Physical processes powering the broadband emission from relativistic jets and the location of emission region are two important questions in current exploration of jet physics. For the former, studying the statistical characteristics: flux histogram, flux variation with excess variability (rms-flux) and power spectral density (PSD) of the long term gamma-ray emission from AGNs consisting of 3 blazars and a radio-galaxy, we show that blazars’ flux histograms are log-normal while neither Gaussian nor log-normal describes the radio-galaxy. Irrespective of histogram, the excess-variability scales linearly with the flux (rms-flux) while the PSD is consistent with a shot noise process. These properties are similar to the statistical properties of X-ray emission from the solar corona and with the theoretical study of randomly oriented, magnetic reconnection powered minijets-in-a-jet model, thereby favoring magnetic-reconnection as the main driver.

In the second part, studying the temporal evolution of the spectra from the blazar OJ 287, which probably host a binary system of SMBHs, we show that the gamma-ray spectra changes in accordance with the appearance of a strong accretion disk emission and broad line region (BLR). The results imply that most of the jet emission is occurring on sub-parsec scales, thereby suggesting that most of the jet energy is dissipated into particles within sub-parsec scales, if it was magnetically dominated in the beginning.