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In the present work we study spherically symmetric gravitational collapse of a homogeneous perfect fluid in the context of Generalized Rastall Theory (GRT). In this modified version of the original {Rastall Gravity (RG)}, the coupling…

General Physics · Physics 2021-11-03 A. H. Ziaie , H. Moradpour , M. Mohammadi Sabet

Based on the effective dynamics in the $\bar \mu$ scheme of the spherical symmetry reduced model in the reduced phase space formulation of loop quantum gravity (LQG), we investigate the gravitational collapse of a homogeneous dust cloud,…

General Relativity and Quantum Cosmology · Physics 2023-03-08 Kristina Giesel , Muxin Han , Bao-Fei Li , Hongguang Liu , Parampreet Singh

We investigate the role of non-isothermality in gravitational collapse and protostellar accretion by explicitly including the effects of molecular radiative cooling, gas-dust energy transfer, and cosmic ray heating in models of spherical…

Astrophysics · Physics 2009-11-13 E. I. Vorobyov , Shantanu Basu

Based on modifications inspired from loop quantum gravity (LQG), spherically symmetric models have recently been explored to understand the resolution of classical singularities and the fate of the spacetime beyond. While such…

General Relativity and Quantum Cosmology · Physics 2023-08-23 Kristina Giesel , Hongguang Liu , Parampreet Singh , Stefan Andreas Weigl

A new cosmological model based on the de Sitter gauge theory (dSGT) is studied in this paper. By some transformations, we find, in the dust universe, the cosmological equations of dSGT could form an autonomous system. We conduct dynamics…

General Relativity and Quantum Cosmology · Physics 2011-11-09 Xi-Chen Ao , Xin-Zhou Li

We compare different examples of spherical accretion onto a gravitating mass. Limiting cases include the accretion of a collisionally dominated fluid and the accretion of collisionless particles. We derive expressions for the accretion rate…

Astrophysics · Physics 2009-11-11 Re'em Sari , Peter Goldreich

Semiclassical stochastic gravity is aimed at studying extended structure formation in the early universe. Rigorous developments in this area include the semiclassical noise and dissipation kernels which are obtained in terms of quantum…

General Relativity and Quantum Cosmology · Physics 2024-12-17 Seema Satin

We perform numerical simulations of clouds in the Galactic Centre (GC) engulfing the nuclear super-massive black hole and show that this mechanism leads to the formation of gaseous accretion discs with properties that are similar to the…

Astrophysics of Galaxies · Physics 2011-05-03 Christian Alig , Andreas Burkert , Peter H. Johansson , Marc Schartmann

This paper presents two interesting scaling laws, which relate some critical exponents in the critical behavior of spherically symmetric gravitational collapses. These scaling laws are independent of the details of gravity theory under…

General Relativity and Quantum Cosmology · Physics 2015-12-23 Rong-Gen Cai , Run-Qiu Yang

In broad astrophysical contexts of large-scale gravitational collapses and outflows and as a basis for various further astrophysical applications, we formulate and investigate a theoretical problem of self-similar MHD for a non-rotating…

Astrophysics · Physics 2009-09-29 Wei-Gang Wang , Yu-Qing Lou

In this paper, we explore a collapsing scenario in the background of energy-momentum squared gravity (EMSG). EMSG claims to have terms that originate from the quantum gravity effects mimicking loop quantum gravity. As a result, the…

General Relativity and Quantum Cosmology · Physics 2024-02-14 Prabir Rudra

Multidimensional magneto-hydrodynamical (MHD) simulations coupled with stochastic differential equations (SDEs) adapted to test particle acceleration and transport in complex astrophysical flows are presented. The numerical scheme allows…

Astrophysics · Physics 2009-11-07 F. Casse , A. Marcowith

We derive a semi-analytical extension of the spherical collapse model of structure formation that takes account of the effects of deviations from spherical symmetry and shell crossing which are important in the non-linear regime. Our model…

Astrophysics · Physics 2008-11-26 Douglas J. Shaw , David F. Mota

This work is devoted to the thermodynamics of gravitational clustering, a collective phenomenon with a great relevance in the $N$-body cosmological problem. We study a classical self-gravitating gas of identical non-relativistic particles…

Statistical Mechanics · Physics 2016-11-03 F. Tello-Ortiz , L. Velazquez

We describe a class of exactly soluble models for gravitational collapse in spherical symmetry obtained by patching dynamical spherically symmetric exterior spacetimes with cosmological interior spacetimes. These are generalizations of the…

General Relativity and Quantum Cosmology · Physics 2013-05-29 Benjamin K. Tippett , Viqar Husain

We investigate the dynamics of black hole critical collapse in the limit of a large number of spacetime dimensions, $D$. In particular, we study the spherical gravitational collapse of a massless, scale-invariant scalar field with…

High Energy Physics - Theory · Physics 2025-11-10 Craig R. Clark , Guilherme L. Pimentel

Extended filamentary H$\alpha$ emission nebulae are a striking feature of nearby galaxy clusters but the formation mechanism of the filaments, and the processes which shape their morphology remain unclear. We conduct an investigation into…

We present the results of numerical simulations of the spherically symmetric gravitational collapse of supermassive stars (SMS). The collapse is studied using a general relativistic hydrodynamics code. The coupled system of Einstein and…

Astrophysics · Physics 2009-11-06 Felix Linke , Jose A. Font , Hans-Thomas Janka , E. Mueller , Philippos Papadopoulos

We reconsider the widely held view that the Mannheim--Kazanas (MK) vacuum solution for a static, spherically-symmetric system in conformal gravity (CG) predicts flat rotation curves, such as those observed in galaxies, without the need for…

General Relativity and Quantum Cosmology · Physics 2021-09-13 Michael Hobson , Anthony Lasenby

We develop an algebraic equation to describe the collapse and possible bounce of dust in quantum-inspired gravity models with spherical symmetry from knowledge of the vacuum solution. Starting from a wide class of spherically symmetric…

General Relativity and Quantum Cosmology · Physics 2026-04-30 Douglas M. Gingrich