RAS_WEB (Page 2,675)

A warm Jupiter transiting an M dwarf: A TESS single transit event confirmed with the Habitable-zone Planet Finder. (arXiv:2007.07098v2 [astro-ph.EP] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Canas_C/0/1/0/all/0/1">Caleb I. Ca&#xf1;as</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Stefansson_G/0/1/0/all/0/1">Gudmundur Stefansson</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kanodia_S/0/1/0/all/0/1">Shubham Kanodia</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Mahadevan_S/0/1/0/all/0/1">Suvrath Mahadevan</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cochran_W/0/1/0/all/0/1">William D. Cochran</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Endl_M/0/1/0/all/0/1">Michael Endl</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Robertson_P/0/1/0/all/0/1">Paul Robertson</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bender_C/0/1/0/all/0/1">Chad F. Bender</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ninan_J/0/1/0/all/0/1">Joe P. Ninan</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Beard_C/0/1/0/all/0/1">Corey Beard</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lubin_J/0/1/0/all/0/1">Jack Lubin</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gupta_A/0/1/0/all/0/1">Arvind F. Gupta</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Everett_M/0/1/0/all/0/1">Mark E. Everett</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Monson_A/0/1/0/all/0/1">Andrew Monson</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wilson_R/0/1/0/all/0/1">Robert F. Wilson</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lewis_H/0/1/0/all/0/1">Hannah M. Lewis</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Brewer_M/0/1/0/all/0/1">Mary Brewer</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Majewski_S/0/1/0/all/0/1">Steven R. Majewski</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hebb_L/0/1/0/all/0/1">Leslie Hebb</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Dawson_R/0/1/0/all/0/1">Rebekah I. Dawson</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Diddams_S/0/1/0/all/0/1">Scott A. Diddams</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ford_E/0/1/0/all/0/1">Eric B. Ford</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Fredrick_C/0/1/0/all/0/1">Connor Fredrick</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Halverson_S/0/1/0/all/0/1">Samuel Halverson</a>,Read More →

Luminous supernovae associated with ultra-long gamma-ray bursts from hydrogen-free progenitors extended by pulsational pair-instability. (arXiv:2007.06221v2 [astro-ph.HE] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Moriya_T/0/1/0/all/0/1">Takashi J. Moriya</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Marchant_P/0/1/0/all/0/1">Pablo Marchant</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Blinnikov_S/0/1/0/all/0/1">Sergei I. Blinnikov</a> We show that the luminous supernovae (SNe) associated with ultra-long gamma-ray bursts (GRBs) can be related to the slow cooling from the explosions of hydrogen-free progenitors extended by pulsational pair-instability. In the accompanying paper (Marchant & Moriya 2020), we have shown that some rapidly-rotating hydrogen-free GRB progenitors that experience pulsational pair-instability can keep an extended structure caused by pulsational pair-instability until the core collapse. Such progenitors have large radii exceeding 10 Rsun and they sometimes reach beyondRead More →

Probing Dark Low-mass Halos and Primordial Black Holes with Frequency-dependent Gravitational Lensing Dispersions of Gravitational Waves. (arXiv:2007.01936v2 [astro-ph.CO] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Oguri_M/0/1/0/all/0/1">Masamune Oguri</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Takahashi_R/0/1/0/all/0/1">Ryuichi Takahashi</a> We explore the possibility of using amplitude and phase fluctuations of gravitational waves due to gravitational lensing as a probe of the small-scale matter power spectrum. The direct measurement of the small-scale matter power spectrum is made possible by making use of the frequency dependence of such gravitational lensing dispersions originating from the wave optics nature of the propagation of gravitational waves. We first study the small-scale behavior of the matter power spectrum in detail taking the so-called halo modelRead More →

Oblique tearing mode instability: guide field and Hall effect. (arXiv:2007.00607v3 [physics.plasm-ph] UPDATED) <a href="http://arxiv.org/find/physics/1/au:+Shi_C/0/1/0/all/0/1">Chen Shi</a>, <a href="http://arxiv.org/find/physics/1/au:+Velli_M/0/1/0/all/0/1">Marco Velli</a>, <a href="http://arxiv.org/find/physics/1/au:+Pucci_F/0/1/0/all/0/1">Fulvia Pucci</a>, <a href="http://arxiv.org/find/physics/1/au:+Tenerani_A/0/1/0/all/0/1">Anna Tenerani</a>, <a href="http://arxiv.org/find/physics/1/au:+Innocenti_M/0/1/0/all/0/1">Maria Elena Innocenti</a> The tearing mode instability is one important mechanism that may explain the triggering of fast magnetic reconnection in astrophysical plasmas such as the solar corona and the Earth’s magnetosphere. In this paper, the linear stability analysis of the tearing mode is carried out for a current sheet in the presence of a guide field, including the Hall effect. We show that the presence of a strong guide field does not modify the most unstable mode in theRead More →

Periodic Windowed Behavior in SGR1935+2154 SGR Bursts. (arXiv:2006.16480v4 [astro-ph.HE] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Grossan_B/0/1/0/all/0/1">Bruce Grossan</a> Two repeating FRB sources, FRB180916 (CHIME/FRB Collaboration, 2020) and FRB121102 (Rajwade, et al., 2020) display periodic windowed behavior (PWB) in the times of FRB detections. In PWB, events occur only within a periodic window spanning some fraction of the period, but additionally, in FRB121102, no events are detected at all during many of the periods. During 2020 May, coincident soft gamma bursts and fast radio bursts (FRBs) observed from SGR1935+2154 (Zhang, et al., 2020) established a clear link between at least some FRBs and soft gamma repeaters (SGR), and therefore magnetars. TheRead More →

Three-component modelling of C-rich AGB star winds V. Effects of frequency-dependent radiative transfer including drift. (arXiv:2006.11296v2 [astro-ph.SR] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Sandin_C/0/1/0/all/0/1">Christer Sandin</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Mattsson_L/0/1/0/all/0/1">Lars Mattsson</a> Stellar winds of cool carbon stars enrich the interstellar medium with significant amounts of carbon and dust. We present a study of the influence of two-fluid flow on winds where we add descriptions of frequency-dependent radiative transfer. Our radiation hydrodynamic models in addition include stellar pulsations, grain growth and ablation, gas-to-dust drift using one mean grain size, dust extinction based on both the small particle limit and Mie scattering, and an accurate numerical scheme. We calculate models at high spatial resolutionRead More →

Standing on the shoulders of giants: New mass and distance estimates for Betelgeuse through combined evolutionary, asteroseismic, and hydrodynamical simulations with MESA. (arXiv:2006.09837v4 [astro-ph.SR] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Joyce_M/0/1/0/all/0/1">Meridith Joyce</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Leung_S/0/1/0/all/0/1">Shing-Chi Leung</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Molnar_L/0/1/0/all/0/1">L&#xe1;szl&#xf3; Moln&#xe1;r</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ireland_M/0/1/0/all/0/1">Michael J. Ireland</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kobayashi_C/0/1/0/all/0/1">Chiaki Kobayashi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Nomoto_K/0/1/0/all/0/1">Ken&#x27;ichi Nomoto</a> We conduct a rigorous examination of the nearby red supergiant Betelgeuse by drawing on the synthesis of new observational data and three different modeling techniques. Our observational results include the release of new, processed photometric measurements collected with the space-based SMEI instrument prior to Betelgeuse’s recent, unprecedented dimming event. We detect the first radial overtone in the photometric data and reportRead More →

Pair separation in parallel electric field in magnetar magnetosphere and narrow spectra of fast radio bursts. (arXiv:2006.03270v2 [astro-ph.HE] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Yang_Y/0/1/0/all/0/1">Yuan-Pei Yang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Zhu_J/0/1/0/all/0/1">Jin-Ping Zhu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Zhang_B/0/1/0/all/0/1">Bing Zhang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wu_X/0/1/0/all/0/1">Xue-Feng Wu</a> When the magnetosphere of a magnetar is perturbed by crustal deformation, an electric field $E_parallel$ parallel to the magnetic field line would appear via Alvf’en waves in the charge starvation region. The electron-positron pair bunches will be generated via two-stream instability in the magnetosphere, and these pairs will undergo charge separation in the $E_parallel$ and in the meantime emit coherent curvature radiation. Following the approach of Yang & Zhang (2018), we find that theRead More →

Convectively Driven Three Dimensional Turbulence in Massive Star Envelopes: I. A 1D Implementation of Diffusive Radiative Transport. (arXiv:2009.01238v1 [astro-ph.SR]) <a href="http://arxiv.org/find/astro-ph/1/au:+Schultz_W/0/1/0/all/0/1">William Schultz</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bildsten_L/0/1/0/all/0/1">Lars Bildsten</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Jiang_Y/0/1/0/all/0/1">Yan-Fei Jiang</a> Massive ($M >30,$M$_{odot}$) stars exhibit luminosities that are near the Eddington-limit for electron scattering causing the increase in opacity associated with iron at $Tapprox180,000,$K to trigger supersonic convection in their outer envelopes. Three dimensional radiative hydrodynamics simulations by Jiang and collaborators with the Athena++ computational tool have found order of magnitude density and radiative flux fluctuations in these convective regions, even at optical depths $gg100$. We show here that radiation can diffuse out of a parcel duringRead More →

Full Transport General Relativistic Radiation Magnetohydrodynamics for Nucleosynthesis in Collapsars. (arXiv:1912.03378v2 [astro-ph.HE] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Miller_J/0/1/0/all/0/1">Jonah M. Miller</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sprouse_T/0/1/0/all/0/1">Trevor M. Sprouse</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Fryer_C/0/1/0/all/0/1">Christopher L. Fryer</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ryan_B/0/1/0/all/0/1">Benjamin R. Ryan</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Dolence_J/0/1/0/all/0/1">Joshua C. Dolence</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Mumpower_M/0/1/0/all/0/1">Matthew R. Mumpower</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Surman_R/0/1/0/all/0/1">Rebecca Surman</a> We model a compact black hole-accretion disk system in the collapsar scenario with full transport, frequency dependent, general relativistic radiation magnetohydrodynamics. We examine whether or not winds from a collapsar disk can undergo rapid neutron capture (r-process) nucleosynthesis and significantly contribute to solar r-process abundances. We find the inclusion of accurate transport has significant effects on outflows, raising the electron fraction above $Y_{rm e} simRead More →

A comparison of $text{H}_2$ formation models at high redshift. (arXiv:2003.04329v2 [astro-ph.GA] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Schabe_A/0/1/0/all/0/1">Alexander Sch&#xe4;be</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Romano_Diaz_E/0/1/0/all/0/1">Emilio Romano-D&#xed;az</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Porciani_C/0/1/0/all/0/1">Cristiano Porciani</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ludlow_A/0/1/0/all/0/1">Aaron D. Ludlow</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Tomassetti_M/0/1/0/all/0/1">Matteo Tomassetti</a> Modelling the molecular gas that is routinely detected through CO observations of high-redshift galaxies constitutes a major challenge for ab initio simulations of galaxy formation. We carry out a suite of cosmological hydrodynamic simulations to compare three approximate methods that have been used in the literature to track the formation and evolution of the simplest and most abundant molecule, H$_2$. Namely, we consider: i) a semi-empirical procedure that associates H$_2$ to dark-matter haloes based on a seriesRead More →

Characterizing the continuous gravitational-wave signal from boson clouds around Galactic isolated black holes. (arXiv:2003.03359v2 [gr-qc] UPDATED) <a href="http://arxiv.org/find/gr-qc/1/au:+Zhu_S/0/1/0/all/0/1">Sylvia J. Zhu</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Baryakhtar_M/0/1/0/all/0/1">Masha Baryakhtar</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Papa_M/0/1/0/all/0/1">Maria Alessandra Papa</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Tsuna_D/0/1/0/all/0/1">Daichi Tsuna</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Kawanaka_N/0/1/0/all/0/1">Norita Kawanaka</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Eggenstein_H/0/1/0/all/0/1">Heinz-Bernd Eggenstein</a> Ultralight bosons can form large clouds around stellar-mass black holes via the superradiance instability. Through processes such as annihilation, these bosons can source continuous gravitational wave signals with frequencies within the range of LIGO and Virgo. If boson annihilation occurs, then the Galactic black hole population will give rise to many gravitational signals; we refer to this as the ensemble signal. We characterize the ensemble signal as observed byRead More →

Improved neutrino-nucleon interactions in dense and hot matter for numerical simulations. (arXiv:2003.02152v2 [astro-ph.HE] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Oertel_M/0/1/0/all/0/1">Micaela Oertel</a> (LUTH (UMR_8102)), <a href="http://arxiv.org/find/astro-ph/1/au:+Pascal_A/0/1/0/all/0/1">Aur&#xe9;lien Pascal</a> (LUTH (UMR_8102)), <a href="http://arxiv.org/find/astro-ph/1/au:+Mancini_M/0/1/0/all/0/1">Marco Mancini</a> (LUTH (UMR_8102)), <a href="http://arxiv.org/find/astro-ph/1/au:+Novak_J/0/1/0/all/0/1">Jerome Novak</a> (LUTH (UMR_8102)) Neutrinos play an important role in compact star astrophysics: neutrino-heating is one of the main ingredients in core-collapse supernovae, neutrino-matter interactions determine the composition of matter in binary neutron star mergers and have among others a strong impact on conditions for heavy element nucleosynthesis and neutron star cooling is dominated by neutrino emission except for very old stars. Many works in the last decades have shown that in dense matter mediumRead More →

Machine Learning meets the redshift evolution of the CMB Temperature. (arXiv:2002.12700v2 [astro-ph.CO] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Arjona_R/0/1/0/all/0/1">Rub&#xe9;n Arjona</a> We present a model independent and non-parametric reconstruction with a Machine Learning algorithm of the redshift evolution of the Cosmic Microwave Background (CMB) temperature from a wide redshift range $zin left[0,3right]$ without assuming any dark energy model, an adiabatic universe or photon number conservation. In particular we use the genetic algorithms which avoid the dependency on an initial prior or a cosmological fiducial model. Through our reconstruction we constrain new physics at late times. We provide novel and updated estimates on the $beta$ parameter from the parametrisation $text{T}(z)=text{T}_0(1+z)^{1-beta}$, theRead More →

Magnetospheric return-current-heated atmospheres of rotation-powered millisecond pulsars. (arXiv:2002.11427v3 [astro-ph.HE] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Salmi_T/0/1/0/all/0/1">Tuomo Salmi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Suleimanov_V/0/1/0/all/0/1">Valery F. Suleimanov</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Nattila_J/0/1/0/all/0/1">Joonas N&#xe4;ttil&#xe4;</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Poutanen_J/0/1/0/all/0/1">Juri Poutanen</a> We computed accurate atmosphere models of rotation-powered millisecond pulsars in which the polar caps of a neutron star (NS) are externally heated by magnetospheric return currents. The external ram pressure, energy losses, and stopping depth of the penetrating charged particles were computed self-consistently with the atmosphere model, instead of assuming a simplified deep-heated atmosphere in radiative equilibrium. We used exact Compton scattering formalism to model the properties of the emergent X-ray radiation. The deep-heating approximation was found to be valid only ifRead More →

FindBounce: package for multi-field bounce actions. (arXiv:2002.00881v2 [hep-ph] UPDATED) <a href="http://arxiv.org/find/hep-ph/1/au:+Guada_V/0/1/0/all/0/1">Victor Guada</a>, <a href="http://arxiv.org/find/hep-ph/1/au:+Nemevsek_M/0/1/0/all/0/1">Miha Nemev&#x161;ek</a>, <a href="http://arxiv.org/find/hep-ph/1/au:+Pintar_M/0/1/0/all/0/1">Matev&#x17e; Pintar</a> We are launching FindBounce, a Mathematica package for the evaluation of the Euclidean bounce action that enters the decay rate of metastable states in quantum and thermal field theories. It is based on the idea of polygonal bounces, which is a semi-analytical approach to solving the bounce equation by discretizing the potential into piecewise linear segments. This allows for a fast and robust evaluation of arbitrary potentials with specified precision and any number of scalar fields. Time cost grows linearly with the number of fields and/or theRead More →

Cosmic recombination history in light of EDGES measurements of the cosmic dawn 21-cm signal. (arXiv:2001.06497v2 [astro-ph.CO] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Datta_K/0/1/0/all/0/1">Kanan K. Datta</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kundu_A/0/1/0/all/0/1">Aritra Kundu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Paul_A/0/1/0/all/0/1">Ankit Paul</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bera_A/0/1/0/all/0/1">Ankita Bera</a> (Presidency University, Kolkata) The recent EDGES measurements of the global 21-cm signal from the cosmic dawn suggest that the kinetic temperature of the inter-galactic medium (IGM) might be significantly lower compared to its expected value. The colder IGM directly affects the hydrogen recombination of the universe during the cosmic dawn and dark ages by enhancing the rate of recombinations. Here, we study and quantify, the impact of the colder IGM scenario on the recombination historyRead More →

Open string QED meson description of the X17 particle and dark matter. (arXiv:2001.04864v5 [nucl-th] UPDATED) <a href="http://arxiv.org/find/nucl-th/1/au:+Wong_C/0/1/0/all/0/1">Cheuk-Yin Wong</a> As a quark and an antiquark cannot be isolated, the intrinsic motion of a composite $q bar q$ system in its lowest-energy states lies predominantly in 1+1 dimensions, as in an open string with the quark and the antiquark at its two ends. Accordingly, we study the lowest-energy states of an open string $qbar q$ system in QCD and QED in 1+1 dimensions. We show that $pi^0, eta$, and $eta’$ can be adequately described as open string $qbar q$ QCD mesons. By extrapolating into the $qbar q$Read More →

QCD axion and Neutrino induced by Hidden flavor structure. (arXiv:1912.09038v2 [hep-ph] UPDATED) <a href="http://arxiv.org/find/hep-ph/1/au:+Ahn_Y/0/1/0/all/0/1">Y. H. Ahn</a>, <a href="http://arxiv.org/find/hep-ph/1/au:+Bi_X/0/1/0/all/0/1">Xiaojun Bi</a> We study the reasonable requirements of two anomalous $U(1)$s in a flavored-axion framework for the anomaly cancellations of both $U(1)$-mixed gravity and $U(1)_Ytimes[U(1)]^2$ which in turn determine the $U(1)_Y$ charges where $U(1)_Y$ is the hypercharge gauge symmetry of the standard model. We argue that, with a flavor symmetry group, axion-induced topology in symmetry-broken phases plays crucial roles in describing how quarks and leptons are organized at a fundamental level and make deep connections with each other. A unified model, as an example, is then proposed inRead More →