RAS_WEB (Page 4,425)

Neutrino nucleosynthesis: An overview. (arXiv:1901.03741v1 [astro-ph.HE]) <a href="http://arxiv.org/find/astro-ph/1/au:+Langanke_K/0/1/0/all/0/1">Karlheinz Langanke</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Martinez_Pinedo_G/0/1/0/all/0/1">Gabriel Martinez-Pinedo</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sieverding_A/0/1/0/all/0/1">Andre Sieverding</a> Neutrinos produced during a supernova explosion induce reactions on abundant nuclei in the outer stellar shells and contribute in this way to the synthesis of the elements in the Universe. This neutrino nucleosynthesis process has been identified as an important contributor to the origin of $^7$Li, $^{11}$B,$^{19}$F, $^{138}$La, and $^{180}$Ta, but also to the long-lived radionuclides $^{22}$Na and $^{26}$Al, which are both key isotopes for $gamma$-ray astronomy. The manuscript summarizes the recent progress achieved in simulations of neutrino nucleosynthesis. Neutrinos produced during a supernova explosion induce reactions on abundant nucleiRead More →

Ion Charge States in a Time-Dependent Wave-Turbulence-Driven Model of the Solar Wind. (arXiv:1901.03748v1 [astro-ph.SR]) <a href="http://arxiv.org/find/astro-ph/1/au:+Lionello_R/0/1/0/all/0/1">Roberto Lionello</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Downs_C/0/1/0/all/0/1">Cooper Downs</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Linker_J/0/1/0/all/0/1">Jon A. Linker</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Mikic_Z/0/1/0/all/0/1">Zoran Miki&#x107;</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Raymond_J/0/1/0/all/0/1">John Raymond</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Shen_C/0/1/0/all/0/1">Chengcai Shen</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Velli_M/0/1/0/all/0/1">Marco Velli</a> Ion fractional charge states, measured in situ in the heliosphere, depend on the properties of the plasma in the inner corona. As the ions travel outward in the solar wind and the electron density drops, the charge states remain essentially unaltered or “frozen in”. Thus they can provide a powerful constraint on heating models of the corona and acceleration of the solar wind. We have implemented non-equilibrium ionization calculationsRead More →

Radio Frequency Timing Analysis of the Compact Jet in the Black Hole X-ray Binary Cygnus X-1. (arXiv:1901.03751v1 [astro-ph.HE]) <a href="http://arxiv.org/find/astro-ph/1/au:+Tetarenko_A/0/1/0/all/0/1">A.J. Tetarenko</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Casella_P/0/1/0/all/0/1">P. Casella</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Miller_Jones_J/0/1/0/all/0/1">J.C.A. Miller-Jones</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sivakoff_G/0/1/0/all/0/1">G.R. Sivakoff</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Tetarenko_B/0/1/0/all/0/1">B.E. Tetarenko</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Maccarone_T/0/1/0/all/0/1">T.J. Maccarone</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gandhi_P/0/1/0/all/0/1">P. Gandhi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Eikenberry_S/0/1/0/all/0/1">S. Eikenberry</a> We present simultaneous multi-band radio and X-ray observations of the black hole X-ray binary Cygnus X-1, taken with the Karl G. Jansky Very Large Array and the Nuclear Spectroscopic Telescope Array. With these data, we detect clear flux variability consistent with emission from a variable compact jet. To probe how the variability signal propagates down the jet flow, we perform detailed timing analysesRead More →

ATLASGAL — Molecular fingerprints of a sample of massive star forming clumps. (arXiv:1901.03759v1 [astro-ph.GA]) <a href="http://arxiv.org/find/astro-ph/1/au:+Urquhart_J/0/1/0/all/0/1">J. S. Urquhart</a> (1,2), <a href="http://arxiv.org/find/astro-ph/1/au:+Figura_C/0/1/0/all/0/1">C. Figura</a> (3), <a href="http://arxiv.org/find/astro-ph/1/au:+Wyrowski_F/0/1/0/all/0/1">F. Wyrowski</a> (2), <a href="http://arxiv.org/find/astro-ph/1/au:+Giannetti_A/0/1/0/all/0/1">A. Giannetti</a> (4,2), <a href="http://arxiv.org/find/astro-ph/1/au:+Kim_W/0/1/0/all/0/1">W.-J. Kim</a> (2), <a href="http://arxiv.org/find/astro-ph/1/au:+Wienen_M/0/1/0/all/0/1">M. Wienen</a> (2), <a href="http://arxiv.org/find/astro-ph/1/au:+Leurini_S/0/1/0/all/0/1">S. Leurini</a> (5,2), <a href="http://arxiv.org/find/astro-ph/1/au:+Pillai_T/0/1/0/all/0/1">T. Pillai</a> (2), <a href="http://arxiv.org/find/astro-ph/1/au:+Csengeri_T/0/1/0/all/0/1">T. Csengeri</a> (2), <a href="http://arxiv.org/find/astro-ph/1/au:+Gibson_S/0/1/0/all/0/1">S. J. Gibson</a> (1), <a href="http://arxiv.org/find/astro-ph/1/au:+Menten_K/0/1/0/all/0/1">K. Menten</a> (2), <a href="http://arxiv.org/find/astro-ph/1/au:+Moore_T/0/1/0/all/0/1">T. J. T. Moore</a> (6), <a href="http://arxiv.org/find/astro-ph/1/au:+Thompson_M/0/1/0/all/0/1">M. A. Thompson</a> (7), ((1) University of Kent, (2) MPIfR, (3) Wartburg College, (4) INAF-Bologna, (5) INAF-Selargius, (6) LJMU, (7) University of Hertfordshire) We have conducted a 3-mm molecular-line survey towards 570 high-mass star-forming clumps, using the MopraRead More →

Convolution Lagrangian Perturbation Theory for biased tracers beyond general relativity. (arXiv:1901.03763v1 [astro-ph.CO]) <a href="http://arxiv.org/find/astro-ph/1/au:+Valogiannis_G/0/1/0/all/0/1">Georgios Valogiannis</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bean_R/0/1/0/all/0/1">Rachel Bean</a> We extend the Convolution Lagrangian Perturbation Theory (CLPT) resummation formalism to analytically predict real and Fourier space two-point statistics for biased tracers in f(R) Hu-Sawicki and the nDGP braneworld modified gravity theories and compare the CLPT performance against predictions from Standard Perturbation Theory (SPT) and Lagrangian Resummation Theory. We show that the novel physics of gravitational collapse in scalar tensor theories with the chameleon or the Vainshtein screening mechanism, including sensitivity to the environment, can be effectively factored into CLPT with bias parameters analytically predicted through theRead More →

Towards More Reliable Analytic Thermochemical-equilibrium Abundances. (arXiv:1901.03764v1 [astro-ph.EP]) <a href="http://arxiv.org/find/astro-ph/1/au:+Cubillos_P/0/1/0/all/0/1">Patricio Cubillos</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Blecic_J/0/1/0/all/0/1">Jasmina Blecic</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Dobbs_Dixon_I/0/1/0/all/0/1">Ian Dobbs-Dixon</a> Heng & Tsai (2016) developed an analytic framework to obtain thermochemical-equilibrium abundances for H$_{2}$O, CO, CO$_2$, CH$_4$, C$_{2}$H$_{2}$, C$_{2}$H$_{4}$, HCN, NH$_3$, and N$_2$ for a system with known temperature, pressure, and elemental abundances (hydrogen, carbon, nitrogen, and oxygen). However, the implementation of their approach can become numerically unstable under certain circumstances, leading to inaccurate solutions (e.g., ${rm C/O} ge 1$ atmospheres at low pressures). Building up on their approach, we identified the conditions that prompt inaccurate solutions, and developed a new framework to avoid them, providing a reliableRead More →

Searching for the Donor Stars of ULX Pulsars. (arXiv:1901.03776v1 [astro-ph.HE]) <a href="http://arxiv.org/find/astro-ph/1/au:+Heida_M/0/1/0/all/0/1">M. Heida</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Harrison_F/0/1/0/all/0/1">F.A. Harrison</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Brightman_M/0/1/0/all/0/1">M. Brightman</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Furst_F/0/1/0/all/0/1">F. F&#xfc;rst</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Stern_D/0/1/0/all/0/1">D. Stern</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Walton_D/0/1/0/all/0/1">D.J. Walton</a> We report on our search for the optical counterparts of two ultraluminous X-ray pulsars with known orbital periods, M82 X-2 and NGC 5907 X-1, in new and archival HST observations, in an effort to characterize the donor stars in these systems. We detect five near-infrared sources consistent with the position of M82 X-2 that are too bright to be single stars. We also detect seven sources in the WFC3/UVIS F336W image whose photometry matches that of 10-15Read More →

GW170817 implications on the frequency and damping time of f-mode oscillations of neutron stars. (arXiv:1901.03779v1 [gr-qc]) <a href="http://arxiv.org/find/gr-qc/1/au:+Wen_D/0/1/0/all/0/1">De-Hua Wen</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Li_B/0/1/0/all/0/1">Bao-An Li</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Chen_H/0/1/0/all/0/1">Hou-Yuan Chen</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Zhang_N/0/1/0/all/0/1">Nai-Bo Zhang</a> Within a minimum model for neutron stars consisting of nucleons, electrons and muons at $beta$-equilibrium using about a dozen Equation of States (EOSs) from microscopic nuclear many-body theories and 40,000 EOSs randomly generated using an explicitly isospin-dependent parametric EOS model for high-density neutron-rich nucleonic matter within its currently known uncertainty range, we study correlations among the f-mode frequency, its damping time and the tidal deformability as well as the compactness of neutron stars. Except for quark stars,Read More →

Osaka Feedback Model: Isolated Disk Galaxy Simulations. (arXiv:1901.03815v1 [astro-ph.GA]) <a href="http://arxiv.org/find/astro-ph/1/au:+Shimizu_I/0/1/0/all/0/1">Ikkoh Shimizu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Todoroki_K/0/1/0/all/0/1">Keita Todoroki</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Yajima_H/0/1/0/all/0/1">Hidenobu Yajima</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Nagamine_K/0/1/0/all/0/1">Kentaro Nagamine</a> We study various implementations of supernova feedback model and present the results of our `Osaka feedback model’ using isolated galaxy simulations performed by the smoothed particle hydrodynamics (SPH) code {small GADGET-3}. Our model is a modified version of Stinson et al.’s work, and we newly add the momentum kick for SN feedback rather than only thermal feedback. We incorporate the physical properties of SN remnants from the results of Chevalier and McKee & Ostriker, such as the effective radius of SN bubble and theRead More →

Strong Evidence that the Galactic Bulge is Shining in Gamma Rays. (arXiv:1901.03822v1 [astro-ph.HE]) <a href="http://arxiv.org/find/astro-ph/1/au:+Macias_O/0/1/0/all/0/1">Oscar Macias</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Horiuchi_S/0/1/0/all/0/1">Shunsaku Horiuchi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kaplinghat_M/0/1/0/all/0/1">Manoj Kaplinghat</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gordon_C/0/1/0/all/0/1">Chris Gordon</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Crocker_R/0/1/0/all/0/1">Roland M. Crocker</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Nataf_D/0/1/0/all/0/1">David M. Nataf</a> There is growing evidence that the Galactic Center Excess identified in the $textit{Fermi}$-LAT gamma-ray data arises from a population of faint astrophysical sources. We provide compelling supporting evidence by showing that the morphology of the excess traces the stellar over-density of the Galactic bulge. By adopting a template of the bulge stars obtained from a triaxial 3D fit to the diffuse near-infrared emission, we show that it is detected at high significance.Read More →

Study of Lithium Rich Giants with the GALAH Spectroscopic Survey. (arXiv:1901.03832v1 [astro-ph.SR]) <a href="http://arxiv.org/find/astro-ph/1/au:+Deepak/0/1/0/all/0/1">Deepak</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Reddy_B/0/1/0/all/0/1">Bacham Eswar Reddy</a> In this article, we speculate on the possible mechanisms for Li enhancement origin in RGB stars based on a large data set of around 340,299 stars collected from the GALAH survey combined with the Gaia astrometry. Data has 51,982 low mass (M$leq$ 2M$_{odot}$) RGB stars with reliable atmospheric parameters. The data set shows a well populated RGB with well-defined luminosity bump and red clump with significant number of stars at each of these two key phases. We found 335 new Li-rich RGB stars with Li abundance, A(Li)Read More →

Physical properties of the X-ray gas as a dynamical diagnosis for galaxy clusters. (arXiv:1901.03851v1 [astro-ph.GA]) <a href="http://arxiv.org/find/astro-ph/1/au:+Lagana_T/0/1/0/all/0/1">T. F. Lagan&#xe1;</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Durret_F/0/1/0/all/0/1">F. Durret</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lopes_P/0/1/0/all/0/1">P. A. A. Lopes</a> We analysed XMM-{it Newton} EPIC data for 53 galaxy clusters. Through 2D spectral maps, we provide the most detailed and extended view of the spatial distribution of temperature (kT), pressure (P), entropy (S) and metallicity (Z) of galaxy clusters to date with the aim of correlating the dynamical state of the system to six cool-core diagnoses from the literature. With the objective of building 2D maps and resolving structures in kT, P, S and Z, we divide theRead More →

The corona contracts in a black-hole transient. (arXiv:1901.03877v1 [astro-ph.HE]) <a href="http://arxiv.org/find/astro-ph/1/au:+Kara_E/0/1/0/all/0/1">E. Kara</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Steiner_J/0/1/0/all/0/1">J. F. Steiner</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Fabian_A/0/1/0/all/0/1">A. C. Fabian</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cackett_E/0/1/0/all/0/1">E. M. Cackett</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Uttley_P/0/1/0/all/0/1">P. Uttley</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Remillard_R/0/1/0/all/0/1">R. A. Remillard</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gendreau_K/0/1/0/all/0/1">K. C. Gendreau</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Arzoumanian_Z/0/1/0/all/0/1">Z. Arzoumanian</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Altamirano_D/0/1/0/all/0/1">D. Altamirano</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Eikenberry_S/0/1/0/all/0/1">S. Eikenberry</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Enoto_T/0/1/0/all/0/1">T. Enoto</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Homan_J/0/1/0/all/0/1">J. Homan</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Neilsen_J/0/1/0/all/0/1">J. Neilsen</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Stevens_A/0/1/0/all/0/1">A. L. Stevens</a> The geometry of the accretion flow around stellar-mass black holes can change on timescales of days to months. When a black hole emerges from quiescence (that is, it “turns on” after accreting material from its companion) it has a very hard (high-energy) X-ray spectrum produced by a hotRead More →

Exploring the sensitivity of gravitational wave detectors to neutron star physics. (arXiv:1901.03885v1 [astro-ph.IM]) <a href="http://arxiv.org/find/astro-ph/1/au:+Martynov_D/0/1/0/all/0/1">Denis Martynov</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Miao_H/0/1/0/all/0/1">Haixing Miao</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Yang_H/0/1/0/all/0/1">Huan Yang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Vivanco_F/0/1/0/all/0/1">Francisco Hernandez Vivanco</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Thrane_E/0/1/0/all/0/1">Eric Thrane</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Smith_R/0/1/0/all/0/1">Rory Smith</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lasky_P/0/1/0/all/0/1">Paul Lasky</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+East_W/0/1/0/all/0/1">William E. East</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Adhikari_R/0/1/0/all/0/1">Rana Adhikari</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bauswein_A/0/1/0/all/0/1">Andreas Bauswein</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Brooks_A/0/1/0/all/0/1">Aidan Brooks</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Chen_Y/0/1/0/all/0/1">Yanbei Chen</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Corbitt_T/0/1/0/all/0/1">Thomas Corbitt</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Corbitt_T/0/1/0/all/0/1">Thomas Corbitt</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Grote_H/0/1/0/all/0/1">Hartmut Grote</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Levin_Y/0/1/0/all/0/1">Yuri Levin</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Zhao_C/0/1/0/all/0/1">Chunnong Zhao</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Vecchio_A/0/1/0/all/0/1">Alberto Vecchio</a> The physics of neutron stars can be studied with gravitational waves emitted from coalescing binary systems. Tidal effects become significant during the last few orbits and can be visible in the gravitational-wave spectrum above 500 Hz.Read More →

Quantifying the Influence of Key Physical Processes on the Formation of Emission Lines Observed by IRIS: I. Non-Equilibrium Ionization and Density-Dependent Rates. (arXiv:1901.03935v1 [astro-ph.SR]) <a href="http://arxiv.org/find/astro-ph/1/au:+Bradshaw_S/0/1/0/all/0/1">Stephen J. Bradshaw</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Testa_P/0/1/0/all/0/1">Paola Testa</a> In the work described here we investigate atomic processes leading to the formation of emission lines within the IRIS wavelength range at temperatures near $10^5$~K. We focus on (1) non-equilibrium and (2) density-dependent effects influencing the formation and radiative properties of S IV and O IV. These two effects have significant impacts on spectroscopic diagnostic measurements of quantities associated with the plasma that emission lines from S IV and O IV provide. We demonstrateRead More →

Roles of $^7$Be$(n,p)^7$Li resonances in big bang nucleosynthesis with time-dependent quark mass and Li reduction by a heavy quark mass. (arXiv:1901.03943v1 [astro-ph.CO]) <a href="http://arxiv.org/find/astro-ph/1/au:+Mori_K/0/1/0/all/0/1">Kanji Mori</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kusakabe_M/0/1/0/all/0/1">Motohiko Kusakabe</a> Big bang nucleosynthesis (BBN) has been used as a probe of beyond-standard physics in the early Universe, which includes a time-dependent quark mass m_q. We investigate effects of a quark mass variation delta m_q on the cross sections of the 7Be(n, p)7Li reaction and primordial light element abundances taking into account roles of 8Be resonances in the reaction during BBN. This resonant reaction has not been investigated although behaviors of low-lying resonances are not trivial. It isRead More →

Quantifying the uncertainties on spinodal instability in stellar matter through meta-modeling. (arXiv:1901.03959v1 [nucl-th]) <a href="http://arxiv.org/find/nucl-th/1/au:+Antic_S/0/1/0/all/0/1">Sofija Antic</a>, <a href="http://arxiv.org/find/nucl-th/1/au:+Chatterjee_D/0/1/0/all/0/1">Debarati Chatterjee</a>, <a href="http://arxiv.org/find/nucl-th/1/au:+Carreau_T/0/1/0/all/0/1">Thomas Carreau</a>, <a href="http://arxiv.org/find/nucl-th/1/au:+Gulminelli_F/0/1/0/all/0/1">Francesca Gulminelli</a> The influence of the uncertainties of the equation of state empirical parameters on the neutron stars crust-core phase transition is explored within a meta-modeling approach, in which the energy per particle is expanded as a Taylor series in density and asymmetry around the saturation point. The phase transition point is estimated from the intersection of the spinodal instability region for dynamical fluctuations with the chemical equilibrium curve. Special attention is paid to the inclusion of high-order parameters of the TaylorRead More →