Multi-Wavelength study of blazar flares

Abstract

Blazars are the most powerful Active Galactic Nuclei (AGNs) with relativistic jets oriented close to the observer’s line of sight. Their total spectral energy distributions (SEDs) show two hump like structures. One peaking in low energy band (IR - X-ray) and another in high energy band (X-ray – gamma-ray). Low energy peak is well described by synchrotron emission. The origin of high energy peak is still under debate. However, we have two different models (leptonic and hadronic) that can explain the high energy peak. A sequence of blazar sub-classes, from FSRQ to low frequency peaked BL LAC objects (LBLs) to high frequency peaked BL LACs (HBLs), can be defined through the presence or absence of emission lines in their optical spectra and the peak frequencies of the synchrotron emission. This thesis aims to understand the multi-wavelength properties of FSRQ type blazars. Temporal and spectral studies are done for two FSRQs in the multi-wavelength regime, from gamma-ray to optical and radio waveband.