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Over the last years, the search of new regular black bounce solutions has drawn a lot of attentional over the international community working in gravitation. Indeed, in the era of gravitational waves detections out of binary mergers and of…

General Relativity and Quantum Cosmology · Physics 2025-01-08 G. Alencar , Albert Duran-Cabacés , Diego Rubiera-Garcia , Diego Sáez-Chillón Gómez

A global view is given upon the study of collapsing shear-free perfect fluid spheres with heat flow. We apply a compact formalism, which simplifies the isotropy condition and the condition for conformal flatness. This formalism also…

General Relativity and Quantum Cosmology · Physics 2012-06-08 B. V. Ivanov

In the framework of Simpson-Visser, the search for field sources that produce black-bounces in alternative gravity theories has remained unresolved. In this paper, the first in a series exploring sources for alternative theories of gravity,…

General Relativity and Quantum Cosmology · Physics 2025-08-27 G. Alencar , M. Nilton , Manuel E. Rodrigues , Marcos V. de S. Silva

We study the spherically symmetric collapse of a cloud of dust in VCDM, a class of gravitational theories with two local physical degrees of freedom. We find that the collapse corresponds to a particular foliation of the Oppenheimer-Snyder…

General Relativity and Quantum Cosmology · Physics 2023-03-22 Antonio De Felice , Kei-ichi Maeda , Shinji Mukohyama , Masroor C. Pookkillath

If due attention is given in formulating the basic equations for the Gamma-Ray Burst (GRB) phenomenon and in performing the corresponding quantitative analysis, GRBs open a main avenue of inquiring on totally new physical and astrophysical…

Astrophysics · Physics 2009-11-07 R. Ruffini , C. L. Bianco , P. Chardonnet , F. Fraschetti , L. Vitagliano , S. -S. Xue

Rapidly rotating black hole solutions in theories beyond general relativity play a key role in experimental gravity, as they allow us to compute observables in extreme spacetimes that deviate from the predictions of general relativity. Such…

General Relativity and Quantum Cosmology · Physics 2016-11-29 Robert McNees , Leo C. Stein , Nicolás Yunes

We present a class of conformally flat solutions of the Einstein's field equations for spherical systems undergoing gravitational collapse accompanied with radial heat flux. The interior space-time of the collapsing matter is chosen to be…

General Relativity and Quantum Cosmology · Physics 2017-11-20 Ranjan Sharma , Shyam Das , Ramesh Tikekar

It is shown, for the self-consistent system of scalar, electro-magnetic and gravitational fields in general relativity, that the equations of motion admit a special kind of solutions with spherical or cylindrical symmetry. For these…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Yu. P. Rybakov , B. Saha , G. N. Shikin

A class of spherical collapsing exact solutions with electromagnetic charge is derived. This class of solutions -- in general anisotropic -- contains however as a particular case the charged dust model already known in literature. Under…

General Relativity and Quantum Cosmology · Physics 2015-06-11 F. Cipolletta , R. Giambò

We focus on the classification of positive solutions to $(-\Delta)^s u=\frac{x_n^{\alpha}}{u^\gamma}$ in the half space with $\gamma>0$, subject to the Dirichlet condition. We show that when $-2s<\alpha<(\gamma-1)s$, all positive solutions…

Analysis of PDEs · Mathematics 2026-04-23 Yahong Guo , Chilin Zhang

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

The general metric for N-dimensional spherically symmetric and conformally flat spacetimes is given, and all the homogeneous and isotropic solutions for a perfect fluid with the equation of state $p = \alpha \rho$ are found. These solutions…

General Relativity and Quantum Cosmology · Physics 2009-10-31 J. F. Villas da Rocha , Anzhong Wang

We discuss black holes in an effective theory derived from a superstring model, which includes a dilaton field, a gauge field and the Gauss-Bonnet term. Assuming U(1) or SU(2) symmetry for the gauge field, we find four types of spherically…

General Relativity and Quantum Cosmology · Physics 2010-11-19 Takashi Torii , Hiroki Yajima , Kei-ichi Maeda

We study the collapse of spherical cold clouds beyond black hole formation to investigate the possibility of a bounce in the in-falling matter when a critical density or pressure is reached. As a first step, we analyse the pressureless…

General Relativity and Quantum Cosmology · Physics 2025-01-24 Swaraj Pradhan , Michael Gabler , Enrique Gaztañaga

We seek to obtain a new class of exact solutions of regular black holes in $f(T)$ Gravity with non-linear electrodynamics material content, with spherical symmetry in $4D$. The equations of motion provide the regaining of various solutions…

General Relativity and Quantum Cosmology · Physics 2015-11-02 Ednaldo L. B. Junior , Manuel E. Rodrigues , Mahouton J. S. Houndjo

We investigate gravitational collapse of thick shell of fluid in the isotropic homogeneous universe without radiation described by the Einstein gravity with cosmological constant. We construct analytic solutions of this kind interpolating…

General Relativity and Quantum Cosmology · Physics 2022-09-07 Shuichi Yokoyama

We study the spherical collapse of a perfect fluid with an equation of state $P=k\rho$ by full general relativistic numerical simulations. For $0<k\alt 0.036$, it has been known that there exists a general relativistic counterpart of the…

General Relativity and Quantum Cosmology · Physics 2009-11-07 Tomohiro Harada , Hideki Maeda

A general solution to the $D=2$ 1-loop beta functions equations including tachyonic back reaction on the metric is presented. Dynamical black hole (classical) solutions representing gravitational collapse of tachyons are constructed. A…

High Energy Physics - Theory · Physics 2009-12-30 J. G. Russo

This work is concerned with the study of explicit solutions for generalized coupled reaction-diffusion and Burgers-type systems with variable coefficients. Including nonlinear models with variable coefficients such as diffusive…

Mathematical Physics · Physics 2024-06-26 José M. Escorcia , Erwin Suazo

We consider the problem of critical gravitational collapse of a scalar field in 2+1 dimensions with spherical (circular) symmetry. After surveying all the analytic, continuously self-similar solutions and considering their global structure,…

General Relativity and Quantum Cosmology · Physics 2009-07-07 Eric W. Hirschmann , Anzhong Wang , Yumei Wu