Abstract:
Active galactic nuclei (AGNs) are generally characterizedby extremely highluminosities as they are powered by accretion of matter ontoa super massiveblack hole (SMBH) surrounded by an accretion disk (AD). The accretion ofmatter onto SMBHs yields high radiative efficiencies. They also show signifi-cant rapid variability over diverse timescales i.e. from∼100 s to months andyears. Blazars constitute an ambiguous subset of radio-loud Active Galac-tic Nuclei (RLAGNs) consisting both BL Lacertae objects (BLLacs) withlargely featureless optical spectra and flat spectrum radioquasars (FSRQs)which have prominent emission lines. Blazars are characterized with lumi-nous core, rapid variability over entire electro magnetic (EM) spectra, highradio to optical polarization, superluminal motion, non thermal emission anda Doppler boosted relativistic jet pointing≤10◦with the line of sight (LOS).To provide a more detailed understanding of blazar and its environment, wefirst used blazar variability over diverse timescales whichincluded the statis-tical analysis of observational data using three differentstatistics named asC test, F test andχ2test. For this purpose we reported quasi-simultaneousoptical multiband light curves of 4 blazars and studied their rapid variabilitycharacteristics from minutes to yearly timescales which helped us to probethe location and physical processes related to emission processes taking placein the targets.
Description:
The thesis is awarded by Deen Dayal Upadhyay Gorakhpur University, Gorakhpur, under the supervision of Dr. Alok C. Gupta
