RAS_WEB (Page 2,336)

Radiation hydrodynamics simulations of protoplanetary disks: Stellar mass dependence of the disk photoevaporation rate. (arXiv:2012.14852v3 [astro-ph.EP] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Komaki_A/0/1/0/all/0/1">Ayano Komaki</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Nakatani_R/0/1/0/all/0/1">Riouhei Nakatani</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Yoshida_N/0/1/0/all/0/1">Naoki Yoshida</a> Recent multi-wavelength observations suggest that inner parts of protoplanetary disks (PPDs) have shorter lifetimes for heavier host stars. Since PPDs around high-mass stars are irradiated by strong ultra-violet radiation, photoevaporation may provide an explanation for the observed trend. We perform radiation hydrodynamics simulations of photoevaporation of PPDs for a wide range of host star mass of $M_* =0.5$-$7.0 M_{odot}$. We derive disk mass-loss rate $dot{M}$, which has strong stellar dependence as $dot{M} approx 7.30times10^{-9}(M_{*}/M_{odot})^{2}M_{odot}rm{yr}^{-1}$. The absolute value of $dot{M}$Read More →

Multi-messenger Probes of Inflationary Fluctuations and Primordial Black Holes. (arXiv:2008.11184v3 [astro-ph.CO] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Unal_C/0/1/0/all/0/1">Caner Unal</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kovetz_E/0/1/0/all/0/1">Ely D. Kovetz</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Patil_S/0/1/0/all/0/1">Subodh P. Patil</a> Next generation cosmic microwave background spectral distortion and pulsar timing array experiments have the potential to probe primordial fluctuations at small scales with remarkable sensitivity. We demonstrate the potential of these probes to either detect signatures of primordial black holes (PBHs) sourced from primordial overdensities within the standard thermal history of the universe over a 13-decade mass range ${cal O}(0.1-10^{12})M_odot$, or constrain their existence to a negligible abundance. Our conclusions are based only on global cosmological signals, and are robust under changesRead More →

No escaping helium from 55 Cnc e. (arXiv:2012.02198v2 [astro-ph.EP] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Zhang_M/0/1/0/all/0/1">Michael Zhang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Knutson_H/0/1/0/all/0/1">Heather A. Knutson</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wang_L/0/1/0/all/0/1">Lile Wang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Dai_F/0/1/0/all/0/1">Fei Dai</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Oklopcic_A/0/1/0/all/0/1">Antonija Oklopcic</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hu_R/0/1/0/all/0/1">Renyu Hu</a> We search for escaping helium from the hot super Earth 55 Cnc e by taking high-resolution spectra of the 1083 nm line during two transits using Keck/NIRSPEC. We detect no helium absorption down to a 90% upper limit of 250 ppm in excess absorption or 0.27 milli-Angstrom in equivalent width. This corresponds to a mass loss rate of less than $sim10^9$ g/s assuming a Parker wind model with a plausible exosphere temperature of 5000-6000 K, althoughRead More →

Intrinsic Correlations Among Characteristics of Neutron-rich Matter Imposed by the Unbound Nature of Pure Neutron Matter. (arXiv:2012.01549v2 [nucl-th] UPDATED) <a href="http://arxiv.org/find/nucl-th/1/au:+Cai_B/0/1/0/all/0/1">Bao-Jun Cai</a>, <a href="http://arxiv.org/find/nucl-th/1/au:+Li_B/0/1/0/all/0/1">Bao-An Li</a> The unbound nature of pure neutron matter (PNM) requires intrinsic correlations between the symmetric nuclear matter (SNM) EOS parameters (incompressibility $K_0$, skewness $J_0$ and kurtosis $I_0$) and those (slope $L$, curvature $K_{rm{sym}}$ and skewness $J_{rm{sym}}$) characterizing the symmetry energy independent of any nuclear many-body theory. We investigate these intrinsic correlations and their applications in better constraining the poorly known high-density behavior of nuclear symmetry energy. Several novel correlations connecting the characteristics of SNM EOS with those of nuclear symmetry energyRead More →

Precession of spheroids under Lorentz violation and observational consequences for neutron stars. (arXiv:2012.01320v3 [gr-qc] UPDATED) <a href="http://arxiv.org/find/gr-qc/1/au:+Xu_R/0/1/0/all/0/1">Rui Xu</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Gao_Y/0/1/0/all/0/1">Yong Gao</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Shao_L/0/1/0/all/0/1">Lijing Shao</a> The Standard-Model Extension (SME) is an effective-field-theoretic framework that catalogs all Lorentz-violating field operators. The anisotropic correction from the minimal gravitational SME to Newtonian gravitational energy for spheroids is studied, and the rotation of rigid spheroids is solved with perturbation method and numerical approach. The well-known forced precession solution given by Nordtvedt in the parameterized post-Newtonian formalism is recovered and applied to two observed solitary millisecond pulsars to set bounds on the coefficients for Lorentz violation in the SME framework. ARead More →

Fast methods to track grain coagulation and ionization. I. Analytic derivation. (arXiv:2103.00002v1 [astro-ph.GA]) <a href="http://arxiv.org/find/astro-ph/1/au:+Marchand_P/0/1/0/all/0/1">Pierre Marchand</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Guillet_V/0/1/0/all/0/1">Vincent Guillet</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lebreuilly_U/0/1/0/all/0/1">Ugo Lebreuilly</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Low_M/0/1/0/all/0/1">Mordecai-Mark Mac Low</a> Dust grains play a major role in many astrophysical contexts. They influence the chemical, magnetic, dynamical and optical properties of their environment, from galaxies down to the interstellar medium, star-forming regions, and protoplanetary disks. Their coagulation leads to shifts in their size distribution and ultimately to the formation of planets. However, although the coagulation process is reasonably uncomplicated to implement numerically by itself, it is difficult to couple it with multi-dimensional hydrodynamics numerical simulations because of its high computationalRead More →

Searching for the full symphony of black hole binary mergers. (arXiv:1709.09181v2 [gr-qc] UPDATED) <a href="http://arxiv.org/find/gr-qc/1/au:+Harry_I/0/1/0/all/0/1">Ian Harry</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Bustillo_J/0/1/0/all/0/1">Juan Calder&#xf3;n Bustillo</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Nitz_A/0/1/0/all/0/1">Alex Nitz</a> Current searches for the gravitational-wave signature of compact binary mergers rely on matched-filtering data from interferometric observatories with sets of modelled gravitational waveforms. These searches currently use model waveforms that do not include the higher-order mode content of the gravitational-wave signal. Higher-order modes are important for many compact binary mergers and their omission reduces the sensitivity to such sources. In this work we explore the sensitivity loss incurred from omitting higher-order modes. We present a new method for searching for compact binaryRead More →

Quasi Band-Limited Coronagraph for Extended Sources. (arXiv:2007.06785v2 [astro-ph.IM] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Loutsenko_I/0/1/0/all/0/1">Igor Loutsenko</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Yermolayeva_O/0/1/0/all/0/1">Oksana Yermolayeva</a> We propose a class of graded coronagraphic “amplitude” image masks for a high throughput Lyot-type coronagraph that transmits light from an annular region around an extended source and suppresses light, with extremely high ratio, from elsewhere. The interior radius of the region is comparable with its exterior radius. The masks are designed using an idea inspired by approach due M.J. Kuchner and W.A. Traub (“band-limited” masks) and approach to optimal apodization by D.Slepian. One potential application of our masks is direct high-resolution imaging of exo-planets with the help of theRead More →

Einstein-Gauss-Bonnet gravity: is it compatible with modern cosmology?. (arXiv:2007.06730v2 [astro-ph.CO] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Garcia_Aspeitia_M/0/1/0/all/0/1">Miguel A. Garc&#xed;a-Aspeitia</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hernandez_Almada_A/0/1/0/all/0/1">A. Hern&#xe1;ndez-Almada</a> Einstein-Gauss-Bonnet (EGB) model is recently restudied in order to analyze new consequences in gravitation, modifying appropriately the Einstein-Hilbert action. The consequences in EGB cosmology are mainly geometric, with higher order values in the Hubble parameter. In this vein this paper is devoted to contribute with extra evidences about its pros and cons of the model from a cosmological point of view. We start constraining the characteristic parameter, $alpha$, of the EGB model when a cosmological constant as the catalyst for the acceleration is considered. The constrictions areRead More →

Signatures of Einstein-Maxwell dilaton-axion gravity from the observed jet power and the radiative efficiency. (arXiv:2007.03947v2 [gr-qc] UPDATED) <a href="http://arxiv.org/find/gr-qc/1/au:+Banerjee_I/0/1/0/all/0/1">Indrani Banerjee</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Mandal_B/0/1/0/all/0/1">Bhaswati Mandal</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+SenGupta_S/0/1/0/all/0/1">Soumitra SenGupta</a> The Einstein-Maxwell dilaton-axion (EMDA) gravity arises in the low energy effective action of the heterotic string theory and provides a simple framework to explore the signatures of the same. The dilaton and the axion fields inherited in the action from string compactifications have interesting consequences in inflationary cosmology and in explaining the present accelerated expansion of the universe. It is therefore worthwhile to search for the footprints of these fields in the available astrophysical observations. Since Einstein gravity isRead More →

Long-range enhanced mutual information from inflation. (arXiv:2007.02828v2 [gr-qc] UPDATED) <a href="http://arxiv.org/find/gr-qc/1/au:+Espinosa_Portales_L/0/1/0/all/0/1">Lloren&#xe7; Espinosa-Portal&#xe9;s</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Garcia_Bellido_J/0/1/0/all/0/1">Juan Garc&#xed;a-Bellido</a> The quantum origin of cosmological primordial perturbations is a cornerstone framework in the interplay between gravity and quantum physics. In this paper we study the mutual information between two spatial regions in a radiation-dominated universe filled by a curvature perturbation field in a squeezed state. We find an enhancement with respect to the usual mutual information of the Minkowski vacuum due to momentum modes affected by particle production during inflation. This result supports our previous claim of the existence of long-range correlations between Primordial Black Holes (PBH) at formation duringRead More →

Using Cosmic Rays detected by HST as Geophysical Markers I: Detection and Characterization of Cosmic Rays. (arXiv:2006.00909v2 [astro-ph.IM] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Miles_N/0/1/0/all/0/1">Nathan Miles</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Deustua_S/0/1/0/all/0/1">Susana E. Deustua</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Tancredi_G/0/1/0/all/0/1">Gonzalo Tancredi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Schnyder_G/0/1/0/all/0/1">German Schnyder</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Nesmachnow_S/0/1/0/all/0/1">Sergio Nesmachnow</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cromwell_G/0/1/0/all/0/1">Geoffrey Cromwell</a> The Hubble Space Telescope (HST) has been operational for over 30 years and throughout that time it has been bombarded by high energy charged particles colloquially referred to as cosmic rays. In this paper, we present a comprehensive study of more than 1.2 billion cosmic rays observed with HST using a custom written python package, texttt{HSTcosmicrays}, that is available to the astronomical community. We analyzed $75,908$ darkRead More →

Kinematics of the Circumgalactic Medium of a $z = 0.77$ Galaxy from MgII Tomography. (arXiv:2006.00006v2 [astro-ph.GA] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Mortensen_K/0/1/0/all/0/1">Kris Mortensen</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+C%2E_K/0/1/0/all/0/1">Keerthi Vasan G.C.</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Jones_T/0/1/0/all/0/1">Tucker Jones</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Faucher_Giguere_C/0/1/0/all/0/1">Claude-Andre Faucher-Giguere</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sanders_R/0/1/0/all/0/1">Ryan Sanders</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ellis_R/0/1/0/all/0/1">Richard S. Ellis</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Leethochawalit_N/0/1/0/all/0/1">Nicha Leethochawalit</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Stark_D/0/1/0/all/0/1">Daniel P. Stark</a> Galaxy evolution is thought to be driven in large part by the flow of gas between galaxies and the circumgalactic medium (CGM), a halo of metal-enriched gas extending out to $gtrsim100$ kpc from each galaxy. Studying the spatial structure of the CGM holds promise for understanding these gas flow mechanisms; however, the common method using background quasar sightlines provides minimal spatialRead More →

Astraeus I: The interplay between galaxy formation and reionization. (arXiv:2004.08401v2 [astro-ph.GA] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Hutter_A/0/1/0/all/0/1">Anne Hutter</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Dayal_P/0/1/0/all/0/1">Pratika Dayal</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Yepes_G/0/1/0/all/0/1">Gustavo Yepes</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gottlober_S/0/1/0/all/0/1">Stefan Gottl&#xf6;ber</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Legrand_L/0/1/0/all/0/1">Laurent Legrand</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ucci_G/0/1/0/all/0/1">Graziano Ucci</a> We introduce a new self-consistent model of galaxy evolution and reionization, ASTRAEUS (semi-numerical rAdiative tranSfer coupling of galaxy formaTion and Reionization in N-body dArk mattEr simUlationS), which couples a state-of-the-art N-body simulation with the semi-analytical galaxy evolution DELPHI and the semi-numerical reionization scheme CIFOG. ASTRAEUS includes all the key processes of galaxy formation and evolution (including accretion, mergers, supernova and radiative feedback) and follows the time and spatial evolution of the ionized regions in theRead More →

Spherical harmonic analysis of anisotropies in polarized stochastic gravitational wave background with interferometry experiments. (arXiv:2002.01606v3 [gr-qc] UPDATED) <a href="http://arxiv.org/find/gr-qc/1/au:+Chu_Y/0/1/0/all/0/1">Yu-Kuang Chu</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Liu_G/0/1/0/all/0/1">Guo-Chin Liu</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Ng_K/0/1/0/all/0/1">Kin-Wang Ng</a> We study the interferometric observation of intensity and polarization anisotropies of a stochastic gravitational wave background (SGWB). We show that the observed correlated data is defined in the group manifold of the three-dimensional rotation. Explicit correlation between two detectors in the interferometry experiments such as LIGO-Virgo and KAGRA is constructed in terms of the Wigner D-functions. Our results may provide a tool for constructing data pipelines to estimate the power spectra of the SGWB anisotropies. We study the interferometricRead More →

Testing the effect of $H_0$ on $fsigma_8$ tension using a Gaussian Process method. (arXiv:1911.12076v2 [astro-ph.CO] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Li_E/0/1/0/all/0/1">En-Kun Li</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Du_M/0/1/0/all/0/1">Minghui Du</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Zhou_Z/0/1/0/all/0/1">Zhi-Huan Zhou</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Zhang_H/0/1/0/all/0/1">Hongchao Zhang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Xu_L/0/1/0/all/0/1">Lixin Xu</a> Using the $fsigma_8(z)$ redshift space distortion (RSD) data, the $sigma_8^0-Omega_m^0$ tension is studied utilizing a parameterization of growth rate $f(z) = Omega_m(z)^gamma$. Here, $f(z)$ is derived from the expansion history $H(z)$ which is reconstructed from the observational Hubble data applying the Gaussian Process method. It is found that different priors of $H_0$ have great influences on the evolution curve of $H(z)$ and the constraint of $sigma_8^0-Omega_m^0$. When using a larger $H_0$ prior, the lowRead More →

Timing the Neutrino Signal of a Galactic Supernova. (arXiv:1904.11461v2 [hep-ph] UPDATED) <a href="http://arxiv.org/find/hep-ph/1/au:+Hansen_R/0/1/0/all/0/1">Rasmus S. L. Hansen</a>, <a href="http://arxiv.org/find/hep-ph/1/au:+Lindner_M/0/1/0/all/0/1">Manfred Lindner</a>, <a href="http://arxiv.org/find/hep-ph/1/au:+Scholer_O/0/1/0/all/0/1">Oliver Scholer</a> We study several methods for timing the neutrino signal of a Galactic supernova (SN) for different detectors via Monte Carlo simulations. We find that, for the methods we studied, at a distance of $10,$kpc both Hyper-Kamiokande and IceCube can reach precisions of $sim1,$ms for the neutrino burst, while a potential IceCube Gen2 upgrade will reach submillisecond precision. In the case of a failed SN, we find that detectors such as SK and JUNO can reach precisions of $sim0.1,$ms while HK could potentially reachRead More →

A catalog of stereo anaglyphs of the nucleus of comet 67P/Churyumov-Gerasimenko. (arXiv:1903.02324v2 [astro-ph.EP] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Lamy_P/0/1/0/all/0/1">Philippe Lamy</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Faury_G/0/1/0/all/0/1">Guillaume Faury</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Romeuf_D/0/1/0/all/0/1">David Romeuf</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Groussin_O/0/1/0/all/0/1">Olivier Groussin</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Durand_J/0/1/0/all/0/1">Joelle Durand</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Beigbeder_L/0/1/0/all/0/1">Laurent Beigbeder</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Khum_K/0/1/0/all/0/1">Kea Khum</a> The OSIRIS/NAC camera onboard the Rosetta spacecraft acquired approximately 27000 images of comet 67PChuryumov-Gerasimenko at spatial scales down to a few centimeters. Numerous sequences of images separated by a few minutes suitable to stereo reconstruction allowed producing anaglyphs. They offer three-dimensional views complementary to other technics as a tool to understand the topography of the nucleus. Each one is documented by a set of 17 parameters. Over 1820 anaglyphs areRead More →

Magnetic Fields in the Milky Way and in Galaxies (revised version of March 2021). (arXiv:1302.5663v7 [astro-ph.GA] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Beck_R/0/1/0/all/0/1">Rainer Beck</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wielebinski_R/0/1/0/all/0/1">Richard Wielebinski</a> Most of the visible matter in the Universe is ionized, so that cosmic magnetic fields are quite easy to generate and due to the lack of magnetic monopoles hard to destroy. Magnetic fields have been measured in or around practically all celestial objects, either by in-situ measurements of spacecrafts or by the electromagnetic radiation of embedded cosmic rays, gas, or dust. The Earth, the Sun, solar planets, stars, pulsars, the Milky Way, nearby galaxies, more distant (radio) galaxies, quasars, and even intergalacticRead More →