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15-Year X-ray Study Links Variable Mass Accretion to Changing Look Behavior in AGN NGC 7582
Santanu Mondal, V. Jithesh, Neeraj Kumari +1
Changing Look Active Galactic Nuclei (CLAGN) are a subclass of AGN that exhibit spectral state transitions in both optical/UV and X-ray bands on timescales of days to years. In thi…
Temporal Variation of the Coronal Radius Parameter in a Jetted Tidal Disruption Event: Swift J1644+57
Arka Chatterjee, Kimitake Hayasaki, Prantik Nandi +5
Tidal Disruption Events are exotic astrophysical phenomena where matter from a star or the interstellar medium is captured by a supermassive black hole. The process liberates enorm…
Discovery of Changing-Look behavior in AGN NGC 3822: A long-term multiwavelength study
Narendranath Layek, Prantik Nandi, Sachindra Naik +7
We present a comprehensive long-term multi-wavelength study of the active galactic nucleus (AGN) NGC 3822, based on 17 years (2008 to 2025) of X-ray, ultraviolet (UV), and optical…
Optical spectroscopy of 1A 0535+262 before, during, and after the 2020 giant X-ray outburst
Sachindra Naik, Birendra Chhotaray, Neeraj Kumari
We present the findings from our study of the Be/X-ray binary 1A 0535+262/HD 245770 during the giant X-ray outburst in October 2020. We utilized the 1.2-m telescope at Mount Abu In…
Long-term X-ray temporal and spectral study of a Seyfert galaxy Mrk 6
Narendranath Layek, Prantik Nandi, Sachindra Naik +3
We present a long-term X-ray study of a nearby Active Galactic Nucleus Mrk 6, utilizing observations from XMM-Newton, Suzaku, Swift and NuSTAR observatories, spanning 22 years from…
Long-term study of the first Galactic ultraluminous X-ray source Swift J0243.6+6124 using NICER
Birendra Chhotaray, Gaurava K. Jaisawal, Prantik Nandi +4
We present the results obtained from detailed X-ray timing and spectral studies of X-ray pulsar Swift J0243.6+6124 during its giant and normal X-ray outbursts between 2017 and 2023…
The accretion properties of a low-mass Active Galactic Nucleus: UGC 6728
Prantik Nandi, Sachindra Naik, Arka Chatterjee +3
We present a comprehensive analysis of approximately years () of X-ray observations of UGC~6728, a low-mass bare AGN, for the first time. Our study encompasses both…
Coronal Properties of Low-Accreting AGNs using Swift, XMM-Newton and NuSTAR Observations
Arghajit Jana, Arka Chatterjee, Hsiang-Kuang Chang +6
We studied the broadband X-ray spectra of {\it Swift}/BAT selected low-accreting AGNs using the observations from {\it XMM-Newton}, {\it Swift}, and {\it NuSTAR} in the energy rang…
Investigation of a small X-ray flaring event in NLS1 galaxy NGC 4051
Neeraj Kumari, Arghajit Jana, Sachindra Naik +1
We performed a detailed broadband spectral and timing analysis of a small flaring event of ~120 ks in a narrow-line Seyfert 1 galaxy NGC 4051 using simultaneous XMM-Newton and NuST…
Optical and X-ray studies of Be/X-ray binary 1A 0535+262 during its 2020 giant outburst
Birendra Chhotaray, Gaurava K. Jaisawal, Neeraj Kumari +3
We report results obtained from the optical and X-ray studies of the Be/X-ray binary 1A 0535+262/HD 245770 during the 2020 October giant X-ray outburst, using the 1.2 m telescope a…
Absorption Variability of the Highly Obscured Active Galactic Nucleus NGC 4507
Arghajit Jana, Claudio Ricci, Sachindra Naik +6
We present a detailed study of the highly obscured active galaxy NGC 4507, performed using four Nuclear Spectroscopic Telescope Array (NuSTAR) observations carried out between May…
AstroSat Observation of X-ray Dips and State Transition in the Black Hole Candidate MAXI J1803-298
Arghajit Jana, Sachindra Naik, Gaurava K. Jaisawal +3
We present the results obtained from broadband X-ray timing and spectral analysis of black hole candidate MAXI J1803-298 using an AstroSat observation on May 11-12, 2021. Four peri…
Evidence of Heavy Obscuration in the Low-Luminosity AGN NGC 4941
Arghajit Jana, Sachindra Naik, Neeraj Kumari
We present the results obtained from timing and spectral studies of the highly obscured low luminosity active galactic nucleus NGC~4941 using data obtained from the {\it Nuclear Sp…
Broadband X-Ray Observations of the 2018 Outburst of the Changing-Look Active Galactic Nucleus NGC 1566
Arghajit Jana, Neeraj Kumari, Prantik Nandi +5
We study the nature of the changing-look Active Galactic Nucleus NGC 1566 during its June 2018 outburst. During the outburst, the X-ray intensity of the source rises up to ~25-30 t…
Complex optical/UV and X-ray variability in Seyfert 1 galaxy Mrk 509
Neeraj Kumari, Main Pal, Sachindra Naik +3
We performed a detailed spectral and timing analysis of a Seyfert 1 galaxy Mrk 509 using data from the Neil Gehrels Swift observatory that spanned over ~13 years between 2006 and 2…
NICER observations of the black hole candidate MAXI J0637430 during the 2019-2020 Outburst
Arghajit Jana, Gaurava K. Jaisawal, Sachindra Naik +5
We present detailed timing and spectral studies of the black hole candidate MAXI J0637430 during its 2019-2020 outburst using observations with the {\em Neutron Star Interior Co…
Accretion Properties of MAXI J1813-095 during its Failed Outburst in 2018
Arghajit Jana, Gaurava K. Jaisawal, Sachindra Naik +7
We present the results obtained from detailed timing and spectral studies of a black hole candidate MAXI~J1813-095 using {\it Swift}, {\it NICER}, and {\it NuSTAR} observations dur…
Short-Timescale Variability of the Blazar Mrk 421 from AstroSat and Simultaneous Multi-Wavelength Observations
Ritaban Chatterjee, Susmita Das, Archishman Khasnovis +13
We study the multi-wavelength variability of the blazar Mrk 421 at minutes to days timescales using simultaneous data at -rays from Fermi, 0.7-20 keV energies from AstroSat, and…
Spectro-Timing Analysis of a highly variable narrow-line Seyfert 1 galaxy NGC 4748 with AstroSat and XMM-Newton
Main Pal, Neeraj Kumari, Pankaj Kushwaha +8
We present a detailed timing and spectral study of an extremely variable narrow-line Seyfert~1 galaxy NGC 4748 using observations in the year 2017 and 2014 performed with AstroSat…
Blazar OJ 287 After First VHE Activity: Tracking the Re-emergence of the HBL like Component in 2020
Pankaj Kushwaha, Main Pal, Nibedita Kalita +5
We report the re-emergence of a new broadband emission through a detailed and systematic study of the multi-wavelength spectral and temporal behavior of OJ 287 after its first-ever…
Revisiting the spectral and timing properties of 4U 1909+07 with NuSTAR and Astrosat
Gaurava K. Jaisawal, Sachindra Naik, Wynn C. G. Ho +3
We present the results obtained from the analysis of high mass X-ray binary pulsar 4U 1909+07 using NuSTAR and Astrosat observations in 2015 and 2017 July, respectively. X-ray puls…
Probing Nuclear and Circumnuclear Properties of NGC 6300 using X-ray Observations
Arghajit Jana, Arka Chatterjee, Neeraj Kumari +3
We present the results obtained from a detailed X-ray timing and spectral analysis of Seyfert 2 galaxy NGC 6300 by using observations with the {\it Suzaku}, {\it Chandra} and {\it…
Accretion Flow Evolution of a New Black Hole Candidate MAXI J1348-630 During the 2019 Outburst
Arghajit Jana, Dipak Debnath, Debjit Chatterjee +5
Galactic black hole candidate MAXI~J1348-630 was recently discovered by {\it MAXI} and {\it Swift}/BAT satellites during its first outburst in 2019 January which continued for $\si…