4 papers
Multi-band optical photometric variability of the blazar OJ 287 from 2015 to 2025
Alok C. Gupta, Karan Dogra, Mark Kidger +101
We present the most densely sampled multi-band optical photometric observations of the peculiar BL Lacertae object OJ 287 from 2015 to 2025 with a focus on its optical activity on…
A fast X-ray transient with chromatic flares: signatures of violent collisions induced by late-time central engine reactivation
Shao-Yu Fu, Cui-Yuan Dai, Ai-Ling Wang +57
Extragalactic Fast X-ray Transients (EFXTs) represent an emerging class of high-energy phenomena characterized by X-ray outbursts lasting from tens to hundreds of seconds. However,…
Detection of quasi-periodic oscillations in the 37 GHz radio light curve of the blazar Ton 599 during 1990-2020
Alok C. Gupta, Alexandr E. Volvach, Shubham Kishore +6
Blazars are a subclass of radio-loud active galactic nuclei (AGNs) that display strong multi-wavelength variability on diverse timescales ranging from years down to minutes. In the…
Deciphering the Physical Origin of GRB 240825A: A Long GRB Lacking a Bright Supernova
Rahul Gupta, Judith L. Racusin, R. Sanchez-Ramirez +52
We present a comprehensive multiwavelength analysis of GRB 240825A, a bright gamma-ray burst (GRB) detected by Fermi and Swift, with a prompt duration ( ~ 4 sec in 50-3…