Abstract Details

Name: SUSMITA DAS
Affiliation: PRESIDENCY UNIVERSITY
Conference ID: ASI2021_296
Title : Short-Timescale Variability of the Blazar Mrk 421 from AstroSat and Simultaneous Multi-Wavelength Observations
Authors and Co-Authors : Susmita Das (Presidency University), Ritaban Chatterjee (Presidency University), Archishman Khasnovis (Presidency University), Ritesh Ghosh (Visva-Bharati University).
Abstract Type : Poster
Abstract Category : Extragalactic Astronomy
Abstract : We study the multi-wavelength variability of the blazar Mrk 421 at minutes to days timescales using simultaneous data at gamma-rays from Fermi, 0.7-20 keV energies from AstroSat, and optical and near-infrared (NIR) wavelengths from ground-based observatories. We compute the shortest variability timescales to be approximately 1.1 ks at the hard X-ray energies and increasingly longer at soft X-rays, optical and NIR wavelengths as well as at the GeV energies. We estimate the value of the magnetic field to be 1.3 Gauss and the Lorentz factor of the emitting electrons to be approximately 100,000 assuming that synchrotron radiation cooling drives the shortest variability timescale. Blazars vary at a large range of timescales often from minutes to years. These results as obtained here from the very short end of the range of variability timescales of blazars are a confirmation of the leptonic scenario and in particular the synchrotron origin of the X-ray emission from Mrk 421. This particular mode of confirmation has been possible using minutes to days timescale variability data obtained from AstroSat and simultaneous multi-wavelength observations.