Ashutosh Tripathi (中国科学院新疆天文台)
Abstract:
Quasi-periodic Oscillations (QPOs) have been observed in Active Galactic Nuclei (AGN) across the electromagnetic spectrum. The claimed timescales range from a few tens of minutes to days, weeks, and even a decade. Different models have been proposed to explain these QPOs which are primarily based on the timescales of periodicity. In this talk, I will present the QPOs detected in the X-ray, optical, gamma, and radio light curves of blazars, which constitute a special class of AGN, and the models employed to explain them, with the special emphasis on studying AGN with Transient Exoplanet Survey Satellite (TESS). I will discuss the possibility of the correlation between these multi-wavelength emissions that could be related to the shock propagation. I will also discuss the problems encountered while analyzing these light curves and the advanced techniques used to mitigate them.
Dr. Ashutosh Tripathi is currently an Associate Professor at Xinjiang Astronomical Observatory, Chinese Academy of Sciences. He obtained his Ph.D. in 2019 at Fudan University, Shanghai in Theoretical Astrophysics with Prof. Cosimo Bambi on testing general relativity using X-ray observations of AGN. After his first postdoc at Fudan, he moved to Southern Methodist University, Dallas, Texas in 2022 to work on time-domain astronomy with a NASA grant. After a year, in 2023, he moved to Texas A&M University to work as a postdoctoral research associate before joining XAO as a faculty member. His research interests are time-domain multi-messenger astronomy, X-ray reflection spectroscopy, and machine-learning applications with advanced timing analyses in astrophysics.
