5 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…
Detection of optical quasi-periodic oscillation in the blazar 3C 454.3
Karan Dogra, Alok C. Gupta, C. M. Raiteri +83
We analyzed 19 years of -band data of the blazar 3C 454.3 from the Whole Earth Blazar Telescope (WEBT) archive, along with new data from its members and from public archives suc…
Multi-band optical variability of the blazar OP 313 in the outburst state during 2024-2025
P. U. Devanand, Alok C. Gupta, Karan Dogra +2
We present the analysis results of flux and spectral variability of the blazar OP 313 across intra-night to short-term timescales using BVRI photometric data, gathered over 25 nigh…
Optical Photometric Monitoring of the Blazar OT 355 and Local Standard Stars' Calibration
R. Bachev, Tushar Tripathi, Alok C. Gupta +11
OT 355 (4FGL J1734.3 + 3858) is a relatively rarely studied but highly variable, moderate-redshift (z = 0.975) flat-spectrum radio quasar (blazar). With this work, we aim to study…
Optical Continuum Reverberation Mapping of a Candidate IMBH in a Nearby Seyfert 1 Galaxy
Wenwen Zuo, Hengxiao Guo, Jingbo Sun +25
To investigate the short-term variability and determine the size of the optical continuum emitting region of intermediate-mass black holes (IMBHs), we carried out high-cadence, mul…