X-ray variability patterns in blazars

TL;DR: In this paper, the expected variability patterns of blazars within the two-zone acceleration model, putting special emphasis on flare shapes and spectral lags, were studied, and it was shown that the best way to explain blazar flaring behavior is by varying the rate of particles injected in the acceleration zone.

Abstract: Aims. We study the expected variability patterns of blazars within the two-zone acceleration model, putting special emphasis on flare shapes and spectral lags. Methods. We semi-analytically solve the kinetic equations that describe the particle evolution in the acceleration and radiation zone. We then perturb the solutions by introducing Lorentzian variations in its key parameters and examine the flaring behavior of the system. We apply the above to the X-ray observations of blazar 1ES 1218+304, which exhibited a hard lag behavior during a flaring episode and discuss possibilities of producing it within the context of our model. Results. The steady-state radio to X-rays emission of 1ES 1218+304 can be reproduced with parameters that lie well within the ones generally accepted from blazar modeling. Additionally, we find that the best way to explain its flaring behavior is by varying the rate of particles injected in the acceleration zone.