59 citations · 177 across the 36 of their papers we have counts for
8 papers · 1 filter
Testing Colour-magnitude Pattern as A Method in the Search for Changing-Look AGNs
Li-tao Zhu, Zhongxiang Wang, P. U. Devanand +6
We develop a simple method to search for changing-look (CL) active galactic nucleus (AGN) candidates, and conduct a test run. In this method, optical variations of AGNs are monitor…
Revisiting radio variability of the blazar 3C 454.3
Ashutosh Tripathi, Alok C. Gupta, Krista Lynne Smith +7
We examine lengthy radio light curves of the flat spectrum radio galaxy 3C 454.3 for possible quasi-periodic oscillations (QPOs). The data used in this work were collected at five…
Multiband Optical Variability of the Blazar 3C 454.3 on Diverse Timescales
Karan Dogra, Alok C. Gupta, C. M. Raiteri +79
Due to its peculiar and highly variable nature, the blazar 3C 454.3 has been extensively monitored by the WEBT team. Here, we present for the first time these long-term optical flu…
Spectral Energy Distribution Variability of the Blazar OJ 287 during 2009-2021
Wenwen Zuo, Alok C. Gupta, Minfeng Gu +11
Using nearly simultaneous radio, near-infrared, optical, and ultraviolet data collected since 2009, we constructed 106 spectral energy distributions (SEDs) of the blazar OJ 287. Th…
X-ray Flux and Spectral Variability of the Blazar OJ 287 with Suzaku
Dongtao Zhou, Zhongli Zhang, Alok C. Gupta +4
We present analyses of Suzaku XIS light curves and spectra of the BL Lac object OJ 287 with observations positioned primarily around proposed recurrent optical outbursts. The first…
Evidence of jet activity from the secondary black hole in the OJ287 binary system
Mauri J. Valtonen, Staszek Zola, Alok C. Gupta +29
We report the study of a huge optical intraday flare on November 12, 2021, at 2 am UT, in the blazar OJ287. In the binary black hole model it is associated with an impact of the se…