arXiv subjects

Rehana Rahim

Publications and source records attributed to Rehana Rahim.

5 recordsLinked to original sources

arXiv2022

Particle dynamics in non-rotating Konoplya and Zhidenko black hole immersed in an external uniform magnetic field

In this paper, we investigate the dynamics of particles in the background of non-rotating Konoplya and Zhidenko black hole that is immersed in an external uniform magnetic field. The work involves circular motion of electric and magnetic particles and particle acceleration. First the motion of electric charged particles is considered. The effective potential, energy and angular momentum expressions are obtained along with their graphs. The analysis of ISCO shows that radii of ISCO decrease with magnetic interaction parameter. Motion of magnetically charged particles has also been studied.

gr-qc↗

arXiv2021

Particle dynamics and geometric optics in Chern-Simons black holes

In this paper we study the effects of the coupling constant of the Chern-Simons modified gravity on some physical properties of black holes. The Hawking mass is one of the proposed definitions of quasilocal mass. We find that, for slowly rotating Chern-Simons black holes, the Hawking mass is independent of the coupling constant. Next, we show the dependence on the centre of mass energy, for two neutral colliding particles, of coupling constant and the rotation parameter. We also investigate energy extraction through Penrose process and find that the energy gain and efficiency of the Penrose process are independent of this coupling constant. Rotation of the polarization vector is also studied for dependence on the Chern-Simons coupling constant.

gr-qc↗

arXiv2021

The non-Kerr black hole with acceleration

The no-hair theorem can be tested in the strong gravity regime by using the top-bottom approach and the bottom-top approach. The non-Kerr spacetime of the later approach is an ideal framework to do the tests in the region very close to the black holes. In this work, we propose a non-Kerr black hole metric (and its charged extension) that is accelerating as well. These new objects are studied for their basic properties and thermodynamics.

gr-qc↗

arXiv2019

Charging the Johannsen-Psaltis spacetime

In this paper we develop the charged version of the spacetime proposed by Johannsen and Psaltis. Rotation is introduced in the deformed Reissner-Nordström spacetime by complex coordinate transformation. The event horizon and Killing horizon are studied. Killing horizons are represented graphically also. The analysis of the determinant of the metric shows that the spacetime does not have Lorentz violating regions. Similarly, from the study of the closed time-like curves, we see that no such curves exist outside the central body. Expressions for the energy and angular momentum for a particle on the equatorial plane are determined. Location of the circular photon orbits and innermost stable circular orbits is also computed.

gr-qc↗

arXiv2019

The marginally trapped surfaces in spheroidal spacetimes

We study the location of marginally trapped surfaces in space-times resulting from an axial deformation of static isotropic systems, and show that the Misner-Sharp mass evaluated on the corresponding undeformed spherically symmetric space provides the correct gravitational radius to locate the spheroidal horizon.

gr-qc↗