Abstract:
Blazars are sub-class of the radio-loud Active Galactic Nuclei (AGN), which
emit extremely luminous, polarized and non-thermal radiation covering the entire
electromagnetic spectrum from a highly compact center (i.e., SMBH). The blazars
with higher luminosity and jet angle are known as FSRQs (Flat spectrum radio
quasars), while the BL Lac objects show comparatively low luminosity and smaller
jet angle (in both cases the jet angle is ≤ 10°). Moreover, the SED synchrotron
peak of FSRQs lies in the radio to optical range but for BL Lacs the synchrotron
hump peaks in optical to X-ray range. One of the most interesting phenomenon
that blazars show is the multi-frequency flux variation on diverse timescales. In the
X-ray domain almost all blazars are strong emitters and it is found from studying
emission line properties in X-ray spectra, that the X-ray emissions are coming from
regions nearer to the SMBH. So, X-ray study of blazars can give deeper insight of
the central engine improving our understanding of the source. In this thesis our aim
is to understand different physical mechanisms involved with X-ray emission and
to get better understanding of different variability properties observed in blazars. In
order to investigate this we have undertaken two different approaches : (1) temporal
study in multi-frequency domain and (2) X-ray spectral study. The whole work
presented in this thesis is based on the blazar observations made by XMM-Newton
observatory since its launch.
