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Gravitational waves astronomy allows us to study objects and events invisible in electromagnetic waves. It is crucial to validate the theories and models of the most mysterious and extreme matter in the Universe: the neutron stars. In…

High Energy Astrophysical Phenomena · Physics 2019-11-06 Magdalena Sieniawska , Michał Bejger

We consider the consequences of applying general relativity to the description of the dynamics of a galaxy, given the observed flattened rotation curves. The galaxy is modeled as a stationary axially symmetric pressure-free fluid. In spite…

Astrophysics · Physics 2010-10-27 F. I. Cooperstock , S. Tieu

We conjecture that space-like singularities are simply regions in which all available degrees of freedom are excited, and the system cycles randomly through generic quantum states in its Hilbert space. There is no simple geometric…

High Energy Physics - Theory · Physics 2007-05-23 T. Banks , W. Fischler

In this paper, we consider the gravitational collapse of generalized Vaidya space-time when the matter satisfies the equation of the state either $P=0$ or $P=-\alpha \rho$, where $0 < \alpha < 1$. We show that in the case when type I of…

General Relativity and Quantum Cosmology · Physics 2022-10-31 Vitalii Vertogradov

Observations show that about the 20% of the Universe is composed by invisible (dark) matter (DM), for which many candidates have been proposed. In particular, the anomalous behavior of rotational curves of galaxies (i.e. the flattening at…

Cosmology and Nongalactic Astrophysics · Physics 2009-05-19 Nicola Rossi

We investigate here the locally naked singularity formed due to a spherically symmetric inhomogeneous collapsing cloud having non-zero isotropic pressure, in terms of its strength. Sufficient condition provided by Clarke and Krolak for it…

General Relativity and Quantum Cosmology · Physics 2020-03-04 Karim Mosani , Dipanjan Dey , Pankaj S. Joshi

The general relativistic non--linear dynamics of a self--gravitating collisionless fluid with vanishing vorticity is studied in synchronous and comoving -- i.e. {\em Lagrangian} -- coordinates. Writing the equations in terms of the metric…

Astrophysics · Physics 2007-05-23 Sabino Matarrese

We model the gravitational collapse of heavy massive shells including its main quantum corrections. Among these corrections, quantum improvements coming from Quantum Einstein Gravity are taken into account, which provides us with an…

General Relativity and Quantum Cosmology · Physics 2015-06-19 R. Torres , F. Fayos

In our current best cosmological model, the vast majority of matter in the Universe is dark, consisting of yet undetected, non-baryonic particles that do not interact electro-magnetically. So far, the only significant evidence for dark…

Cosmology and Nongalactic Astrophysics · Physics 2020-09-09 Jenny Wagner

A class of solutions to Einstein field equations is studied, which represents gravitational collapse of thick spherical shells made of self-similar and shear-free fluid with heat flow. It is shown that such shells satisfy all the energy…

General Relativity and Quantum Cosmology · Physics 2009-11-07 R. Chan , M. F. A. da Silva , Jaime F. Villas da Rocha

We examine the gravitational lensing phenomenon caused by photon spheres in the Born-Infeld naked singularity spacetime, where gravity is coupled with Born-Infeld electrodynamics. Specifically, our focus lies on relativistic images…

General Relativity and Quantum Cosmology · Physics 2023-05-30 Yiqian Chen , Peng Wang , Houwen Wu , Haitang Yang

The critical collapse of a scalar field is a threshold solution of black hole formation, in which a naked singularity arises. We study here the curvature strength of this singularity using a numerical ansatz. The behavior of the Jacobi…

General Relativity and Quantum Cosmology · Physics 2020-11-16 Jun-Qi Guo , Lin Zhang , Yuewen Chen , Pankaj S. Joshi , Hongsheng Zhang

The orientation of non-spherical particles in the atmosphere, such as volcanic ash and ice crystals, influences their residence times, and the radiative properties of the atmosphere. Here, we demonstrate experimentally that the orientation…

Fluid Dynamics · Physics 2025-10-01 T. Bhowmick , J. Seesing , K. Gustavsson , J. Guettler , Y. Wang , A. Pumir , B. Mehlig , G. Bagheri

We investigate the occurrence and nature of naked singularities in the Szekeres space-times. These space-times represent irrotational dust. They do not have any Killing vectors and they are generalisations of the Tolman-Bondi-Lemaitre…

General Relativity and Quantum Cosmology · Physics 2009-10-28 Pankaj S. Joshi , Andrzej Krolak

The assumption of asymptotic flatness for isolated astrophysical bodies may be considered an approximation when one considers a cosmological context where a cosmological constant or vacuum energy is present. In this framework we study the…

General Relativity and Quantum Cosmology · Physics 2020-07-29 Bobir Toshmatov , Ozodbek Rahimov , Bobomurat Ahmedov , Daniele Malafarina

According to conventional modelling by general relativity the collapse of radially symmetric gravitating objects may end in a singular state. But by inclusion of potential energy into the energy tensor, which is required to guarantee global…

General Physics · Physics 2013-03-27 Ernst Fischer

Observational evidence of dark energy that makes the Universe nearly flat at the present epoch is very strong. We study the link between spatial continuity and dark energy. We assume that comoving space is a compact 3-manifold of constant…

Cosmology and Nongalactic Astrophysics · Physics 2009-12-02 Boudewijn F. Roukema , Vincent Blanloeil

Spherically symmetric inhomogeneous dust collapse has been studied in higher dimensional space-time and the factors responsible for the appearance of a naked singularity are analyzed in the region close to the centre for the marginally…

General Relativity and Quantum Cosmology · Physics 2009-11-07 Asit Banerjee , Ujjal Debnath , Subenoy Chakraborty

Repulsive gravity is a well known characteristic of naked singularities. In this work, we explore light surfaces and find new effects of repulsive gravity. We compare Kerr naked singularities with the corresponding black hole counterparts…

General Relativity and Quantum Cosmology · Physics 2022-03-23 Daniela Pugliese , Hernando Quevedo

This paper considers two-dimensional gravity solitary waves moving through a body of density stratified water lying below vacuum. The fluid domain is assumed to lie above an impenetrable flat ocean bed, while the interface between the water…

Analysis of PDEs · Mathematics 2021-07-30 Robin Ming Chen , Samuel Walsh , Miles H. Wheeler