98 citations · 693 across the 35 of their papers we have counts for
36 papers
Tidal forces in collapsing compact objects
Ashok B. Joshi, Dipanjan Dey, Pankaj S. Joshi +1
In this work, we investigate tidal forces in the Lemaitre-Tolman-Bondi (LTB) metric, focusing on both hidden and locally visible singularities. We discuss the strength of these sin…
A bonafide model of structure formation from gravitational collapse
Koushiki, Dipanjan Dey, Pankaj S. Joshi
This paper explores the cosmological implications of a scalar field with a specific potential, crucial for achieving the final equilibrium state of gravitational collapse. We consi…
Equilibrium states from gravitational collapse of minimally coupled scalar field with non-zero potential
Dipanjan Dey, Koushiki, Pankaj S. Joshi
We study the model of spherically symmetric and spatially homogeneous gravitational collapse of a minimally coupled scalar field. Our study focuses on obtaining the scalar field po…
Gravitational collapse of matter in the presence of Quintessence and Phantom-like scalar fields
Priyanka Saha, Dipanjan Dey, Kaushik Bhattacharya
In this work, we propose a model of the gravitational collapse of dark matter in the presence of quintessence or phantom-like scalar fields. Our treatment is based on the principle…
Tidal forces in the Simpson-Visser black-bounce and wormhole spacetimes
Dhruv Arora, Parth Bambhaniya, Dipanjan Dey +1
The concept of regular black holes has gained attention in recent years, especially in the context of quantum gravity theories. In these theories, the existence of singularities is…
The equilibrium condition in gravitational collapse and its application to a cosmological scenario
Dipanjan Dey, N. T. Layden, A. A. Coley +1
We discuss the equilibrium conditions of the gravitational collapse of a spherically symmetric matter cloud. We analyze the spinor structure of a general collapsing space-time and…
Observational aspects of a class of Dark matter spacetimes
Ashok B. Joshi, Divya Tahelyani, Dipanjan Dey +1
Various astrophysical and cosmological observations today serve as an indirect evidence of the existence of dark matter in the universe. In the present work, we propose a class of…
Relativistic orbits of S2 star in the presence of scalar field
Parth Bambhaniya, Ashok B. Joshi, Dipanjan Dey +4
The general theory of relativity predicts the relativistic effect in the orbital motions of S-stars which are orbiting around our Milky-way galactic center. The post-Newtonian or h…
Light trajectory and shadow shape in the rotating naked singularity
Vishva Patel, Divya Tahelyani, Ashok B. Joshi +2
In this paper, we investigate the light trajectories and shadow properties in the rotating version of null naked singularity (NNS) spacetime which is derived using the Newman- Jani…
Comparing thin accretion disk properties of naked singularities and black holes
Divya Tahelyani, Ashok B. Joshi, Dipanjan Dey +1
In the present paper, we study the thermal properties of the geometrically thin accretion disks surrounding the null naked singularity (NNS) and the first type of Joshi-Malafarina-…
Singularity resolution in gravitational collapse
Karim Mosani, Dipanjan Dey, Kaushik Bhattacharya +1
We investigate the unhindered gravitational collapse of a homogeneous scalar field with nonzero potential, a two-dimensional analog of the Mexican hat-shaped Higgs field potential.…
Shadows and precession of orbits in rotating Janis-Newman-Winicour spacetime
Divyesh N. Solanki, Parth Bambhaniya, Dipanjan Dey +2
In this paper, we construct the rotating Janis-Newman-Winicour (JNW) naked singularity spacetime using Newman-Janis Algorithm (NJA). We analyse NJA with and without complexificatio…
Lense-Thirring effect and precession of timelike geodesics in slowly rotating black hole and naked singularity spacetimes
Parth Bambhaniya, Jay S. Verma, Dipanjan Dey +2
In this paper, we investigate the properties of the Lense-Thirring precession frequency and periastron precession of the relativistic bound orbits in slowly rotating naked singular…
Comparing Shadows of Blackhole and Naked Singularity
Kanwar Preet Kaur, Pankaj S. Joshi, Dipanjan Dey +2
It is now theoretically well established that not only a black hole can cast shadow, but other compact objects such as naked singularities, gravastar or boson stars can also cast s…
On the visibility of singularities in general relativity and modified gravity theories
Karim Mosani, Dipanjan Dey, Pankaj S. Joshi +3
We investigate the global causal structure of the end state of a spherically symmetric marginally bound Lemaitre-Tolman-Bondi (LTB) \cite{Lemaitre, Tolman, Bondi} collapsing cloud…
Causal Structure of Singularity in non-spherical Gravitational Collapse
Dipanjan Dey, Pankaj S. Joshi, Karim Mosani +1
We investigate here the final state of gravitational collapse of a non-spherical and non-marginally bound dust cloud as modeled by the Szekeres spacetime. We show that a directiona…
Globally visible singularity in an astrophysical setup
Karim Mosani, Dipanjan Dey, Pankaj S. Joshi
The global visibility of a singularity as an end state of the gravitational collapse of a spherically symmetric pressureless cloud is investigated. We show the existence of a non-z…
Post-Newtonian properties of EMRI with Power Law Potential
Chinmay N. Gandevikar, Divyesh N. Solanki, Dipanjan Dey
There are many astrophysical scenarios where extreme mass ratio inspiral (EMRI) binaries can be surrounded by matter distribution. The distribution of mass can affect the dynamical…
Towards an observational test of black hole versus naked singularity at the galactic center
Dipanjan Dey, Pankaj S. Joshi, Ashok Joshi +1
While the event horizon of a black hole could cast a shadow that was observed recently, a central singularity without horizon could also give rise to such a feature. This leaves us…
Shadows and negative precession in non-Kerr spacetime
Parth Bambhaniya, Dipanjan Dey, Ashok B. Joshi +3
It is now known that the shadow is not only the property of a black hole, it can also be cast by other compact objects like naked singularities. However, there exist some novel fea…
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…
Precession of timelike bound orbits in Kerr spacetime
Parth Bambhaniya, Divyesh N. Solanki, Dipanjan Dey +3
Astrometric observations of S-stars provide a unique opportunity to probe the nature of Sagittarius-A* (Sgr-A*). In view of this, it has become important to understand the nature a…
Shadow of a Naked Singularity without Photon Sphere
Ashok B. Joshi, Dipanjan Dey, Pankaj S. Joshi +1
It is generally believed that the shadows of either a black hole or naked singularity arise due to photon spheres developing in these spacetimes. Here we propose a new spherically…
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…