284 citations · 1.9k across the 32 of their papers we have counts for
32 papers
General relativistic limit of f(R) gravity in the horizon scale of black hole
Pranjali Bhattacharjee, Sanjeev Kalita, Debojit Paul +1
The environment of the Galactic Centre (GC) black hole, Sgr A* gives us new opportunities to test black hole physics and deviation from General Relativity. In this analytical study…
Homogeneous spacetime with shear viscosity
Inyong Cho, Rajibul Shaikh
We study the homogeneous and anisotropic evolution of Bianchi type-I spacetime driven by perfect fluid with shear viscosity. We obtain exact solutions by considering the simplest f…
A rotating modified JNW spacetime as a Kerr black hole mimicker
Kunal Pal, Kuntal Pal, Rajibul Shaikh +1
The Event Horizon Telescope has recently observed the images and shadows of the compact objects M87 and Sgr A at the centres of the galaxies Messier 87 and Milky Way. This…
Perfect fluid with shear viscosity and spacetime evolution
Inyong Cho, Rajibul Shaikh
We investigate the anisotropic evolution of spacetime driven by perfect fluid with off-diagonal shear-viscosity components. We consider the simplest form of the equation of state f…
Testing black hole mimickers with the Event Horizon Telescope image of Sagittarius A
Rajibul Shaikh
The Event Horizon Telescope (EHT) has recently observed the image and shadow of the supermassive compact object Sagittarius A (Sgr A). According to the EHT collaboration, t…
Shadows in conformally related gravity theories
Kunal Pal, Kuntal Pal, Rajibul Shaikh +1
Null geodesics are invariant under a conformal transformation, and thus it might seem natural to assume that the observables corresponding to the shadow of a space-time are also co…
Thin accretion disks around traversable wormholes
Farook Rahaman, Tuhina Manna, Rajibul Shaikh +3
In this paper, we aim to investigate various physical properties and characteristics of radiation emerging from the surface of accretion disks, in a rotating traversable axially sy…
Shadows of Lorentzian traversable wormholes
Farook Rahaman, Ksh. Newton Singh, Rajibul Shaikh +2
The prospect of identifying wormholes by investigating the shadows of wormholes constitute a foremost source of insight into the evolution of compact objects and it is one of the e…
Shadows and thin accretion disk images of the -metric
Rajibul Shaikh, Suvankar Paul, Pritam Banerjee +1
The -metric is a static, axially-symmetric singular solution of the vacuum Einstein's equations without an event horizon. This is a two-parameter family of solutions, generic va…
A stellar constraint on Eddington-inspired Born-Infeld gravity from cataclysmic variable binaries
Pritam Banerjee, Debojyoti Garain, Suvankar Paul +2
Eddington-inspired Born-Infeld gravity is an important modification of Einstein's general relativity, which can give rise to non-singular cosmologies at the classical level, and av…
Constraining alternatives to the Kerr black hole
Rajibul Shaikh, Kunal Pal, Kuntal Pal +1
The recent observation of the shadow of the supermassive compact object M87 by the Event Horizon Telescope (EHT) collaboration has opened up a new window to probe the strong gr…
Shadow of nulllike and timelike naked singularities without photon spheres
Dipanjan Dey, Rajibul Shaikh, Pankaj S. Joshi
In this paper, we derive general conditions for a shadow to occur, without a photon sphere in a spacetime, caused by central nulllike or timelike naked singularities. Using these c…
Constraining modified gravity from tidal phenomena in binary stars
Pritam Banerjee, Debojyoti Garain, Suvankar Paul +2
In beyond-Horndeski theories of gravity, the Vainshtein screening mechanism might only be partially effective inside stellar objects. This results in a modification of the pressure…
Perihelion Precession and Shadows near Blackholes and Naked Singularities
Dipanjan Dey, Rajibul Shaikh, Pankaj S. Joshi
It is now known that, apart from black holes, some naked singularities can also cast shadows which provide their possible observable signatures. We examine the relevant question he…
Tidal disruption near black holes and their mimickers
Pritam Banerjee, Suvankar Paul, Rajibul Shaikh +1
Black holes and wormholes are solutions of Einstein's field equations, both of which, from afar, look like a central mass. We show here that although at large distances both behave…
Observational signatures of wormholes with thin accretion disks
Suvankar Paul, Rajibul Shaikh, Pritam Banerjee +1
We numerically construct images of thin accretion disks in rotating wormhole backgrounds, for the Kerr-like and the Teo class of wormholes. Our construction is illustrated by two m…
Can we distinguish black holes from naked singularities by the images of their accretion disks?
Rajibul Shaikh, Pankaj S. Joshi
We study here images of thin accretion disks around black holes and two classes of naked singularity spacetimes and compare these scenarios. The naked singularity models which have…
Strong gravitational lensing by wormholes
Rajibul Shaikh, Pritam Banerjee, Suvankar Paul +1
We study strong gravitational lensing by a class of static wormhole geometries. Analytical approaches to the same are developed, and the results differ substantially from strong le…
Black hole shadow in a general rotating spacetime obtained through Newman-Janis algorithm
Rajibul Shaikh
The Newman-Janis (NJ) algorithm has been extensively used in the literature to generate rotating black hole solutions from nonrotating seed spacetimes. In this work, we show, using…
Analytical approach to strong gravitational lensing from ultracompact objects
Rajibul Shaikh, Pritam Banerjee, Suvankar Paul +1
Strong gravitational lensing from black holes results in the formation of relativistic images, in particular, relativistic Einstein rings. For objects with event horizons, the radi…
Tidal effects away from the equatorial plane in Kerr backgrounds
Pritam Banerjee, Suvankar Paul, Rajibul Shaikh +1
We study tidal effects on self-gravitating Newtonian stars rotating around a Kerr black hole in stable circular orbits away from the equatorial plane. Such cases are exemplified by…
A novel gravitational lensing feature by wormholes
Rajibul Shaikh, Pritam Banerjee, Suvankar Paul +1
Horizonless compact objects with light rings (or photon spheres) are becoming increasingly popular in recent years for several reasons. In this paper, we show that a horizonless ob…
Overcharging black holes and cosmic censorship in Eddington-inspired Born-Infeld gravity
Soumya Jana, Rajibul Shaikh, Sudipta Sarkar
The Eddington-inspired Born-Infeld (EiBI) gravity is a modification of the theory of general relativity inspired by the nonlinear Born-Infeld electrodynamics. The theory is describ…
Wormholes with nonexotic matter in Born-Infeld gravity
Rajibul Shaikh
We show that, in contrast to general relativity, in Eddington-inspired Born-Infeld gravity (EiBI), a violation of the null convergence condition does not necessarily lead to a viol…