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Related papers: Joshi--Malafarina--Narayan singularity in weak mag…

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We construct a generalized class of Joshi-Malafarina-Narayan (JMN) naked singularity spacetimes that arise as equilibrium end states of gravitational collapse with non-vanishing tangential pressure. The generalization introduces density…

General Relativity and Quantum Cosmology · Physics 2026-03-24 Jay Verma Trivedi , Pankaj S. Joshi

We analyze the causal structure of horizonless compact objects via the light-cone geometry and conformal compactification of the Joshi-Malafarina-Narayan (JMN-1) and Janis-Newman-Winicour (JNW) spacetimes. Penrose diagrams reveal that JMN-1…

General Relativity and Quantum Cosmology · Physics 2026-03-24 Bina Patel , Jahnvi Mistry , Ayush Bidlan , Parth Bambhaniya

In this paper, we investigate particle acceleration and high-energy collisions in the Joshi-Malafarina-Narayan (JMN-1) naked singularity, which, in the absence of an event horizon, allows infalling particles to turn back under specific…

General Relativity and Quantum Cosmology · Physics 2025-02-04 Kauntey Acharya , Parth Bambhaniya , Pankaj S. Joshi , Kshitij Pandey , Vishva Patel

It is a well known result that the effect of vacuum polarization in gravitational fields will lead to a non-minimal coupling between gravity and electromagnetism. We investigate this phenomenon further by considering the description of…

General Relativity and Quantum Cosmology · Physics 2019-01-10 Petar Pavlović , Marko Sossich

A series of tantalizing results led to the black hole uniqueness conjecture: isolated, realistic black holes should settle down to states characterized by their spin, mass and charge. I argue that generically real black holes will also…

General Relativity and Quantum Cosmology · Physics 2018-05-30 Adam D. Helfer

We study the effects of an external magnetic field, which is assumed to be uniform at infinity, on the marginally stable circular motion of charged particles in the equatorial plane of a rotating black hole. We show that the magnetic field…

General Relativity and Quantum Cosmology · Physics 2011-05-23 A. N. Aliev , N. Ozdemir

To model magnetic fields of compact objects we solve the Maxwell equations in the background of the exterior static Schwarzschild and slowly rotating Kerr space-times. We impose the boundary condition that the electromagnetic fields are to…

General Relativity and Quantum Cosmology · Physics 2025-04-15 Richard Kerner , Gideon Koekoek , Julia Schuring , Jan-Willem van Holten

Magnetic fields play a central role in black hole astrophysics, powering relativistic jets and other energetic phenomena. While near-horizon magnetic field is usually assumed to originate from the accretion flow, additional large-scale…

High Energy Astrophysical Phenomena · Physics 2026-01-29 Madina Zhakipova , Arman Tursunov , Saken Toktarbay , Martin Kološ

We extend the method of Simpson and Visser (SV) of regularising a black hole spacetime, to cases where the initial metric represents a globally naked singularity. We choose two particular geometries, the Janis-Newman-Winicour (JNW) metric…

General Relativity and Quantum Cosmology · Physics 2023-05-31 Kunal Pal , Kuntal Pal , Pratim Roy , Tapobrata Sarkar

Recent Event Horizon Telescope observations of M87* and Sgr A* strongly suggests the presence of supermassive black hole at their respective cores. In this work, we use the semi-analytic Radiatively Inefficient Accretion Flows (RIAF) model…

High Energy Astrophysical Phenomena · Physics 2024-02-08 Saurabh , Parth Bambhaniya , Pankaj S. Joshi

Interacting massive spin-1 fields have been widely used in cosmology and particle physics. We obtain a new condition on the validity of the classical limit of these theories related to the non-trivial constraints that exist for vector field…

High Energy Physics - Theory · Physics 2022-10-19 Zong-Gang Mou , Hong-Yi Zhang

Magnetic fields have been found to have an inherent capability of acting against gravity. An important question posed in the literature is whether presence of a magnetic field can alter the dynamics of a gravitational collapse and prevent…

General Relativity and Quantum Cosmology · Physics 2022-08-30 Shibendu Gupta Choudhury

In the mean field approximation of the relativistic $\sigma$-$\omega$-$\rho$ model, the magnetic fields are incorporated, and its influence on the properties of n-p-e neutron star matter are studied. When the strength of the magnetic field…

Astrophysics · Physics 2008-11-26 W. Chen , P. Q. Zhang , L. G. Liu

The performance characteristics of magnetic nanoparticles towards application, e.g. in medicine, imaging, or as sensors, is directly determined by their magnetization relaxation and total magnetic moment. In the commonly assumed picture,…

We obtain a family of exact solutions describing magnetized black holes in an external gravitational field. Locally the solutions can be interpreted as representing the near-horizon region of a black hole, which interacts with a surrounding…

General Relativity and Quantum Cosmology · Physics 2017-07-19 Jutta Kunz , Petya Nedkova , Stoytcho Yazadjiev

Using the Grad-Shafranov equation, we consider a new analytical model of the black hole magnetosphere based on the assumption that the magnetic field is radial near the horizon and uniform (cylindrical) in the jet region. Within this model,…

High Energy Astrophysical Phenomena · Physics 2013-03-12 V. S. Beskin , A. A. Zheltoukhov

We derive the form of the magnetic stress tensor in a completely general, stationary magnetic medium, with an arbitrary magnetization field $\vec M(\vec r)$ and free current density $\vec j(\vec r)$. We start with the magnetic force density…

Astrophysics · Physics 2007-05-23 Olivier Espinosa , Andreas Reisenegger

The exact superposition of a central static black hole with surrounding thin disk in presence of a magnetic field is investigated. We consider two models of disk, one of infinite extension based on a Kuzmin-Chazy-Curzon metric and other…

General Relativity and Quantum Cosmology · Physics 2013-12-09 Antonio C. Gutiérrez-Piñeres , Gonzalo García-Reyes , Guillermo A. González

In this work, we have investigated the outcome of gravitational collapse in Husain space-time in the presence of electro-magnetic and a scalar field with potential. In order to study the nature of the singularity, global behavior of radial…

General Relativity and Quantum Cosmology · Physics 2012-03-12 Ujjal Debnath , Prabir Rudra , Ritabrata Biswas

In the framework of the dynamical Chern-Simons gravity, we study the scalar field perturbations of the Reissner-Nordstr\"{o}m-Melvin spacetime, which describes a charged black hole permeated by a uniform magnetic field. In the presence of…

General Relativity and Quantum Cosmology · Physics 2023-02-02 Shao-Jun Zhang , Bin Wang , Eleftherios Papantonopoulos , Anzhong Wang
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