activity
20092026
most citedA ~4.6 h quasi-periodic oscillation in the BL Lacertae PKS 2155-304?

88 citations · 1.2k across the 44 of their papers we have counts for

collaborators

45 papers

astro-ph.HE2026

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…

astro-ph.HE2026

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…

astro-ph.HE2025

Signature of Seyfert-like component in a blazar 3C 273 and its reflection-based explanation

Haritma Gaur, Main Pal, Muhammad S. Anjum +4

We present the results of blazar 3C 273 obtained from simultaneous observations obtained using XMM-Newton and NuSTAR satellites during the period 2015-2019 in five epochs. When the…

astro-ph.HE2023

Optical intra-day variability of the blazar S5 0716+714

Tushar Tripathi, Alok C. Gupta, Ali Takey +18

We present an extensive recent multi-band optical photometric observations of the blazar S5 0716+714 carried out over 53 nights with two telescopes in India, two in Bulgaria, one i…

astro-ph.HE2023★ 15 cited

Quasi-simultaneous Optical Flux and Polarization Variability of the Binary Super Massive Black Hole Blazar OJ 287 from 2015 to 2023: Detection of an Anticorrelation in Flux and Polarization Variability

Alok C. Gupta, Pankaj Kushwaha, Mauri J. Valtonen +25

We study the optical flux and polarization variability of the binary black hole blazar OJ 287 using quasi-simultaneous observations from 2015 to 2023 carried out using telescopes i…

astro-ph.HE2023

Multi-band optical variability on diverse timescales of the TeV blazar TXS 0506+56, the first cosmic neutrino source

Vinit Dhiman, Alok C. Gupta, Rumen Bachev +9

We report the first extensive optical flux and spectral variability study of the TeV blazar TXS 0506+056 on intra-night to long-term timescales using BVRI data collected over 220 n…