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We present the results of a series of calculations studying the collapse of molecular cloud cores performed using a three-dimensional smoothed particle hydr odynamics code with radiative transfer in the flux-limited diffusion approximation.…

Astrophysics · Physics 2009-11-13 Stuart C. Whitehouse , Matthew R. Bate

We study the quantum particle creation in a toy model of spherically symmetric gravitational collapse whose final product is not a black hole but a gravastar. Precedent studies revealed that even in the case of the gravitational collapse to…

General Relativity and Quantum Cosmology · Physics 2022-11-23 Ken-ichi Nakao , Kazumasa Okabayashi , Tomohiro Harada

We examine the role of space-time geometry in the non-adiabatic collapse of a star dissipating energy in the form of radial heat flow, studying its evolution under different initial conditions. The collapse of a star with interior…

General Relativity and Quantum Cosmology · Physics 2013-04-30 R. Sharma , R. Tikekar

We propose a new analytic model for the initial conditions of protostellar collapse in relatively isolated regions of star formation. The model is non-magnetic, and is based on a Plummer-like radial density profile as its initial condition.…

Astrophysics · Physics 2009-10-31 A. P. Whitworth , D. Ward-Thompson

The origin of the recently reported systematic bias in the spectroscopic temperature of galaxy clusters is investigated using cosmological hydrodynamical simulations. We find that the local inhomogeneities of the gas temperature and…

The classical Hamiltonian for a chargeless and massless particle in a very near horizon region is shown to be of the form $H\sim xp$ as long as radial motion is concerned. This is demonstrated explicitly for static spherically symmetric…

General Relativity and Quantum Cosmology · Physics 2020-08-06 Surojit Dalui , Bibhas Ranjan Majhi , Pankaj Mishra

We consider a scenario where the interior spacetime,described by a heat conducting fluid sphere is matched to a Vaidya metric in higher dimensions.Interestingly we get a class of solutions, where following heat radiation the boundary…

General Relativity and Quantum Cosmology · Physics 2009-11-10 A. banerjee , S. Chatterjee

In this paper a study of the accelerated expansion problem of the large scale universe is presented. To derive Friedmann like equations, describing the background dynamics of the recent universe we take into account, that it is possibile to…

General Relativity and Quantum Cosmology · Physics 2017-09-20 M. Khurshudyan , As. Khurshudyan

We analyse a simple model of the heat transfer to and from a small satellite orbiting round a solar system planet. Our approach considers the satellite isothermal, with external heat input from the environment and from internal energy…

Space Physics · Physics 2009-09-25 Jose Gaite , Angel Sanz-Andrés , Isabel Pérez-Grande

We compute the temperature profiles of accretion discs around rapidly rotating strange stars, using constant gravitational mass equilibrium sequences of these objects, considering the full effect of general relativity. Beyond a certain…

Astrophysics · Physics 2009-11-06 Sudip Bhattacharyya , Arun V. Thampan , Ignazio Bombaci

Aims: We aim to simulate radial profiles of molecular abundances and the gas temperature in cold and heavily shielded starless cores by combining chemical and radiative transfer models. Methods: A determination of the dust temperature in a…

Astrophysics of Galaxies · Physics 2015-06-05 O. Sipilä

Collapsing collisionless particle systems form gravitational bound halos with cuspy density profiles. Also hierarchical merging of these systems produce remnants with cuspy central density profiles. These results lead to the assumption of…

Astrophysics · Physics 2009-11-07 Marc Hemsendorf

By means of high-resolution N-body simulations we revisited the dissipationless collapse scenario for galaxy formation. We considered both single-component collapses and collapses of a cold stellar distribution in a live dark matter halo.…

Astrophysics · Physics 2009-11-11 C. Nipoti , P. Londrillo , L. Ciotti

Interested in the collapse of a radiating star, we study the temporal evolution of a fluid with heat flux and bulk viscosity, including anisotropic pressure. As a starting point, we adopt an initial configuration that satisfies the…

General Relativity and Quantum Cosmology · Physics 2018-11-27 L. S. M. Veneroni , M. F. A. da Silva

We investigate the role played by density inhomogeneities and dissipation on the final outcome of collapse of a self-gravitating sphere. By imposing a perturbative scheme on the thermodynamical variables and gravitational potentials we…

General Relativity and Quantum Cosmology · Physics 2021-02-12 Nolene F. Naidu , Robert S. Bogadi , Anand Kaisavelu , Megan Govender

We extend previous results on the reflection and transmission of self-gravitating dust shells across the apparent horizon during quantum dust collapse to non-marginally-bound dust collapse in arbitrary dimensions with a negative…

General Relativity and Quantum Cosmology · Physics 2013-01-31 Cenalo Vaz , Kinjalk Lochan

We calculate temperature profiles and X-ray spectra of accretion disks around rapidly rotating neutron stars considering the full effect of general relativity. Computed disk temperatures and luminosities are compared with the EXOSAT data to…

Astrophysics · Physics 2007-05-23 Sudip Bhattacharyya

Planetesimal formation models often invoke the gravitational collapse of pebble clouds to overcome various barriers to grain growth and propose processes to concentrate particles sufficiently to trigger this collapse. On the other hand, the…

Earth and Planetary Astrophysics · Physics 2024-12-11 P. Segretain , H. Méheut , M. Moreira , G. Lesur , C. Robert , J. Mauxion

We study the effects of finite stellar temperatures on the oscillations of superfluid neutron stars. The importance of these effects is illustrated with a simple example of a radially pulsating general relativistic star. Two main effects…

Solar and Stellar Astrophysics · Physics 2011-06-07 E. M. Kantor , M. E. Gusakov

We present an analytic description of the spherically symmetric gravitational collapse of radiatively cooling gas clouds, which illustrates the mechanism by which radiative cooling induces gravitational instability at a characteristic mass…

Astrophysics of Galaxies · Physics 2025-01-03 James Gurian , Boyuan Liu , Donghui Jeong , Takashi Hosokawa , Shingo Hirano , Naoki Yoshida