Effect of turbulence on blazar variability - I: Short time-scale variability within leptonic scenario

Abstract

Blazars are known for showing strong variability over different time-scales in all wavelengths. In this work, we present the study of characterising the short-term variability of blazar in presence of Kraichnan and Kolmogorov types of turbulence within the framework of time-dependent leptonic model. We considered the acceleration of relativistic electrons by both first and second order Fermi processes. The second order Fermi process involves the resonant interaction of the relativistic electrons with magnetohydrodynamics (MHD) turbulence. Along with the acceleration, the relativistic electrons lose energy through synchrotron and synchrotron self-Compton processes. Electrons also escape the acceleration/radiation zone diffusively. A short term variability in photon light curve i.e.'flare' like scenario was generated through an impulsive injection of fresh electrons in the acceleration zone. It is shown that the flare characteristics are different for the two cases of turbulence. We also point out that the evolution of the particle and photon spectra differ for these two turbulence scenarios during flare.