Abstract: This is the age of multi-wavelenth (MW) time domain astronomy in which the transient astronomical sources are of great interest due to their rapid change in flux, spectrum and polarization. Simultaneous MW observation of a particular transient source over an extended period of time has importance to understand the emission mechanism in different electromagnetic (EM) bands. Blazar is a subclass of active galactic nuclei (AGN), and among one of the most favourite astronomical transient objects, because they emit radiation in the complete EM spectrum, and their flux, spectrum and polarization are highly variable. In the present talk, I will present some of the key results of blazars we have obtained in single EM band, simultaneous MW, and also detected QPOs in the time series data.
Dr. Alok Chandra Gupta obtained his Ph.D. in 1999 from DDU Gorakhpur University, India. He then worked as a postdoctoral and visiting fellow in various institutes in India, including Landessternwarte, Heidelberg, Germany, from July 1999 to April 2006. He also served as a visiting scientist at the Yunnan Astronomical Observatory (YNAO, Kunming) and the Center for Astrophysics at Guangzhou University from May 2006 to December 2007. In January 2008, Dr. Gupta joined as a permanent faculty member, initially as an Assistant Professor, at ARIES, Nainital, India, and he has been working as a Professor since January 2019. Dr. Gupta's primary research interests include: (1) Multi-wavelength flux, spectral, and polarization variability of Blazars. (2) The search for Quasi-Periodic Oscillations (QPOs) in AGNs. He has reviewed more than 100 research papers for leading astronomy journals. Dr. Gupta has published approximately 150 research papers in top-rated astronomy and astrophysics journals, with over 4,700 citations and an H-index of 40.