10 citations · 32 across the 16 of their papers we have counts for
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Transmutation Timescales for Dark Matter Induced Collapse of Compact Stars into Black Holes
H. A. Adarsha, Chandrachur Chakraborty, Sudip Bhattacharyya
Ultra-heavy asymmetric dark matter (DM) particles captured by compact stars can thermalize, self-gravitate, and collapse to form an endoparasitic black hole (EBH), whose subsequent…
Relativistic outflows power a quasi-periodic eruption: constraints on energetics, mass loss, and emission mechanisms
Joheen Chakraborty, Erin Kara, Wenbin Lu +17
Quasi-periodic eruptions (QPEs) are recurring bursts of X-ray radiation originating from supermassive black holes (SMBHs). They are an unprecedented type of structured, high-amplit…
Tilted thin accretion disks in the full Kerr spacetime and their implications
K. S. Sruthy, Chandrachur Chakraborty, Sudip Bhattacharyya
We derive a steady-state warped-disk equation in the full Kerr spacetime to study the tilt dynamics of a thin, viscous accretion disk around a spinning collapsed object. The formul…
A NICER and AstroSat view of the neutron star low-mass X-ray binary 1A 1246-588
Vaidehi Poojyam, Vikas Mistry, Yash Bhargava +2
Neutron star (NS) low-mass X-ray binary (LMXB) systems depict a variety of X-ray spectral and timing features, which can be useful to probe the accretion-ejection mechanism in the…
Degeneracy in Accretion Disk Spectra from Naked Singularities and Kerr Black Holes: Application to the AGN MCG-06-30-15
Vishva Patel, Sayantan Bhattacharya, Sudip Bhattacharyya +1
Theoretical studies suggest that gravitational collapse can form either a black hole or a visible (naked) singularity. Identifying observational signatures that distinguish these t…
Accretion inside astrophysical objects : Effects of rotation and viscosity
H. A. Adarsha, Chandrachur Chakraborty, Sudip Bhattacharyya
Sub-solar mass black holes could show up in gravitational wave observations in future and near-solar mass black holes might have been involved in the events GW190425 and GW190814.…
Magnetically arrested transmutation of a compact star
H. A. Adarsha, Chandrachur Chakraborty, Sudip Bhattacharyya
We introduce a novel mechanism -- Magnetically Arrested Transmutation (MAT) -- which could be a viable model to account for the observed over-representation of magnetic white dwarf…
AstroSat timing and spectral analysis of the accretion-powered millisecond X-ray pulsar IGR J17591--2342
Akshay Singh, Andrea Sanna, Sudip Bhattacharyya +5
IGR J17591--2342, a transient accretion-powered millisecond X-ray pulsar, was discovered during its 2018 outburst. Here, we present a timing and spectral analysis of the source usi…
Probing properties of nearly two-hundred new active galactic nuclei
Samrat Ghosh, Samir Mandal, Sudip Bhattacharyya +1
We present a comprehensive analysis of the X-ray spectral properties of 198 newly identified active galactic nuclei (AGNs), leveraging archival data from the {\it Chandra} X-ray Ob…
Study of a Tilted Thin Accretion Disk around a Kerr-Taub-NUT black hole
Gargi Sen, Chandrachur Chakraborty, Sudip Bhattacharyya +3
The accreting collapsed object GRO J1655-40 could contain the gravitomagnetic monopole (GMM), and it was shown to be better described by the Kerr-Taub-NUT (KTN) spacetime instead o…
Low Mass Naked Singularities from Dark Core Collapse
Chandrachur Chakraborty, Sudip Bhattacharyya, Pankaj S. Joshi
Near-solar mass black holes (BHs) could have been involved in the two recent gravitational wave events, GW190425 and GW190814. Since such a low mass BH cannot be formed via stellar…
Near- and sub-solar-mass naked singularities and black holes from transmutation of white dwarfs
Chandrachur Chakraborty, Sudip Bhattacharyya
Recent gravitational wave events have suggested the existence of near-solar-mass black holes which cannot be formed via stellar evolution. This has opened up a tantalizing possibil…
Revealing Physical Properties of a Tidal Disruption Event: iPTF16fnl
Mageshwaran Tamilan, Gargi Shaw, Sudip Bhattacharyya +1
Tidal disruption event (TDE) iPTF16fnl shows a relatively low optical flare with observationally very weak X-ray emission and the spectroscopic property that the helium emission li…