. We used these data to measure the orientation of the magnetic field at the core scale. Then, we examined the relative orientations of the core-scale magnetic field, of the protostellar outflows determined from CO molecular line emission, and of the major axis of the dense cores determined from 2D Gaussian fit in the continuum emission. We found that the orientation of the dense cores is not random with respect to the magnetic field. Instead, the dense cores are compatible with being oriented 20-50$^\deg$ with respect to the magnetic field. The outflows could be oriented 50-70$^\deg$ with respect to the magnetic field, or randomly oriented with respect to the magnetic field, similar to current results in low-mass star-forming regions. In conclusion, the observed alignment of the position angle of the cores with respect to the magnetic field lines shows that the magnetic field is well coupled with the dense material; however, the 20-50$^\deg$ preferential orientation contradicts the predictions of the magnetically-controlled core-collapse models. The potential correlation of the outflow directions with respect to the magnetic field suggests that, in some cases, the magnetic field is strong enough to control the angular momentum distribution from the core scale down to the inner part of the circumstellar disks where outflows are triggered.

[6]  arXiv:2005.12922 [pdf, other]
Title: SN2019dge: a Helium-rich Ultra-Stripped Envelope Supernova
Comments: 29 pages, 23 figures, submitted to ApJ
Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)

We present observations of ZTF18abfcmjw (SN2019dge), a helium-rich supernova with a fast-evolving light curve indicating an extremely low ejecta mass ($\approx 0.3\,M_\odot$) and low kinetic energy ($\approx 1.2\times 10^{50}\,{\rm erg}$). Early-time (<4 d after explosion) photometry reveal evidence of shock cooling from an extended helium-rich envelope of $\sim0.1\,M_\odot$ located at $\sim 3\times 10^{12}\,{\rm cm}$ from the progenitor. Early-time He II line emission and subsequent spectra show signatures of interaction with helium-rich circumstellar material, which extends from $\gtrsim 5\times 10^{13}\,{\rm cm}$ to $\gtrsim 2\times 10^{16}\,{\rm cm}$. We interpret SN2019dge as a helium-rich supernova from an ultra-stripped progenitor, which originates from a close binary system consisting of a mass-losing helium star and a low-mass main sequence star or a compact object (i.e., a white dwarf, a neutron star, or a black hole). We infer that the local volumetric birth rate of 19dge-like ultra-stripped SNe is in the range of 1400--8200$\,{\rm Gpc^{-3}\, yr^{-1}}$ (i.e., 2--12% of core-collapse supernova rate). This can be compared to the observed coalescence rate of compact neutron star binaries that are not formed by dynamical capture.

[7]  arXiv:2005.12926 [pdf, other]
Title: The origin of X-ray coronae around simulated disc galaxies
Comments: 18 pages, 11 figures, submitted to MNRAS
Subjects: Astrophysics of Galaxies (astro-ph.GA)

The existence of hot, accreted gaseous coronae around massive galaxies is a long-standing central prediction of galaxy formation models in the $\Lambda$CDM cosmology. While observations now confirm that extraplanar hot gas is present around late-type galaxies, the origin of the gas is uncertain with suggestions that galactic feedback could be the dominant source of energy powering the emission. We investigate the origin and X-ray properties of the hot gas that surrounds galaxies of halo mass, $(10^{11}-10^{14}) \mathrm{M}_\odot$, in the cosmological hydrodynamical EAGLE simulations. We find that the central X-ray emission, $\leq 0.10 R_{\mathrm{vir}}$, of halos of mass $\leq 10^{13} \mathrm{M}_\odot$ originates from gas heated by supernovae (SNe). However, beyond this region, a quasi-hydrostatic, accreted atmosphere dominates the X-ray emission in halos of mass $\geq 10^{12} \mathrm{M}_\odot$. We predict that a dependence on halo mass of the hot gas to dark matter mass fraction can significantly change the slope of the $L_{\mathrm{X}}-M_{\mathrm{vir}}$ relation (which is typically assumed to be $4/3$ for clusters) and we derive the scaling law appropriate to this case. As the gas fraction in halos increases with halo mass, we find a steeper slope for the $L_{\mathrm{X}}-M_{\mathrm{vir}}$ in lower mass halos, $\leq 10^{14} \mathrm{M}_\odot$. This varying gas fraction is driven by active galactic nuclei (AGN) feedback. We also identify the physical origin of the so-called "missing feedback" problem, the apparently low X-ray luminosities observed from high star-forming, low-mass galaxies. This is explained by the ejection of SNe-heated gas from the central regions of the halo.

[8]  arXiv:2005.12927 [pdf, ps, other]
Title: Application of X-Ray Clumpy Torus Model (XCLUMPY) to 10 Obscured Active Galactic Nuclei Observed with Suzaku and NuSTAR
Comments: 17 pages, 3 figures, accepted for publication in ApJ
Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); Astrophysics of Galaxies (astro-ph.GA)

We apply XCLUMPY, an X-ray spectral model from a clumpy torus in an active galactic nucleus (AGN), to the broadband X-ray spectra of 10 obscured AGNs observed with both Suzaku and NuSTAR. The infrared spectra of these AGNs were analyzed with the CLUMPY code. Since XCLUMPY adopts the same clump distribution as that in the CLUMPY, we can directly compare the torus parameters obtained from the X-ray spectra and those from the infrared ones. The torus angular widths determined from the infrared spectra ($\sigma_{\mathrm{IR}}$) are systematically larger than those from the X-ray data ($\sigma_{\mathrm{X}}$); the difference ($\sigma_{\mathrm{IR}}-\sigma_{\mathrm{X}}$) correlates with the inclination angle determined from the X-ray spectrum. These results can be explained by the contribution from dusty polar outflows to the observed infrared flux, which becomes more significant at higher inclinations (more edge-on views). The ratio of the hydrogen column density and V-band extinction in the line of sight absorber shows large scatter ($\simeq$1 dex) around the Galactic value, suggesting that a significant fraction of AGNs have dust-rich circumnuclear environments.

[9]  arXiv:2005.12928 [pdf, other]
Title: A hierarchical field-level inference approach to reconstruction from sparse Lyman-$α$ forest data
Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Instrumentation and Methods for Astrophysics (astro-ph.IM)

We address the problem of inferring the three-dimensional matter distribution from a sparse set of one-dimensional quasar absorption spectra of the Lyman-$\alpha$ forest. Using a Bayesian forward modelling approach, we focus on extending the dynamical model to a fully self-consistent hierarchical field-level prediction of redshift-space quasar absorption sightlines. Our field-level approach rests on a recently developed semiclassical analogue to Lagrangian perturbation theory (LPT), which improves over noise problems and interpolation requirements of LPT. It furthermore allows for a manifestly conservative mapping of the optical depth to redshift space. In addition, this new dynamical model naturally introduces a coarse-graining scale, which we exploit to accelerate the MCMC sampler using simulated annealing. By gradually reducing the effective temperature of the forward model, we can allow it to converge first on large spatial scales before the sampler becomes sensitive to the increasingly larger space of smaller scales. We demonstrate the advantages -- in terms of speed and noise properties -- of this field-level approach over using LPT as a forward model, and, using mock data, validate its performance to reconstruct three-dimensional primordial perturbations and matter distribution from sparse quasar sightlines.

[10]  arXiv:2005.12931 [pdf, other]
Title: Determining the systemic redshift of Lyman-α emitters with neural networks and improving the measured large-scale clustering
Comments: 22 Pages, 20 figures, a lot of fun
Subjects: Astrophysics of Galaxies (astro-ph.GA)

We explore how to mitigate the clustering distortions in Lyman-$\alpha$ emitters (LAEs) samples caused by the miss-identification of the Lyman-$\alpha$ (Ly$\alpha$) wavelength in their Ly$\alpha$ line profiles. We use the Ly$\alpha$ line profiles from our previous LAE theoretical model that includes radiative transfer in the interstellar and intergalactic mediums. We introduce a novel approach to measure the systemic redshift of LAEs from their Ly$\alpha$ line using neural networks. In detail, we assume that, for a fraction of the whole LAE population their systemic redshift is determined precisely through other spectral features. We then use this subset to train a neural network that predicts the Ly$\alpha$ wavelength given a Ly$\alpha$ line profile. We test two different training sets: i) the LAEs are selected homogeneously and ii) only the brightest LAEs are selected. In comparison with previous approaches in the literature, our methodology improves significantly both accuracy and precision in determining the Ly$\alpha$ wavelength. In fact, after applying our algorithm in ideal Ly$\alpha$ line profiles, we recover the clustering unperturbed down to 1cMpc/h. Then, we test the performance of our methodology in realistic Ly$\alpha$ line profiles by downgrading their quality. The machine learning techniques work well even if the Ly$\alpha$ line profile quality is decreased considerably. We conclude that LAE surveys such as HETDEX would benefit from determining with high accuracy the systemic redshift of a subpopulation and applying our methodology to estimate the systemic redshift of the rest of the galaxy sample.

[11]  arXiv:2005.12932 [pdf, other]
Title: Evidence that 1I/2017 U1 (`Oumuamua) was composed of molecular hydrogen ice
Comments: Accepted for publication in ApJL, 8 pages, 2 figures. All software is available at this https URL
Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Astrophysics of Galaxies (astro-ph.GA)

`Oumuamua (I1 2017) was the first macroscopic ($l\sim100\,{\rm m}$) body observed to traverse the inner solar system on an unbound hyperbolic orbit. Its light curve displayed strong periodic variation, and it showed no hint of a coma or emission from molecular outgassing. Astrometric measurements indicate that 'Oumuamua experienced non-gravitational acceleration on its outbound trajectory, but energy balance arguments indicate this acceleration is inconsistent with a water ice sublimation-driven jet of the type exhibited by solar system comets. We show that all of `Oumaumua's observed properties can be explained if it contained a significant fraction of molecular hydrogen (H$_{2}$) ice. H$_{2}$ sublimation at a rate proportional to the incident solar flux generates a surface-covering jet that reproduces the observed acceleration. Mass wasting from sublimation leads to monotonic increase in the body axis ratio, explaining `Oumuamua's shape. Back-tracing `Oumuamua's trajectory through the Solar System permits calculation of its mass and aspect ratio prior to encountering the Sun. We show that H$_{2}$-rich bodies plausibly form in the coldest dense cores of Giant Molecular Clouds, where number densities are of order $n\sim10^5$, and temperatures approach the $T=3\,{\rm K}$ background. Post-formation exposure to galactic cosmic rays implies a $\tau \sim 100$ Myr age, explaining the kinematics of `Oumuamua's inbound trajectory.

[12]  arXiv:2005.12933 [pdf, other]
Title: Connecting the structure of dark matter haloes to the primordial power spectrum
Comments: 20 pages, 15 figures, accepted for publication in MNRAS
Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Astrophysics of Galaxies (astro-ph.GA)

A large body of work based on collisionless cosmological N-body simulations going back over two decades has advanced the idea that collapsed dark matter haloes have simple and approximately universal forms for their mass density and pseudo-phase space density (PPSD) distributions. However, a general consensus on the physical origin of these results has not yet been reached. In the present study, we explore to what extent the apparent universality of these forms holds when we vary the initial conditions (i.e., the primordial power spectrum of density fluctuations) away from the standard CMB-normalised case, but still within the context of LCDM with a fixed expansion history. Using simulations that vary the initial amplitude and shape, we show that the structure of dark matter haloes retains a clear memory of the initial conditions. Specifically, increasing (lowering) the amplitude of fluctuations increases (decreases) the concentration of haloes and, if pushed far enough, the density profiles deviate strongly from the NFW form that is a good approximation for the CMB-normalised case. Although, an Einasto form works well. Rather than being universal, the slope of the PPSD (or pseudo-entropy) profile steepens (flattens) with increasing (decreasing) power spectrum amplitude and can exhibit a strong halo mass dependence. Our results therefore indicate that the previously identified universality of the structure of dark matter haloes is mostly a consequence of adopting a narrow range of (CMB-normalised) initial conditions for the simulations. Our new suite provides a useful test-bench against which physical models for the origin of halo structure can be validated.

[13]  arXiv:2005.12948 [pdf, other]
Title: Inside Out and Upside-Down: The Roles of Gas Cooling and Dynamical Heating in Shaping the Stellar Age-Velocity Relation
Comments: Submitting to MNRAS. Comments welcomed. This simulation is publicly available. Contact Alyson Brooks for details
Subjects: Astrophysics of Galaxies (astro-ph.GA)

Kinematic studies of disk galaxies, using individual stars in the Milky Way or statistical studies of global disk kinematics over time, provide insight into how disks form and evolve. We use a high-resolution, cosmological zoom-simulation of a Milky Way-mass disk galaxy h277 to tie together local disk kinematics and the evolution of the disk over time. The present-day stellar age-velocity relationship (AVR) of h277 is nearly identical to that of the analogous solar-neighborhood measurement in the Milky Way. A crucial element of this success is the simulation's dynamically cold multi-phase ISM, which allows young stars to form with a low velocity dispersion ($\sigma_{\mathrm{birth}}$$\sim 6 - 8\ \mathrm{km}\, \mathrm{s}^{-1}$) at late times. Older stars are born kinematically hotter (i.e., the disk settles over time in an "upside-down" formation scenario), and are subsequently heated after birth. The disk also grows "inside-out", and many of the older stars in the solar neighborhood at $z=0$ are present because of radial mixing. We demonstrate that the evolution of $\sigma_{\mathrm{birth}}$ in h277 can be explained by the same model used to describe the general decrease in velocity dispersion observed in disk galaxies from $z\sim 2-3$ to the present-day, in which the disk evolves in quasi-stable equilibrium and the ISM velocity dispersion decreases over time due to a decreasing gas fraction. Thus, our results tie together local observations of the Milky Way's AVR with observed kinematics of high $z$ disk galaxies.

[14]  arXiv:2005.12950 [pdf, other]
Title: Evidence of AGN feedback and sloshing in the X-ray luminous NGC 1550 galaxy group
Comments: Accepted for publication in MNRAS, 17 pages with 13 figures and 10 tables
Subjects: Astrophysics of Galaxies (astro-ph.GA); High Energy Astrophysical Phenomena (astro-ph.HE)

We present results from GMRT and Chandra observations of the NGC 1550 galaxy group. Although previously thought of as relaxed, we show evidence that gas sloshing and active galactic nucleus (AGN) heating have affected the structure of the system. The 610 and 235 MHz radio images show an asymmetric jet-lobe structure with a total size of $\sim$33 kpc, with a sharp kink at the base of the more extended western jet, and bending of the shorter eastern jet as it enters the lobe. The 235$-$610 MHz spectral index map shows that both radio lobes have steep spectral indices ($\alpha_{235}^{610}\geq-1.5$) indicating the presence of an old electron population. The X-ray images reveal an asymmetric structure in the hot gas correlated with the radio structure, as well as potential cavities coincident with the radio lobes, with rims and arms of gas that may have been uplifted by the cavity expansion. The X-ray residual map reveals an arc shaped structure to the east that resembles a sloshing cold front. Radio spectral analysis suggests a radiative age of about 33 Myr for the source, comparable to the sloshing timescale and dynamical estimates of the age of the lobes. An estimate of the mechanical energy required to inflate the cavities suggests that the AGN of NGC 1550 is capable of balancing radiative losses from the intragroup medium (IGM) and preventing excessive cooling, providing that the AGN jets are efficiently coupled to the IGM gas. In conclusion, we find evidence of sloshing motions from both radio and X-ray structures, suggesting that NGC 1550 was perturbed by a minor merger or infalling galaxy about 33 Myr ago.

[15]  arXiv:2005.12958 [pdf, other]
Title: Shining X-rays on asymptotically safe quantum gravity
Comments: 9 pages, 4 figures. arXiv admin note: text overlap with arXiv:2005.00184
Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Theory (hep-th)

Asymptotically safe quantum gravity is a promising candidate scenario to provide a UV extension for the effective quantum field theory of Einstein's gravity. The theory has its foundations on the very successful framework of quantum field theory, which has been extensively tested for electromagnetic and nuclear interactions. However, observational tests of asymptotically safe quantum gravity are more challenging. Recently, a rotating black hole metric inspired by asymptotically safe quantum gravity has been proposed, and this opens the possibility of astrophysical tests of the theory. In the present paper, we show the capabilities of X-ray reflection spectroscopy to constrain the inverse dimensionless fixed-point value $\gamma$ from the analysis of a Suzaku observation of the X-ray binary GRS 1915+105. We compare these constraints with those obtained from black hole imaging.

[16]  arXiv:2005.13002 [pdf, other]
Title: Implications of different stellar spectra for the climate of tidally-locked Earth-like exoplanets
Comments: 12 pages, 8 figures
Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)

The majority of potentially habitable exoplanets detected orbit stars cooler than the Sun, and therefore are irradiated by a stellar spectrum peaking at longer wavelengths than that incident on Earth. Here, we present results from a set of simulations of tidally-locked terrestrial planets orbiting three different host stars to isolate the effect of the stellar spectra on the simulated climate. Specifically, we perform simulations based on TRAPPIST-1e, adopting an Earth-like atmosphere and using the UK Met Office Unified Model in an idealised 'aqua-planet' configuration. Whilst holding the planetary parameters constant, including the total stellar flux (900 W/m$^2$) and orbital period (6.10 Earth days), we compare results between simulations where the stellar spectrum is that of a quiescent TRAPPIST-1, Proxima Centauri and the Sun. The simulations with cooler host stars had an increased proportion of incident stellar radiation absorbed directly by the troposphere compared to the surface. This, in turn, led to an increase in the stability against convection, a reduction in overall cloud coverage on the dayside (reducing scattering), leading to warmer surface temperatures. The increased direct heating of the troposphere also led to more efficient heat transport from the dayside to the nightside and, therefore, a reduced day-night temperature contrast. We inferred that planets with an Earth-like atmosphere orbiting cooler stars had lower dayside cloud coverage, potentially allowing habitable conditions at increased orbital radii, compared to similar planets orbiting hotter stars for a given planetary rotation rate.

[17]  arXiv:2005.13025 [pdf, other]
Title: 21st Century Statistical and Computational Challenges in Astrophysics
Comments: Accepted for publication in volume 8 of Annual Reviews of Statistics and Its Application. 26 pages, 7 figures
Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM)

Modern astronomy has been rapidly increasing our ability to see deeper into the universe, acquiring enormous samples of cosmic populations. Gaining astrophysical insights from these datasets requires a wide range of sophisticated statistical and machine learning methods. Long-standing problems in cosmology include characterization of galaxy clustering and estimation of galaxy distances from photometric colors. Bayesian inference, central to linking astronomical data to nonlinear astrophysical models, addresses problems in solar physics, properties of star clusters, and exoplanet systems. Likelihood-free methods are growing in importance. Detection of faint signals in complicated noise is needed to find periodic behaviors in stars and detect explosive gravitational wave events. Open issues concern treatment of heteroscedastic measurement errors and understanding probability distributions characterizing astrophysical systems. The field of astrostatistics needs increased collaboration with statisticians in the design and analysis stages of research projects, and to jointly develop new statistical methodologies. Together, they will draw more astrophysical insights into astronomical populations and the cosmos itself.

[18]  arXiv:2005.13035 [pdf, other]
Title: Detection of exomoons in simulated light curves with a regularized convolutional neural network
Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Instrumentation and Methods for Astrophysics (astro-ph.IM); Solar and Stellar Astrophysics (astro-ph.SR)

Many moons have been detected around planets in our Solar System, but none has been detected unambiguously around any of the confirmed extrasolar planets. We test the feasibility of a supervised convolutional neural network to classify photometric transit light curves of planet-host stars and identify exomoon transits, while avoiding false positives caused by stellar variability or instrumental noise. Convolutional neural networks are known to have contributed to improving the accuracy of classification tasks. The network optimization is typically performed without studying the effect of noise on the training process. Here we design and optimize a 1D convolutional neural network to classify photometric transit light curves. We regularize the network by the total variation loss in order to remove unwanted variations in the data features. Using numerical experiments, we demonstrate the benefits of our network, which produces results comparable to or better than the standard network solutions. Most importantly, our network clearly outperforms a classical method used in exoplanet science to identify moon-like signals. Thus the proposed network is a promising approach for analyzing real transit light curves in the future.

[19]  arXiv:2005.13042 [pdf, other]
Title: Deep learning for Directional Dark Matter search
Comments: 5 pages, 6 figures. This is a proceedings paper from the ACAT2019 conference: this https URL
Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM)

We provide an algorithm for detection of possible dark matter particle interactions recorded within NEWSdm detector. The NEWSdm (Nuclear Emulsions for WIMP Search directional measure) is an underground Direct detection Dark Matter search experiment. The usage of recent developments in the nuclear emulsions allows probing new regions in the WIMP parameter space. The directional approach, which is the key feature of the NEWSdm experiment, gives the unique chance of overcoming the "neutrino floor". Deep Neural Networks were used for separation between potential DM signal and various classes of background. In this paper, we present the usage of deep 3D Convolutional Neural Networks to take into account the physical peculiarities of the datasets and report the achievement of the required $10^4$ background rejection power.

[20]  arXiv:2005.13059 [pdf, other]
Title: On the local and global properties of the gravitational spheres of influence
Comments: 11 pages, 5 figures
Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)

We revisit the concept of sphere of gravitational activity, to which we give both a geometrical and physical meaning. This study aims to refine this concept in a much broader context that could, for instance, be applied to exo-planetary problems (in a Galactic stellar disc-Star-Planets system) to define a first order "border" of a planetary system. The methods used in this paper rely on classical Celestial Mechanics and develop the equations of motion in the framework of the 3-body problem (e.g. Star-Planet-Satellite System). We start with the basic definition of planet's sphere of activity as the region of space in which it is feasible to assume a planet as the central body and the Sun as the perturbing body when computing perturbations of the satellite's motion. We then investigate the geometrical properties and physical meaning of the ratios of Solar accelerations (central and perturbing) and planetary accelerations (central and perturbing), and the boundaries they define. We clearly distinguish throughout the paper between the sphere of activity, the Chebotarev sphere (a particular case of the sphere of activity), Laplace sphere, and the Hill sphere. The last two are often wrongfully thought to be one and the same. Furthermore, taking a closer look and comparing the ratio of the star's accelerations (central/perturbing) to that of the planetary acceleration (central/perturbing) as a function of the planeto-centric distance, we have identified different dynamical regimes which are presented in the semi-analytical analysis.

[21]  arXiv:2005.13065 [pdf, other]
Title: On the measurement of handedness in Fermi Large Area Telescope data
Comments: 11 pages, 7 figures. Accepted for publication in ApJ
Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)

A handedness in the arrival directions of high-energy photons from outside our Galaxy can be related to the helicity of an intergalactic magnetic field. Previous estimates by arXiv:1310.4826 and arXiv:1412.3171 showed a hint of a signal present in the photons observed by the Fermi Large Area Telescope (LAT). An update on the measurement of handedness in Fermi-LAT data is presented using more than 10 years of observations. Simulations are performed to study the uncertainty of the measurements, taking into account the structure of the exposure caused by the energy-dependent instrument response and its observing profile, as well as the background from the interstellar medium. The simulations are required to accurately estimate the uncertainty and to show that previously the uncertainty was significantly underestimated. The apparent signal in the earlier analysis of {\em Fermi}-LAT data is rendered non-significant.

[22]  arXiv:2005.13077 [pdf, other]
Title: Magnetic Field Structure of Orion Source I
Comments: 71 pages, 57 figures, accepted for publication in The Astrophysical Journal
Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA)

We observed polarization of the SiO rotational transitions from Orion Source I (SrcI) to probe the magnetic field in bipolar outflows from this high mass protostar. Both 43 GHz $J$=1-0 and 86 GHz $J$=2-1 lines were mapped with $\sim$20 AU resolution, using the VLA and ALMA, respectively. The $^{28}$SiO transitions in the ground vibrational state are a mixture of thermal and maser emission. Comparison of the polarization position angles in the $J$=1-0 and $J$=2-1 transitions allows us to set an upper limit on possible Faraday rotation of $10^{4}$ radians m$^{-2}$, which would twist the $J$=2-1 position angles typically by less than 10 degrees. The smooth, systematic polarization structure in the outflow lobes suggests a well ordered magnetic field on scales of a few hundred AU. The uniformity of the polarization suggests a field strength of $\sim$30 milli-Gauss. It is strong enough to shape the bipolar outflow and possibly lead to sub-Keplerian rotation of gas at the base of the outflow. The strikingly high fractional linear polarizations of 80-90% in the $^{28}$SiO $v$=0 masers require anisotropic pumping. We measured circular polarizations of 60% toward the strongest maser feature in the $v$=0 $J$=1-0 peak. Anisotropic resonant scattering (ARS) is likely to be responsible for this circular polarization. We also present maps of the $^{29}$SiO $v$=0 $J$=2-1 maser and several other SiO transitions at higher vibrational levels and isotopologues.

[23]  arXiv:2005.13126 [pdf, other]
Title: The clustering of LRGs in the DECaLS DR8 footprint: distance constraints from baryon acoustic oscillations using photometric redshifts
Comments: 18 pages, 8 figures, DESI publication board APPROVED, submitted to ApJ
Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)

A photometric redshift sample of Luminous Red Galaxies (hereafter LRGs) obtained from The DECam Legacy Survey (DECaLS) is analysed to probe cosmic distances by exploiting the wedge approach of the two-point correlation function. Although the cosmological information is highly contaminated by the uncertainties existing in the photometric redshifts from the galaxy map, an angular diameter distance can be probed at the perpendicular configuration in which the measured correlation function is minimally contaminated. An ensemble of wedged correlation functions selected up to a given threshold based on having the least contamination was studied in the previous work (arXiv:1903.09651v2 [astro-ph.CO]) using simulations, and the extracted cosmological information was unbiased within this threshold. We apply the same methodology for analysing the LRG sample from DECaLS which will provide the optical imaging for targeting two-thirds of the DESI footprint and measure the angular diameter distances at $z=0.69$ and $z=0.87$ to be $D_{A}(0.697)=(1499 \pm 77\,\mathrm{Mpc})(r_{d}/r_{d,fid})$ and $D_{A}(0.874)=(1680 \pm 109\,\mathrm{Mpc})(r_{d}/r_{d,fid})$ with a fractional error of 5.14% and 6.48% respectively. We obtain a value of $H_{0}=67.59\pm5.52$ km/s/Mpc which supports the $H_0$ measured by all other BAO results and is consistent with $\Lambda$CDM model.

[24]  arXiv:2005.13157 [pdf, other]
Title: Disentangling the Cosmic Web Towards FRB 190608
Authors: Sunil Simha (1), Joseph N. Burchett (1), J. Xavier Prochaska (1 and 2), Jay S. Chittidi (3), Oskar Elek (1), Nicolas Tejos (4), Regina Jorgenson (3), Keith W. Bannister (5), Shivani Bhandari (5), Cherie K. Day (5,6), Adam T. Deller (6), Angus G. Forbes (1), Jean-Pierre Macquart (7), Stuart D. Ryder (8), Ryan M. Shannon (6) ((1) University of California Santa Cruz, Santa Cruz, USA, (2) Kavli Institute for the Physics and Mathematics of the Universe, Kashiwanoha, Japan, (3) Maria Mitchell Observatory, Nantucket, USA, (4) Instituto de Física, Pontificia Universidad Católica de Valparaíso, Casilla, Chile, (5) Australia Telescope National Facility, CSIRO Astronomy and Space Science, Australia, (6) Centre for Astrophysics and Supercomputing, Swinburne University of Technology, Hawthorn, Australia, (7) International Centre for Radio Astronomy Research, Curtin University, Bentley, Australia, (8) Department of Physics & Astronomy, Macquarie University, Australia)
Comments: 14 pages, 9 figures, 3 tables. The full version of Table 1 is available as a LaTeX file. Only the first 10 entries are present in the print version. Submitted to ApJ
Subjects: Astrophysics of Galaxies (astro-ph.GA)

FRB 190608 was detected by ASKAP and localized to a spiral galaxy at $z_{host}=0.11778$ in the SDSS footprint. The burst has a large dispersion measure ($DM_{FRB}=339.8$ $pc/cm^3$) compared to the expected cosmic average at its redshift. It also has a large rotation measure ($RM_{FRB}=353$ $rad/m^2$) and scattering timescale ($\tau=3.3$ $ms$ at $1.28$ $GHz$). Chittidi et al (2020) perform a detailed analysis of the ultraviolet and optical emission of the host galaxy and estimate the host DM contribution to be $137\pm 43$ $pc/cm^3$. This work complements theirs and reports the analysis of the optical data of galaxies in the foreground of FRB 190608 to explore their contributions to the FRB signal. Together, the two manuscripts delineate an observationally driven, end-to-end study of matter distribution along an FRB sightline; the first study of its kind. Combining KCWI observations and public SDSS data, we estimate the expected cosmic dispersion measure $DM_{cosmic}$ along the sightline to FRB 190608. We first estimate the contribution of hot, ionized gas in intervening virialized halos ($DM_{halos} \approx 7-28$ $pc/cm^3$). Then, using the Monte Carlo Physarum Machine (MCPM) methodology, we produce a 3D map of ionized gas in cosmic web filaments and compute the DM contribution from matter outside halos ($DM_{IGM} \approx 91-126$ $pc/cm^3$). This implies a greater fraction of ionized gas along this sightline is extant outside virialized halos. We also investigate whether the intervening halos can account for the large FRB rotation measure and pulse width and conclude that it is implausible. Both the pulse broadening and the large Faraday rotation likely arise from the progenitor environment or the host galaxy.

[25]  arXiv:2005.13158 [pdf, other]
Title: Dissecting the Local Environment of FRB 190608 in the Spiral Arm of its Host Galaxy
Authors: Jay S. Chittidi (1), Sunil Simha (2), Alexandra Mannings (2), J. Xavier Prochaska (2 and 3), Marc Rafelski (4 and 5), Marcel Neeleman (6), Jean-Pierre Macquart (7), Nicolas Tejos (8), Regina A. Jorgenson (1), Stuart D. Ryder (9), Cherie K. Day (10 and 11), Lachlan Marnoch (9), Shivani Bhandari (11), Adam T. Deller (10), Hao Qiu (12 and 11), Keith W. Bannister (11), Ryan M. Shannon (10), Kasper E. Heintz (13) ((1) Maria Mitchell Observatory, Nantucket, USA, (2) University of California - Santa Cruz, Santa Cruz, USA, (3) Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU), Kashiwanoha, Japan, (4) Space Telescope Science Institute, Baltimore, USA, (5) Department of Physics & Astronomy, Johns Hopkins University, Baltimore, USA, (6) Max-Planck-Institut für Astronomie, Königstuhl, Heidelberg, Germany, (7) International Centre for Radio Astronomy Research, Curtin University, Bentley, Australia, (8) Instituto de Física, Pontificia Universidad Católica de Valparaíso, Casilla, Chile, (9) Department of Physics & Astronomy, Macquarie University, Australia, (10) Centre for Astrophysics and Supercomputing, Swinburne University of Technology, Hawthorn, Australia, (11) Australia Telescope National Facility, CSIRO Astronomy and Space Science, Australia, (12) Sydney Institute for Astronomy, School of Physics, Australia, (13) Centre for Astrophysics and Cosmology, Science Institute, University of Iceland, Reykjavík, Iceland)
Comments: 16 pages, 8 figure files, 7 figures in paper, 3 tables. Submitted to ApJ
Subjects: Astrophysics of Galaxies (astro-ph.GA)

We present a high-resolution analysis of the host galaxy of fast radio burst FRB 190608, an SBc galaxy at $z=0.11778$ (hereafter HG 190608), to dissect its local environment and its contributions to the FRB properties. Our Hubble Space Telescope WFC3/UVIS image reveals that the sub-arcsecond localization of FRB 190608 is coincident with a knot of star-formation ($\Sigma_{SFR} = 1.2 \times 10^{-2}~ M_{\odot} \, kpc^{-2}$) in one of the prominent spiral arms of HG 190608. This is confirmed by H$\beta$ emission present in our Keck/KCWI integral field spectrum of the galaxy with a surface brightness of $\mu_{H\beta} = (3.35\pm0.18)\times10^{-17}\;erg\;s^{-1}\;cm^{-2}\;arcsec^{-2}$. We infer an extinction-corrected H$\alpha$ surface brightness and compute a dispersion measure from the interstellar medium of HG 190608 of ${DM}_{Host,ISM} = 82 \pm 35~ pc \, cm^{-3}$. The galaxy rotates with a circular velocity $v_{circ} = 141 \pm 8~ km \, s^{-1}$ at an inclination $i_{gas} = 37 \pm 3^\circ$, giving a dynamical mass $M_{halo}^{dyn} \approx 10^{11.96 \pm 0.08}~ M_{\odot}$. A surface photometric analysis of the galaxy using FORS2 imaging suggests a stellar disk inclination of $i_{stellar} = 26 \pm 3^\circ$. The dynamical mass estimate implies a halo contribution to the dispersion measure of ${DM}_{Host,Halo} = 55 \pm 25\; pc \, cm^{-3}$ subject to assumptions on the density profile and fraction of baryons retained. The relatively high temporal broadening ($\tau = 3.3 \pm 0.2 \; ms$ at 1.28 GHz) and rotation measure ($ RM = 353 \pm 2\; rad \; m^{-2}$) (Day et al. 2020) of FRB 190608 may be attributable to both turbulent gas within the spiral arm and gas local to the FRB progenitor. In contrast to previous high-resolution studies of FRB progenitor environments, we find no evidence for disturbed morphology, emission, nor kinematics for FRB 190608.

[26]  arXiv:2005.13159 [pdf, other]
Title: A search for supernova-like optical counterparts to ASKAP-localised Fast Radio Bursts
Comments: 7 pages, 3 figures. Accepted to Astronomy & Astrophysics as a Letter
Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)

Fast radio bursts (FRBs) are millisecond-scale radio pulses, which originate in distant galaxies and are produced by unknown sources. The mystery remains partially because of the typical difficulty in localising FRBs to host galaxies. Accurate localisations delivered by the Commensal Real-time ASKAP Fast Transients (CRAFT) survey now provide an opportunity to study the host galaxies and potential transient counterparts of FRBs at a large range of wavelengths. In this work, we investigate whether the first three FRBs accurately localised by CRAFT have supernova-like transient counterparts. We obtained two sets of imaging epochs with the Very Large Telescope for three host galaxies, one soon after the burst detection and one several months later. After subtracting these images no optical counterparts were identified in the associated FRB host galaxies, so we instead place limits on the brightness of any potential optical transients. A Monte Carlo approach, in which supernova light curves were modelled and their base properties randomised, was used to estimate the probability of a supernova associated with each FRB going undetected. We conclude that Type Ia and IIn supernovae are unlikely to accompany every apparently non-repeating FRB.

[27]  arXiv:2005.13160 [pdf, other]
Title: The host galaxies and progenitors of Fast Radio Bursts localized with the Australian Square Kilometre Array Pathfinder
Comments: 15 pages, 5 figures, 5 tables. Accepted for publication in ApJL
Subjects: Astrophysics of Galaxies (astro-ph.GA); High Energy Astrophysical Phenomena (astro-ph.HE)

The Australian SKA Pathfinder (ASKAP) telescope has started to localize Fast Radio Bursts (FRBs) to arcsecond accuracy from the detection of a single pulse, allowing their host galaxies to be reliably identified. We discuss the global properties of the host galaxies of the first four FRBs localized by ASKAP, which lie in the redshift range $0.11<z<0.48$. All four are massive galaxies (log( $M_{*}/ M_{\odot}$) $\sim 9.4 -10.4$) with modest star-formation rates of up to $2M_{\odot}$yr$^{-1}$ -- very different to the host galaxy of the first repeating FRB 121102, which is a dwarf galaxy with a high specific star-formation rate. The FRBs localized by ASKAP typically lie in the outskirts of their host galaxies, which appears to rule out FRB progenitor models that invoke active galactic nuclei (AGN) or free-floating cosmic strings. The stellar population seen in these host galaxies also disfavors models in which all FRBs arise from young magnetars produced by superluminous supernovae (SLSNe), as proposed for the progenitor of FRB 121102. A range of other progenitor models (including compact-object mergers and magnetars arising from normal core-collapse supernovae) remain plausible.

[28]  arXiv:2005.13161 [pdf, other]
Title: A census of baryons in the Universe from localized fast radio bursts
Comments: Published online in Nature 27 May, 2020
Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Astrophysics of Galaxies (astro-ph.GA); High Energy Astrophysical Phenomena (astro-ph.HE)

More than three quarters of the baryonic content of the Universe resides in a highly diffuse state that is difficult to observe, with only a small fraction directly observed in galaxies and galaxy clusters. Censuses of the nearby Universe have used absorption line spectroscopy to observe these invisible baryons, but these measurements rely on large and uncertain corrections and are insensitive to the majority of the volume, and likely mass. Specifically, quasar spectroscopy is sensitive either to only the very trace amounts of Hydrogen that exists in the atomic state, or highly ionized and enriched gas in denser regions near galaxies. Sunyaev-Zel'dovich analyses provide evidence of some of the gas in filamentary structures and studies of X-ray emission are most sensitive to gas near galaxy clusters. Here we report the direct measurement of the baryon content of the Universe using the dispersion of a sample of localized fast radio bursts (FRBs), thus utilizing an effect that measures the electron column density along each sight line and accounts for every ionised baryon. We augment the sample of published arcsecond-localized FRBs with a further four new localizations to host galaxies which have measured redshifts of 0.291, 0.118, 0.378 and 0.522, completing a sample sufficiently large to account for dispersion variations along the line of sight and in the host galaxy environment to derive a cosmic baryon density of $\Omega_{b} = 0.051_{-0.025}^{+0.021} \, h_{70}^{-1}$ (95% confidence). This independent measurement is consistent with Cosmic Microwave Background and Big Bang Nucleosynthesis values.

[29]  arXiv:2005.13162 [pdf, other]
Title: High time resolution and polarisation properties of ASKAP-localised fast radio bursts
Comments: 18 pages, 4 figures, 5 tables, submitted to MNRAS
Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)

Combining high time and frequency resolution full-polarisation spectra of Fast Radio Bursts (FRBs) with knowledge of their host galaxy properties provides an opportunity to study both the emission mechanism generating them and the impact of their propagation through their local environment, host galaxy, and the intergalactic medium. The Australian Square Kilometre Array Pathfinder (ASKAP) telescope has provided the first ensemble of bursts with this information. In this paper, we present the high time and spectral resolution, full polarisation observations of five localised FRBs to complement the results published for the previously studied ASKAP FRB~181112. We find that every FRB is highly polarised, with polarisation fractions ranging from 80 -- 100\%, and that they are generally dominated by linear polarisation. While some FRBs in our sample exhibit properties associated with an emerging archetype (i.e., repeating or apparently non-repeating), others exhibit characteristic features of both, implying the existence of a continuum of FRB properties. When examined at high time resolution, we find that all FRBs in our sample have evidence for multiple sub-components and for scattering at a level greater than expected from the Milky Way. We find no correlation between the diverse range of FRB properties (e.g., scattering time, intrinsic width, and rotation measure) and any global property of their host galaxy. The most heavily scattered bursts reside in the outskirts of their host galaxies, suggesting that the source-local environment rather than the host interstellar medium is likely the dominant origin of the scattering in our sample.

[30]  arXiv:2005.13177 [pdf, other]
Title: The fates of massive stars: exploring uncertainties in stellar evolution with METISSE
Comments: Submitted to MNRAS
Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Instrumentation and Methods for Astrophysics (astro-ph.IM)

In the era of advanced electromagnetic and gravitational wave detectors, it has become increasingly important to effectively combine and study the impact of stellar evolution on binaries and dynamical systems of stars. Systematic studies dedicated to exploring uncertain parameters in stellar evolution are required to account for the recent observations of the stellar populations. We present a new approach to the commonly used Single-Star Evolution (SSE) fitting formulae, one that is more adaptable: Method of Interpolation for Single Star Evolution (METISSE). It makes use of interpolation between sets of pre-computed stellar tracks to approximate evolution parameters for a population of stars. We have used METISSE with detailed stellar tracks computed by the Modules for Experiments in Stellar Astrophysics (MESA), Bonn Evolutionary Code (BEC) and Cambridge STARS code. METISSE better reproduces stellar tracks computed using the STARS code compared to SSE, and is on average three times faster. Using stellar tracks computed with MESA and BEC, we apply METISSE to explore the differences in the remnant masses, the maximum radial expansion, and the main sequence lifetime of massive stars. We find that different physical ingredients used in the evolution of stars, such as the treatment of radiation dominated envelopes, can impact their evolutionary outcome. For stars in the mass range 9-100 M$_\odot$, the predictions of remnant masses can vary by up to 20 M$_\odot$, while the maximum radial expansion achieved by a star can differ by an order of magnitude between different stellar models.

[31]  arXiv:2005.13190 [pdf, other]
Title: Atmospheric Escape From TOI-700 d: Venus vs. Earth Analogs
Comments: 8 pages, 3 figures, and 1 table
Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR); Space Physics (physics.space-ph)

The recent discovery of an Earth-sized planet (TOI-700 d) in the habitable zone of an early-type M-dwarf by the Transiting Exoplanet Survey Satellite constitutes an important advance. In this Letter, we assess the feasibility of this planet to retain an atmosphere - one of the chief ingredients for surface habitability - over long timescales by employing state-of-the-art magnetohydrodynamic models to simulate the stellar wind and the associated rates of atmospheric ion escape. We take two major factors into consideration, namely, the planetary atmospheric composition and magnetic field. In all cases, we determine that the atmospheric ion escape rates are potentially a few orders of magnitude higher than the inner Solar system planets, but TOI-700 d is nevertheless capable of retaining a $1$-bar atmosphere over gigayear timescales for certain regions of the parameter space. We also discuss the prospects for detecting radio emission of the planet (thereby constraining its magnetic field) and discerning the presence of an atmosphere.

[32]  arXiv:2005.13200 [pdf]
Title: On The Geological Time Evolution of Volcanism in the Inner Solar System
Comments: 30 Pages and 15 Figures
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)

We have studied the geological time evolution of volcanism in Earth and other inner solar system planetary bodies (Mercury, Moon, Mars and Venus) in both geophysical and biophysical perspective. The record of Large Igneous Provinces in Earth and other planetary objects suggest the existence of increasing, decreasing and cessation phases of major volcanic activity over geological time scales. We have extended the existing scale of measuring intensity of volcanic eruptions based on Earth based observations to accommodate intense and extreme volcanic activity. The mass of a rocky planetary object is found to be related to the magnitude of the internal heat, occurrences of Large Igneous Provinces and the duration of major volcanic activity from relevant data available for the inner solar system. The internal heat magnitude may also decide the intensity of volcanism in these planetary objects. The time evolution of volcanism in Earth and Mars has probably influenced the origin of life and biological evolution in these planets.

[33]  arXiv:2005.13287 [pdf, other]
Title: Analysing AIA Flare Observations using Convolutional Neural Networks
Comments: 9 pages, 4 figures. To be published in Frontiers in Astronomy and Space Science as part of the Machine Learning in Heliophysics research topic
Subjects: Solar and Stellar Astrophysics (astro-ph.SR)

In order to efficiently analyse the vast amount of data generated by solar space missions and ground-base instruments, modern machine learning techniques such as decision trees, support vector machines (SVMs) and neural networks can be very useful. In this paper we present initial results from using a convolutional neural network (CNN) to analyse observations from the Atmospheric Imaging Assembly (AIA) in the 1600A wavelength. The data is pre-processed to locate flaring regions where flare ribbons are visible in the observations. The CNN is created and trained to automatically analyse the shape and position of the flare ribbons, by identifying whether each image belongs into one of four classes: two-ribbon flare, compact/circular ribbon flare, limb flare or quiet Sun, with the final class acting as a control for any data included in the training or test sets where flaring regions are not present. The network created can classify flare ribbon observations into any of the four classes with a final accuracy of 94%. Initial results show that most of the images are correctly classified with the compact flare class being the only class where accuracy drops below 90% ad some observations are wrongly classified as belonging to the limb class.

[34]  arXiv:2005.13310 [pdf, other]
Title: Rotating self-gravitating Bose-Einstein condensates with a crust: a minimal model for pulsar glitches
Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); Astrophysics of Galaxies (astro-ph.GA); Quantum Gases (cond-mat.quant-gas); Fluid Dynamics (physics.flu-dyn)

We develop a minimal model for \textit{pulsar glitches} by introducing a solid-crust potential in the three-dimensional (3D) Gross-Pitaevskii-Poisson equation (GPPE), which we have used earlier to study gravitationally bound Bose-Einstein Condensates (BECs), i.e., bosonic stars. In the absence of the crust potential, we show that, if we rotate such a bosonic star, it is threaded by vortices. We then show, via extensive direct numerical simulations (DNSs), that the interaction of these vortices with the crust potential yields (a) stick-slip dynamics and (b) dynamical glitches. We demonstrate that, if enough momentum is transferred to the crust from the bosonic star, then the vortices are expelled from the star and the crust's angular momentum $J_c$ exhibits features that can be interpreted naturally as glitches. From the time series of $J_c$, we compute the cumulative probability distribution functions (CPDFs) of event sizes, event durations, and waiting times. We show that these CPDFs have signatures of self-organized criticality (SOC), which have been seen in observations on pulsar glitches.

[35]  arXiv:2005.13333 [pdf, other]
Title: Supervised convolutional neural networks for classification of flaring and nonflaring active regions using line-of-sight magnetograms
Comments: 16 pages, 13 figures, accepted for publication in ApJ
Subjects: Solar and Stellar Astrophysics (astro-ph.SR)

Solar flares are explosions in the solar atmosphere that release intense bursts of short-wavelength radiation and are capable of producing severe space-weather consequences. Flares release free energy built up in coronal fields, which are rooted in active regions (ARs) on the photosphere, via magnetic reconnection. The exact processes that lead to reconnection are not fully known and therefore reliable forecasting of flares is challenging. Recently, photospheric magnetic-field data has been extensively analysed using machine learning (ML) and these studies suggest that flare-forecasting accuracy does not strongly depend on how long in advance flares are predicted (Bobra & Couvidat 2015; Raboonik et al. 2017; Huang et al. 2018). Here, we use ML to understand the evolution of AR magnetic fields before and after flares. We explicitly train convolutional neural networks (CNNs) to classify SDO/HMI line-of-sight magnetograms into ARs producing at least one M- or X-class flare or as nonflaring. We find that flaring ARs remain in flare-productive states -- marked by recall >60% with a peak of ~ 80% -- days before and after flares. We use occlusion maps and statistical analysis to show that the CNN pays attention to regions between the opposite polarities from ARs and the CNN output is dominantly decided by the total unsigned line-of-sight flux of ARs. Using synthetic bipole magnetograms, we find spurious dependencies of the CNN output on magnetogram dimensions for a given bipole size. Our results suggest that it is important to use CNN designs that eliminate such artifacts in CNN applications for processing magnetograms and, in general, solar image data.

[36]  arXiv:2005.13346 [pdf, ps, other]
Title: ALMA 26 arcmin$^2$ survey of GOODS-S at one-millimeter (ASAGAO): millimeter properties of stellar mass selected galaxies
Comments: Accepted for publication in PASJ. A version with a high resolution figure and ALMA fits files are available from this https URL
Subjects: Astrophysics of Galaxies (astro-ph.GA)

We make use of the ASAGAO, deep 1.2 mm continuum observations of a 26 arcmin$^2$ region in the GOODS-South field obtained with ALMA, to probe dust-enshrouded star formation in $K$-band selected (i.e., stellar mass selected) galaxies, which are drawn from the ZFOURGE catalog. Based on the ASAGAO combined map, which was created by combining ASAGAO and ALMA archival data in the GOODS-South field, we find that 24 ZFOURGE sources have 1.2 mm counterparts with a signal-to-noise ratio $>$ 4.5 (1$\sigma\simeq$ 30 - 70 $\mu$Jy beam$^{-1}$ at 1.2 mm). Their median redshift is estimated to be $z_\mathrm{median}=$ 2.38 $\pm$ 0.14. They generally follow the tight relationship of the stellar mass versus star formation rate (i.e., the main sequence of star-forming galaxies). ALMA-detected ZFOURGE sources exhibit systematically larger infrared (IR) excess (IRX $\equiv L_\mathrm{IR}/L_\mathrm{UV}$) compared to ZFOURGE galaxies without ALMA detections even though they have similar redshifts, stellar masses, and star formation rates. This implies the consensus stellar-mass versus IRX relation, which is known to be tight among rest-frame-UV-selected galaxies, can not fully predict the ALMA detectability of stellar-mass-selected galaxies. We find that ALMA-detected ZFOURGE sources are the main contributors to the cosmic IR star formation rate density at $z$ = 2 - 3.

[37]  arXiv:2005.13360 [pdf, other]
Title: Say hello to Algol D and Algol E
Authors: L. Jetsu
Comments: 5 pages, 3 figures, 4 Tables
Subjects: Solar and Stellar Astrophysics (astro-ph.SR)

Regular changes in the observed (O) and the computed (C) epochs of binary eclipses may reveal the presence of a third or a fourth body. One recent study showed that the probability for detecting a fourth body from the O-C data is only 0.00005. We apply the new Discrete Chi-square Method (DCM) to the O-C data of Algol, and detect three wide orbit stars having orbital periods 1.9 years (Algol C), 18.6 years (Algol D) and 52.5 years (Algol E). Since our estimate for the period of Algol C agrees perfectly with the previous estimates, the signals of Algol D and Algol E are certainly real. The orbits of all these three wide orbit stars are most probably co-planar, because no changes have been observed in eclipses of Algol.

[38]  arXiv:2005.13370 [pdf, other]
Title: A Gemini/GMOS study of the bright elliptical galaxy NGC 3613 and its globular cluster system
Journal-ref: volume = 492, year= 2020, pages = 4313-4324
Subjects: Astrophysics of Galaxies (astro-ph.GA)

We present the first photometric study of the globular cluster system (GCS) of the E galaxy NGC 3613 (Mv = -21.5, d = 30.1 Mpc), as well as the surface photometry of the host galaxy, based on Gemini/GMOS images. Being considered the central galaxy of a group, NGC 3613 inhabits a low-density environment although its intrinsic brightness is similar to the expected one for galaxies in the centre of clusters. The following characteristics are obtained for this GCS. The colour distribution is bimodal, with metal-poor globular clusters (GCs) getting slightly bluer with increasing radius. The radial and azimuthal projected distributions show that metal-rich GCs are more concentrated towards the host galaxy and trace its light distribution very precisely, while metal-poor GCs present a more extended and uniform distribution. The GC luminosity function helps validate the adopted distance. The estimated total GC population of Ntot= 2075 +/- 130 leads to a specific frequency Sn=5.2 +/- 0.7, a value within the expected range for GCSs with host galaxies of similar luminosity. The surface photometry of NGC 3613 reveals a three-component profile and a noticeable substructure. Finally, a small sample of ultra-compact dwarf (UCD) candidates are identified in the surroundings of the host galaxy.

[39]  arXiv:2005.13373 [pdf, other]
Title: Deep Learning Assisted Data Inspection for Radio Astronomy
Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM)

Modern radio telescopes combine thousands of receivers, long-distance networks, large-scale compute hardware, and intricate software. Due to this complexity, failures occur relatively frequently. In this work we propose novel use of unsupervised deep learning to diagnose system health for modern radio telescopes. The model is a convolutional Variational Autoencoder (VAE) that enables the projection of the high dimensional time-frequency data to a low-dimensional prescriptive space. Using this projection, telescope operators are able to visually inspect failures thereby maintaining system health. We have trained and evaluated the performance of the VAE quantitatively in controlled experiments on simulated data from HERA. Moreover, we present a qualitative assessment of the the model trained and tested on real LOFAR data. Through the use of a naive SVM classifier on the projected synthesised data, we show that there is a trade-off between the dimensionality of the projection and the number of compounded features in a given spectrogram. The VAE and SVM combination scores between 65% and 90% accuracy depending on the number of features in a given input. Finally, we show the prototype system-health-diagnostic web framework that integrates the evaluated model. The system is currently undergoing testing at the ASTRON observatory.

[40]  arXiv:2005.13386 [pdf, other]
Title: Unsigned magnetic flux as a proxy for radial-velocity variations in Sun-like stars
Comments: 25 pages, 11 figures, 3 tables, submitted to ApJ
Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Earth and Planetary Astrophysics (astro-ph.EP)

We estimate disc-averaged RV variations of the Sun over the last magnetic cycle, from the single Fe I line observed by SDO/HMI, using a physical model for rotationally modulated magnetic activity that was previously validated against HARPS-N solar observations. We estimate the disc-averaged, unsigned magnetic flux and show that a simple linear fit to it reduces the RMS of RV variations by 62%, i.e. a factor of 2.6. We additionally apply the FF' method, which predicts RV variations based on a star's photometric variations. At cycle maximum, we find that additional physical processes must be at play beyond suppression of convective blueshift and velocity imablances resulting from brightness inhomogeneities, in agreement with recent studies of solar RV variations. By modelling RV variations over the magnetic cycle using a linear fit to the unsigned magnetic flux, we recover injected planets at an orbital period of about 300 days with RV semi-amplitudes down to 0.3 m/s. To reach semi-amplitudes of 0.1 m/s, we will need to identify and model additional physical phenomena that are not well traced by the unsigned magnetic flux or FF'. The unsigned magnetic flux is an excellent proxy for rotationally modulated, activity-induced RV variations, and could become a key tool in confirming and characterising Earth analogs orbiting Sun-like stars. The present study motivates ongoing and future efforts to develop observation and analysis techniques to measure the unsigned magnetic flux at high precision in slowly rotating, relatively inactive stars like the Sun.

[41]  arXiv:2005.13401 [pdf, other]
Title: Star cluster formation and cloud dispersal by radiative feedback: dependence on metallicity and compactness
Comments: 17 pages, 13 figures, submitted to MNRAS
Subjects: Astrophysics of Galaxies (astro-ph.GA); Solar and Stellar Astrophysics (astro-ph.SR)

We study star cluster formation in various environments with different metallicities and column densities by performing a suite of three-dimensional radiation hydrodynamics simulations. We find that the photoionization feedback from massive stars controls the star formation efficiency (SFE) in a star-forming cloud, and its impact sensitively depends on the gas metallicity $Z$ and initial cloud surface density $\Sigma$. At $Z=1~Z_{\odot}$, for instance, the SFE increases from 0.02 to 0.3 with $\Sigma$ from $10$ to $300~{\rm M_{\odot} {\rm pc^{-2}}}$. In low-metallicity cases $10^{-2}- 10^{-1} Z_{\odot}$, star clusters form from atomic warm gases because the molecule formation time is not short enough with respect to the cooling or dynamical time. In addition, the whole cloud is disrupted more easily by expanding HII bubbles which have higher temperature owing to less efficient cooling. With smaller dust attenuation, the ionizing radiation feedback from nearby massive stars is stronger and terminate star formation in dense clumps. These effects result in inefficient star formation in low-metallicity environments: the SFE is reduced by a factor of $\sim 0.3$ for the cases with $Z=10^{-2}~Z_{\odot}$ regardless of $\Sigma$. Newborn star clusters are also gravitationally less bound. We further develop a new semi-analytical model that can reproduce the simulation results well, particularly the observed dependencies of the SFEs on the cloud surface densities and metallicities.

[42]  arXiv:2005.13441 [pdf, other]
Title: On the cosmic-ray energy scale of the LOFAR radio telescope
Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); Instrumentation and Methods for Astrophysics (astro-ph.IM)

Cosmic rays are routinely measured at LOFAR, both with a dense array of antennas and an array of plastic scintillators. We compare the reconstruction of cosmic-ray energy using radio and particle techniques and show that they are in good agreement. We also present the radiation energy of air showers measured at LOFAR. This value scales quadratically with the electromagnetic energy in an air shower, which can in turn be related to the energy of the primary particle. Once the local magnetic field is accounted for, the radiation energy allows for a direct comparison between the LOFAR energy scale and that of the Pierre Auger Observatory, which are shown to be in agreement. This technique demonstrates the potential to cross-calibrate the energy scales of different experiments using radiation energy.

[43]  arXiv:2005.13446 [pdf, ps, other]
Title: PTF1J2224+17: a short-period, high-field polar
Comments: AN, in press (7 pages, 6 figures)
Subjects: Solar and Stellar Astrophysics (astro-ph.SR); High Energy Astrophysical Phenomena (astro-ph.HE)

We present time-resolved photometry of the cataclysmic variable (CV) PTF1J2224+17 obtained during 4 nights in October 2018 and January 2019 from Inastars observatory. The object is variable on a period of 103.82 min. Archival Catalina Real-Time Transient Survey (CRTS), PTF, and ZTF-data show frequent changes between high and low states. Based on its photometric properties and the cyclotron humps in the identification spectrum the object is certainly classified as an AM Herculis star (or polar) with a likely magnetic field strength of B ~ 65 MG. Its accretion duty cycle was estimated from nine years of photometric monitoring to be about 35 %.

[44]  arXiv:2005.13454 [pdf, other]
Title: AlFoCS + Fornax3D: resolved star formation in the Fornax cluster with ALMA and MUSE
Comments: Accepted for publication in MNRAS. 18 pages, 7 figures, plus 2 appendices
Subjects: Astrophysics of Galaxies (astro-ph.GA)

We combine data from ALMA and MUSE to study the resolved (~300 pc scale) star formation relation (star formation rate vs. molecular gas surface density) in cluster galaxies. Our sample consists of 9 Fornax cluster galaxies, including spirals, ellipticals, and dwarfs, covering a stellar mass range of ~10^8.8 - 10^11 M_Sun. CO(1-0) and extinction corrected Halpha were used as tracers for the molecular gas mass and star formation rate, respectively. We compare our results with Kennicutt (1998) and Bigiel et al. (2008). Furthermore, we create depletion time maps to reveal small-scale variations in individual galaxies. We explore these further in FCC290, using the 'uncertainty principle for star formation' (Kruijssen & Longmore, 2014a) to estimate molecular cloud lifetimes, which we find to be short (<10 Myr) in this galaxy. Galaxy-averaged depletion times are compared with other parameters such as stellar mass and cluster-centric distance. We find that the star formation relation in the Fornax cluster is close to those from Kennicutt (1998) and Bigiel et al. (2008}), but overlaps mostly with the shortest depletion times predicted by Bigiel et al. (2008). This slight decrease in depletion time is mostly driven by dwarf galaxies with disturbed molecular gas reservoirs close to the virial radius. In FCC90, a dwarf galaxy with a molecular gas tail, we find that depletion times are a factor >~10 higher in its tail than in its stellar body.

[45]  arXiv:2005.13467 [pdf, other]
Title: The Diffuse Light Envelope of Luminous Red Galaxies
Subjects: Astrophysics of Galaxies (astro-ph.GA)

We use a stacking method to study the radial light profiles of luminous red galaxies (LRGs) at redshift $\sim 0.62$ and $\sim 0.25$, out to a radial range of 200 kpc. We do not find noticeable evolution of the profiles at the two redshifts. The LRG profiles appear to be well approximated by a single Sersic profile, although some excess light can be seen outside 60 kpc. We quantify the excess light by measuring the integrated flux and find that the excess is about 10\% -- a non-dominant but still nonnegligible component.

[46]  arXiv:2005.13508 [pdf, ps, other]
Title: Inertial oscillation modes of an inclined dipolar magnetosphere as a source of band-limited noise in X-ray pulsars
Comments: accepted to MNRAS; 6 pages, 5 figures
Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)

Magnetic fields of strongly magnetized stars can trap conducting matter due to frozen-in condition. In the force-free regime, the motion of the matter along the field lines may be considered in the "bead on a wire" approximation. Such a motion, if gravity and centrifugal forces are taken into account, has equilibrium points, some of which are stable. In most cases, stability is possible in about several per cent of the possible locations. Corresponding oscillation frequencies span the range from zero to $\sqrt{3}$ of the spin frequency. We suggest that this variability mode may be excited in some X-ray pulsars during the outbursts and create the peaked broad-band noise component near the break frequency in the power density spectrum, as well as produce some of the quasi-periodic oscillation features in this frequency range. Existence of this variability does not require any changes in mass accretion rate and involves only a small amount of matter infiltrating from the disc and magnetic flow due to interchange instabilities.

Cross-lists for Thu, 28 May 20

[47]  arXiv:2005.12304 (cross-list from hep-ph) [pdf, other]
Title: Neutrino charge constraints from scattering to the weak gravity conjecture to neutron stars
Comments: 8 pages
Subjects: High Energy Physics - Phenomenology (hep-ph); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics - Experiment (hep-ex); High Energy Physics - Theory (hep-th)

In various extensions of the Standard Model of particle physics, and intriguingly even in the three-generation Standard Model without neutrino masses, neutrinos are allowed to have very tiny electric charges. We revisit the emergence of such charges and constraints on them, adding to the repertoire of limits that exist in literature, including new indirect limits on the charges of the muon and tau neutrinos respectively. We also point out the flavor-universal bounds on neutrino charges, motivated by the weak gravity conjecture and based on the observation of neutron stars with very large magnetic fields. The latter set of limits are relatively model independent, relying only on the hypothesis that gravity must be the weakest force and that any charged neutrino must have a coupling to the photon. The weak gravity conjecture gives a lower bound on the possible neutrino charge. Astrophysical observations of Magnetars meanwhile give an upper bound, comparable to recent limits derived from the reactor neutrinos, considering elastic neutrino-electron scattering, and experiments constraining neutrino magnetic moments.

[48]  arXiv:2005.12384 (cross-list from gr-qc) [pdf, other]
Title: The radial acceleration relation and its emergent nature
Comments: 2 pages, 1 figure. To appear in the Proceedings IAU Symposium No. 359, 2020. Galaxy evolution and feedback across different environments (Galfeed)
Subjects: General Relativity and Quantum Cosmology (gr-qc); Astrophysics of Galaxies (astro-ph.GA)

We review some of our recent results about the Radial Acceleration Relation (RAR) and its interpretation as either a fundamental or an emergent law. The former interpretation is in agreement with a class of modified gravity theories that dismiss the need for dark matter in galaxies (MOND in particular). Our most recent analysis, which includes refinements on the priors and the Bayesian test for compatibility between the posteriors, confirms that the hypothesis of a fundamental RAR is rejected at more than 5$\sigma$ from the very same data that was used to infer the RAR.

[49]  arXiv:2005.12923 (cross-list from hep-ph) [pdf, other]
Title: General relativistic non-ideal fluid equations for dark matter from a truncated cumulant expansion
Comments: 10 pages, 1 figure
Subjects: High Energy Physics - Phenomenology (hep-ph); Cosmology and Nongalactic Astrophysics (astro-ph.CO)

A new truncation scheme based on the cumulant expansion of the one-particle phase-space distribution function for dark matter particles is developed. Extending the method of moments in relativistic kinetic theory, we derive evolution equations which supplement the covariant conservation of the energy-momentum tensor and particle number current. Truncating the cumulant expansion we obtain a closed, covariant and hyperbolic system of equations which can be used to model the evolution of a general relativistic non-ideal fluid. As a working example we consider a Friedmann-Lema\^itre-Robertson-Walker cosmology with dynamic pressure and solve for the time evolution of the effective equation of state parameter.

[50]  arXiv:2005.13068 (cross-list from hep-ph) [pdf, other]
Title: Supernovae neutrino detection via coherent scattering off silicon nuclei
Comments: 7 pages, 6 figures
Subjects: High Energy Physics - Phenomenology (hep-ph); High Energy Astrophysical Phenomena (astro-ph.HE)

Low-energy neutrinos are clean messengers from supernovae explosions and probably carry unique insights into the process of stellar evolution. We estimate the expected number of events considering coherent elastic scattering of neutrinos off silicon nuclei, as would happen in Charge Coupled Devices (CCD) detectors. The number of expected events, integrated over a window of about 18 s, is $\sim$ 4 if we assume 10 kg of silicon and a supernovae 1 kpc away. For a a distance similar to the red supergiant Betelgeuse, the number of expected events increases to $\sim$ 30 - 120, depending on the supernovae model. We argue that silicon detectors can be effective for supernovae neutrinos, and might possibly distinguish between models for certain target masses and distances.

[51]  arXiv:2005.13136 (cross-list from hep-ph) [pdf, ps, other]
Title: Modified MIT Bag Models: Thermodynamical consistency, stability windows and symmetry group
Comments: 12 pages, 9 figures
Subjects: High Energy Physics - Phenomenology (hep-ph); High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)

In this work we study different variations of the MIT bag model. We start with the so called non-ideal bag model and discuss it in detail. Then we implement a vector interaction in the MIT bag model that simulates a meson exchange interaction and fix the quark-meson coupling constants via symmetry group theory. At the end we propose an original model, inspired by the Boguta-Bodmer models, which allows us to control the repulsion interaction at high densities. For each version of the model we obtain a stability window as predicted by the Bodmer-Witten conjecture and discuss its thermodynamical consistency.

[52]  arXiv:2005.13221 (cross-list from physics.pop-ph) [pdf, ps, other]
Title: Qualitative classification of extraterrestrial civilizations
Comments: accepted in A&A; 7 pages, 1 figure
Subjects: Popular Physics (physics.pop-ph); Earth and Planetary Astrophysics (astro-ph.EP)

Abridged: The interest towards searches for extraterrestrial civilizations (ETCs) was boosted by the discovery of thousands of exoplanets. We turn to the classification of ETCs for new considerations that may help to design better strategies for ETCs searches. We take a basic taxonomic approach to ETCs and investigate the implications of the new classification on ETCs observational patterns. We use as a counter-example to our qualitative classification the quantitative scheme of Kardashev. We propose a classification based on the abilities of ETCs to modify their environment and to integrate with it: Class 0 uses the environment as it is, Class 1 modifies the it to fit its needs, Class 2 modifies itself to fit the environment and Class 3 ETC is fully integrated with the environment. Combined with the classical Kardashev's scale our scheme forms a 2d scheme for interpreting ETC properties. The new framework makes it obvious that the available energy is not an unique measure of ETCs, it may not even correlate with how well that energy is used. The possibility for progress without increased energy consumption implies lower detectability, so the existence of a Kardashev Type III ETC in the Milky Way cannot be ruled out. This reasoning weakens the Fermi paradox, allowing the existence of advanced, yet not energy hungry, low detectability ETCs. The integration of ETCs with environment makes it impossible to tell apart technosignatures from natural phenomena. Thus, the most likely opportunity for SETI searches is to look for beacons, specifically set up by them for young civilizations like us (if they want to do that is a matter of speculation). The other SETI window is to search for ETCs at technological level close to ours. To rephrase the saying of A. Clarke, sufficiently advanced civilizations are indistinguishable from nature.

[53]  arXiv:2005.13280 (cross-list from hep-ph) [pdf, other]
Title: Modified majoron model for cosmological anomalies
Comments: 5 pages, 1 figure
Subjects: High Energy Physics - Phenomenology (hep-ph); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Astrophysical Phenomena (astro-ph.HE)

The vacuum expectation value $v_s$ of a Higgs triplet field $\Delta$ carrying two units of lepton number $L$ induces neutrino masses $\propto v_s$. The neutral component of $\Delta$ gives rise to two Higgs particles, a pseudoscalar $A$ and a scalar $S$. The most general renormalizable Higgs potential $V$ for $\Delta $ and the Standard-Model Higgs doublet $\Phi$ does not permit the possibility that the mass of either $A$ or $S$ is small, of order $v_s$, while the other mass is heavy enough to forbid the decay $Z\to A S$ to comply with LEP 1 data. We present a model with additional dimension-6 terms in $V$, in which this feature is absent and either $A$ or $S$ can be chosen light. Subsequently we propose the model as a remedy to cosmological anomalies, namely the tension between observed and predicted tensor-to-scalar mode ratios in the cosmic microwave background and the different values of the Hubble constant measured at different cosmological scales. Furthermore, if $\Delta$ dominantly couples to the third-generation doublet $L_\tau=(\nu_\tau,\tau)$, the deficit of $\nu_\tau$ events at IceCube can be explained. The singly and doubly charged triplet Higgs bosons are lighter than 280 GeV and 400 GeV respectively, and could be found at the LHC.

[54]  arXiv:2005.13384 (cross-list from hep-ph) [pdf, other]
Title: Dark Matter-Neutrino Interconversion at COHERENT, Direct Detection, and the Early Universe
Comments: 7 pages, 5 figures
Subjects: High Energy Physics - Phenomenology (hep-ph); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Experiment (hep-ex)

We study a Dark Matter (DM) model in which the dominant coupling to the standard model occurs through a neutrino-DM-scalar coupling. The new singlet scalar will generically have couplings to nuclei/electrons arising from renormalizable Higgs portal interactions. As a result the DM particle $X$ can convert into a neutrino via scattering on a target nucleus $\mathcal{N}$: $ X + \mathcal{N} \rightarrow \nu + \mathcal{N}$, leading to striking signatures at direct detection experiments. Similarly, DM can be produced in neutrino scattering events at neutrino experiments: $ \nu + \mathcal{N} \rightarrow X + \mathcal{N}$, predicting spectral distortions at experiments such as COHERENT. Furthermore, the model allows for late kinetic decoupling of dark matter with implications for small-scale structure. At low masses, we find that COHERENT and late kinetic decoupling produce the strongest constraints on the model, while at high masses the leading constraints come from DM down-scattering at XENON1T and Borexino. Future improvement will come from CE$\nu$NS data, ultra-low threshold direct detection, and rare kaon decays.

[55]  arXiv:2005.13464 (cross-list from gr-qc) [pdf, ps, other]
Title: Reply to note on "Boltzmann's H-theorem, entropy and the strength of gravity in theories with a nonminimal coupling between matter and geometry"
Authors: P. P. Avelino
Comments: 2 pages, no figures
Subjects: General Relativity and Quantum Cosmology (gr-qc); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Theory (hep-th)

In this brief reply we respond to the note of Bertolami and Gomes (arXiv:2005.03968) on our recent paper (arXiv:2003.10154).

Replacements for Thu, 28 May 20

[56]  arXiv:1906.06895 (replaced) [pdf, ps, other]
Title: Developing the radium measurement system for the water Cherenkov detector of the Jiangmen Underground Neutrino Observatory
Comments: 17 pages, 10 figures and 3 tables
Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); High Energy Physics - Experiment (hep-ex)
[57]  arXiv:1907.00088 (replaced) [pdf, ps, other]
Title: Using Random Forest Machine Learning Algorithms in Binary Supernovae Classification
Comments: 7 figures, withdrawn from ApJ, see note at end of paper
Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)
[58]  arXiv:1907.10735 (replaced) [pdf, other]
Title: EvryFlare II: Rotation Periods of the Cool Flare Stars in TESS Across Half the Southern Sky
Comments: 16 pages, 8 figures, 3 tables. Ancillary machine-readable files included. Accepted for publication in ApJ (proofs submitted). Includes significant new material, including starspot color that depends on stellar mass, more rotation periods, potential changes in activity during spin-down, and examples of binary rotators
Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Earth and Planetary Astrophysics (astro-ph.EP)
[59]  arXiv:1909.05277 (replaced) [pdf, other]
Title: Cosmological Parameters from the BOSS Galaxy Power Spectrum
Comments: 67 pages, 17 figures, some additional explanations and cross-checks added, version published in JCAP, likelihoods available at this https URL
Journal-ref: JCAP05(2020)042
Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Phenomenology (hep-ph)
[60]  arXiv:1909.09609 (replaced) [pdf, other]
Title: The Impact of Peculiar Velocities on the Estimation of the Hubble Constant from Gravitational Wave Standard Sirens
Comments: 9 pages, 5 figures
Journal-ref: MNRAS 495 (2020) 90-97
Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Astrophysics of Galaxies (astro-ph.GA); High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc)
[61]  arXiv:1910.13236 (replaced) [pdf, other]
Title: Deep Horizon; a machine learning network that recovers accreting black hole parameters
Comments: 13 pages, 10 figures, 2 tables
Journal-ref: A&A 636, A94 (2020)
Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc)
[62]  arXiv:1911.09113 (replaced) [pdf, other]
Title: The Role of Quasar Radiative Feedback on Galaxy Formation during Cosmic Reionization
Authors: Huanqing Chen
Comments: 13 pages, 14 figures, comments welcome
Subjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
[63]  arXiv:1911.13216 (replaced) [pdf, other]
Title: Effects of oscillating spacetime metric background on a complex scalar field and formation of topological vortices
Comments: 14 pages, 13 figures
Subjects: High Energy Physics - Theory (hep-th); High Energy Astrophysical Phenomena (astro-ph.HE); Quantum Gases (cond-mat.quant-gas); High Energy Physics - Phenomenology (hep-ph); Nuclear Theory (nucl-th)
[64]  arXiv:2001.02007 (replaced) [pdf, ps, other]
Title: Fast radio bursts from reconnection in magnetar magnetosphere
Authors: Yuri Lyubarsky
Comments: Sect. 3 is modified and Appendix B is added
Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)
[65]  arXiv:2001.04466 (replaced) [pdf, other]
Title: Precision Early Universe Thermodynamics made simple: $N_{\rm eff}$ and Neutrino Decoupling in the Standard Model and beyond
Authors: Miguel Escudero
Comments: 23 pages, 7 figures, 2 tables, 7 appendices. NUDEC_BSM code can be found at this https URL . Ancillary file contains the SM evolution as relevant for BBN. v2: Matches published version. Minor upgrades: refined parametrization of nu-e neutral current interactions in the SM, added a bonus section discussing Neff in the SM at full NLO. Results and conclusions remain unchanged
Subjects: High Energy Physics - Phenomenology (hep-ph); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
[66]  arXiv:2001.07014 (replaced) [pdf, other]
Title: eXTP perspectives for the $ν$MSM sterile neutrino dark matter model
Comments: Updated to match accepted version
Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); Instrumentation and Methods for Astrophysics (astro-ph.IM)
[67]  arXiv:2002.01286 (replaced) [pdf, other]
Title: Limits on primordial magnetic fields from primordial black hole abundance
Comments: 18 pages, 4 figures
Journal-ref: JCAP05(2020)039
Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc)
[68]  arXiv:2002.05243 (replaced) [pdf, other]
Title: Irradiated ocean planets bridge super-Earth and sub-Neptune populations
Comments: Accepted for publication in The Astrophysical Journal Letters
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
[69]  arXiv:2002.06711 (replaced) [pdf, other]
Title: A method of enhancing the detection sensitivity of transient sources in time series with Gaussian stationary noise
Comments: CQG in print
Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM)
[70]  arXiv:2002.11348 (replaced) [pdf, ps, other]
Title: Chiral Radiation Transport Theory of Neutrinos
Comments: 21 pages, no figures, very minor revisions, journal version
Journal-ref: Astrophys.J. 895 (2020) 1
Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics - Phenomenology (hep-ph); Nuclear Theory (nucl-th)
[71]  arXiv:2003.01100 (replaced) [pdf, other]
Title: The landscape of QCD axion models
Comments: Review article for Physics Reports, 151 pages. New parts added, relevant improvements to some sections, several corrections for typos and consistency of notations. Over one hundred new references added
Subjects: High Energy Physics - Phenomenology (hep-ph); Cosmology and Nongalactic Astrophysics (astro-ph.CO); Solar and Stellar Astrophysics (astro-ph.SR); High Energy Physics - Experiment (hep-ex); High Energy Physics - Theory (hep-th)
[72]  arXiv:2003.01731 (replaced) [pdf, other]
Title: The first dual-phase xenon TPC equipped with silicon photomultipliers and characterisation with $^{37}$Ar
Comments: 14 pages, 13 figures
Journal-ref: Eur. Phys. J. C 80, 477 (2020)
Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); High Energy Physics - Experiment (hep-ex); Nuclear Experiment (nucl-ex); Instrumentation and Detectors (physics.ins-det)
[73]  arXiv:2003.04839 (replaced) [pdf, other]
Title: Optimal Gravitational-wave Follow-up Tiling Strategies Using a Genetic Algorithm
Comments: 8 pages, 5 figures. Accepted in PRD
Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); High Energy Astrophysical Phenomena (astro-ph.HE)
[74]  arXiv:2003.06753 (replaced) [pdf, other]
Title: Escape from the swamp with spectator
Comments: 10 pages, 4 figures; v2: published version
Journal-ref: Phys. Rev. D 101, 103514 (2020)
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)
[75]  arXiv:2003.10154 (replaced) [pdf, ps, other]
Title: Boltzmann's $H$-theorem, entropy and the strength of gravity in theories with a nonminimal coupling between matter and geometry
Comments: 7 pages, no figures. Clarifications added, typos corrected. Results unchanged
Subjects: General Relativity and Quantum Cosmology (gr-qc); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Theory (hep-th)
[76]  arXiv:2003.11104 (replaced) [pdf, other]
Title: Thermally Unstable Cooling Stimulated by Uplift: The Spoiler Clusters
Comments: Accepted for publication in ApJ. The draft includes significant changes to the Introduction intended to better motivate this work by placing the problem in the context of current theoretical understanding of thermally unstable cooling. The abstract and conclusion were edited for clarity
Subjects: Astrophysics of Galaxies (astro-ph.GA)
[77]  arXiv:2004.01666 (replaced) [pdf, other]
Title: Post-Limber Weak Lensing Bispectrum, Reduced Shear Correction, and Magnification Bias Correction
Comments: 12 pages, 4 figures. Accepted by Phys. Rev. D. Matches published version
Journal-ref: Phys. Rev. D 101, 103531 (2020)
Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
[78]  arXiv:2004.02963 (replaced) [pdf, other]
Title: Multipole alignment in the large-scale distribution of spin direction of spiral galaxies
Authors: Lior Shamir
Comments: To be submitted. Comments welcome
Subjects: Astrophysics of Galaxies (astro-ph.GA)
[79]  arXiv:2004.12096 (replaced) [pdf, other]
Title: Multiband Observation of LIGO/Virgo Binary Black Hole Mergers in the Gravitational-wave Transient Catalog GWTC-1
Comments: 16 pages, 5 figures, 6 tables; accepted by MNRAS
Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc)
[80]  arXiv:2005.01744 (replaced) [pdf, ps, other]
Title: Symmetries from Locality Part 2: Gravitation and Lorentz Boosts
Comments: 12 pages in double column format. V2 further clarification and fixed some typos
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)
[81]  arXiv:2005.04239 (replaced) [pdf, other]
Title: GW190412 as a Third-Generation Black Hole Merger from a Super Star Cluster
Comments: 9 pages, 4 figures, matches version accepted by ApJL
Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc)
[82]  arXiv:2005.05446 (replaced) [pdf, other]
Title: The IACOB project. VI. On the elusive detection of massive O-type stars close to the ZAMS
Authors: G. Holgado (1,2,3), S. Simón-Díaz (2,3), L. Haemmerlé (4), D. J. Lennon (2,3), R. H. Barbá (5), M. Cerviño (1), N. Castro (6), A.Herrero (2,3), G. Meynet (4), J. I. Arias (5)
Comments: 20 pages, 15 figures, accepted for publication in Astronomy & Astrophysics
Subjects: Solar and Stellar Astrophysics (astro-ph.SR)
[83]  arXiv:2005.06325 (replaced) [pdf, other]
Title: Constraining the growth rate of structure with phase correlations
Comments: 27 pages, 13 figures, 2 tables. v2 has additional discussion on model-independence of the forecasts. Submitted to MNRAS
Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
[84]  arXiv:2005.07721 (replaced) [pdf, other]
Title: Fast Blast Wave and Ejecta in the Young Core-Collapse Supernova Remnant MSH 15-52/RCW 89
Comments: 7 pages, 4 figures, minor revisions, accepted for publication in ApJ Letters
Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)
[85]  arXiv:2005.08937 (replaced) [pdf, ps, other]
Title: High-Energy Neutrino and Gamma-Ray Emission from Tidal Disruption Events
Comments: 16 pages, 6 figures, 1 table, submitted, typos fixed and discussions/references added
Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics - Phenomenology (hep-ph)
[86]  arXiv:2005.09168 (replaced) [pdf, other]
Title: Constraining sterile neutrinos by core-collapse supernovae with multiple detectors
Comments: 24 pages, 12 figures, 4 tables
Subjects: High Energy Physics - Phenomenology (hep-ph); Astrophysics of Galaxies (astro-ph.GA); High Energy Astrophysical Phenomena (astro-ph.HE)
[87]  arXiv:2005.11479 (replaced) [pdf, other]
Title: Stringent upper limits on pulsed radio emission during an active bursting phase of the Galactic magnetar SGRJ1935+2154
Comments: 28 pages, 7 figures, This version submitted to Nature. Subject to press embargo
Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)
[88]  arXiv:2005.12048 (replaced) [pdf, ps, other]
Title: A Magnetar-Asteroid Impact Model for FRB 200428 Associated with an X-ray Burst from SGR 1935+2154
Authors: Z. G. Dai (NJU)
Comments: 5 pages in emulateapj format, 2 figures, a few typos corrected, references updated
Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)
[89]  arXiv:2005.12117 (replaced) [pdf, other]
Title: Extended X-ray emission from the classic nova DQ Her -- On the possible presence of a magnetized jet
Comments: 8 pages, 4 figures, 1 table; accepted to MNRAS
Subjects: Solar and Stellar Astrophysics (astro-ph.SR); High Energy Astrophysical Phenomena (astro-ph.HE)
[90]  arXiv:2005.12471 (replaced) [pdf, other]
Title: K-CLASH: spatially-resolving star-forming galaxies in field and cluster environments at $z \approx 0.2$-$0.6$
Authors: Alfred L. Tiley (1,2,3), Sam P. Vaughan (4,5,3), John P. Stott (6), Roger L. Davies (3), Laura J. Prichard (7), Andrew Bunker (3), Martin Bureau (3,8), Michele Cappellari (3), Matt Jarvis (3,9), Aaron Robotham (1), Luca Cortese (1,5), Sabine Bellstedt (1), Behzad Ansarinejad (2) ((1) ICRAR/UWA, (2) CEA Durham University, (3) University of Oxford, (4) SIfA University of Sydney, (5) ASTRO3D, (6) Lancaster University, (7) STScI, (8) Yonsei University, (9) University of the Western Cape)
Comments: Accepted for publication in MNRAS, 31 pages, 15 figures, 2 tables; updated to correct typos in Section 5.2
Subjects: Astrophysics of Galaxies (astro-ph.GA)
[91]  arXiv:2005.12507 (replaced) [pdf, other]
Title: Selection of massive evolved galaxies at $3 \leq z \leq 4.5$ in the CANDELS fields
Comments: 20 pages, 11 figures, Accepted for publication in ApJ
Subjects: Astrophysics of Galaxies (astro-ph.GA)
[92]  arXiv:2005.12829 (replaced) [pdf, other]
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