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If the initial state of the inflaton field is taken to have a thermal distribution instead of the conventional zero particle vacuum state then the curvature power spectrum gets modified by a temperature dependent factor such that the…

High Energy Physics - Phenomenology · Physics 2008-11-26 Kaushik Bhattacharya , Subhendra Mohanty , Raghavan Rangarajan

We investigate the predicted present-day temperature profiles of the hot, X-ray emitting gas in galaxy clusters for two cosmological models - a current best-guess LCDM model and standard cold dark matter (SCDM). Our numerically-simulated…

Astrophysics · Physics 2008-11-26 C. Loken , M. L. Norman , E. Nelson , J. Burns , G. L. Bryan , P. Motl

Thermal convection in fluid layers heated from below are usually realized experimentally as well as treated theoretically with fixed boundaries on which conditions for the temperature and the velocity field are prescribed. The thermal and…

Fluid Dynamics · Physics 2011-02-08 R. D. Simitev , F. H. Busse

We study the collapse of a self-gravitating and radiating shell. Matter constituting the shell is quantized and the construction is viewed as a semiclassical model of possible black hole formation. It is shown that the shell internal…

General Relativity and Quantum Cosmology · Physics 2008-11-26 G. L. Alberghi , R. Casadio , G. P. Vacca , G. Venturi

It is shown that the existence of radiation-induced solitary waves in hot plasmas of accretion disks depends on the radial temperature profile.

Astrophysics · Physics 2007-05-23 Fedor V. Prigara

Recent observations show that the thermal X-ray spectra of many isolated neutron stars are featureless and in some cases (e.g., RX J1856.5-3754) well fit by a blackbody. Such a perfect blackbody spectrum is puzzling since radiative…

Astrophysics · Physics 2009-11-10 Matthew van Adelsberg , Dong Lai , Alexander Y. Potekhin , Phil Arras

Thanks to recent measurements of tidal deformability and radius, the nuclear equation of state and structure of neutron stars are now better understood. Here, we show that through resonant tidal excitations in a binary inspiral, the neutron…

High Energy Astrophysical Phenomena · Physics 2020-11-18 Zhen Pan , Zhenwei Lyu , Béatrice Bonga , Néstor Ortiz , Huan Yang

Recently 3D hydrodynamical simulations of stellar surface convection have become feasible thanks to advances in computer technology and efficient numerical algorithms. Available observational diagnostics indicate that these models are…

Astrophysics · Physics 2007-05-23 Martin Asplund , Remo Collet

In this paper, we consider the asymptotic profiles of zero points for the spatial variable of the solutions to the heat equation. By giving suitable conditions for the initial data, we prove the existence of zero points by extending the…

Analysis of PDEs · Mathematics 2023-05-25 Hiroshi Ishii

Recent observations have found several candidates for old warm neutron stars whose surface temperatures are above the prediction of the standard neutron star cooling scenario, and thus require some heating mechanism. Motivated by these…

High Energy Astrophysical Phenomena · Physics 2020-02-20 Keisuke Yanagi , Natsumi Nagata , Koichi Hamaguchi

We studied the formation of compact bosonic objects through a dissipationless cooling mechanism. Implications of the existence of this mechanism are discussed, including the abundance of bosonic stars in the universe, and the possibility of…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Edward Seidel , Wai-Mo Suen

Massive stars influence their surroundings through radiation, winds, and supernova explosions far out of proportion to their small numbers. However, the physical processes that initiate and govern the birth of massive stars remain poorly…

Astrophysics of Galaxies · Physics 2010-11-18 Thomas Peters , Ralf S. Klessen , Mordecai-Mark Mac Low , Robi Banerjee

Free cooling of a gas of inelastically colliding hard spheres represents a central paradigm of kinetic theory of granular gases. At zero gravity the temperature of a freely cooling homogeneous granular gas follows a power law in time. How…

Soft Condensed Matter · Physics 2009-11-11 Dmitri Volfson , Baruch Meerson , Lev S. Tsimring

We study thermal states of transiently accreting neutron stars (with mean accretion rates $\dot{M} \sim 10^{-14}-10^{-9}$ M$_\odot$ yr$^{-1}$) determined by the deep crustal heating of accreted matter sinking into stellar interiors. We…

Astrophysics · Physics 2014-10-13 D. G. Yakovlev , K. P. Levenfish , P. Haensel

Stars form by the gravitational collapse of interstellar gas. The thermodynamic response of the gas can be characterized by an effective equation of state. It determines how gas heats up or cools as it gets compressed, and hence plays a key…

Principally important for the description the physical processes in the collapsing stellar cores topics are surveyed. They are: the neutrino heat conduction theory, equation of state under the conditions of nuclear statistical equilibrium…

Solar and Stellar Astrophysics · Physics 2013-08-22 D. K. Nadyozhin , A. V. Yudin

In a previous paper, we modeled the oscillations of a thermally-supported (Bonnor-Ebert) sphere as non-radial, linear perturbations following a standard analysis developed for stellar pulsations. The predicted column density variations and…

Astrophysics · Physics 2009-11-13 Avery E. Broderick , Eric Keto , Charles J. Lada , Ramesh Narayan

A new solution is presented for the puzzling, observed universality of the exponential luminosity profiles, perpendicular to the disk plane of spiral and lenticular galaxies. It is shown that such exponential $z$-profiles result naturally…

Astrophysics · Physics 2007-05-23 A. Burkert , Y. Yoshii

In completely local settings, we establish that a dynamically evolving black hole horizon can be assigned a Hawking temperature. Moreover, we calculate the Hawking flux and show that the radius of the horizon shrinks.

General Relativity and Quantum Cosmology · Physics 2015-06-04 Ayan Chatterjee , Bhramar Chatterjee , Amit Ghosh

We investigate a simple model corresponding to particles driven in opposite directions and interacting via a repulsive potential. The particles move off-lattice on a periodic strip and are subject to random forces as well. We show that this…

Statistical Mechanics · Physics 2009-10-31 Dirk Helbing , Illes Farkas , Tamas Vicsek
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