X-ray variability patterns in blazars

TL;DR

This paper models X-ray variability in blazars using a two-zone acceleration framework, analyzing flare shapes and spectral lags, and applies it to observations of blazar 1ES 1218+304 to explain its flaring behavior.

Contribution

It introduces a semi-analytical approach to model blazar variability, emphasizing spectral lags and flare shapes, and demonstrates how particle injection rate variations can explain observed flaring patterns.

Findings

Reproduces steady-state emission with accepted parameters.

Explains hard lag behavior during flares.

Identifies particle injection rate variation as key to flaring behavior.

Abstract

We study the expected variability patterns of blazars within the two-zone acceleration model putting special emphasis on flare shapes and spectral lags. We solve semi-analytically the kinetic equations which 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. The steady-state radio to X-rays emission of 1ES 1218+304 can be reproduced with parameters which 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.