Rapid VHE variability in blazars

TL;DR

This paper reviews recent observations of rapid very high energy (VHE) variability in blazars, especially PKS 2155-304, and discusses a physical model linking accretion disk fluctuations to jet activity.

Contribution

It provides a comprehensive overview of VHE variability in blazars and proposes a physical scenario connecting accretion disk fluctuations with jet variability.

Findings

Evidence for rapid VHE variability in blazars

Indications of a multiplicative process driving variability

Implications for the central engine of AGN

Abstract

Active Galactic Nuclei (AGN) are known to show significant variability over a wide frequency range. We review observational results on the variability characteristics of blazars in the very high energy (VHE) domain, focusing on recent findings of rapid VHE variability and evidence for an underlying multiplicative driving process in PKS 2155-304. We explore a physical scenario where the variability is assumed to arise due to accretion disk fluctuations transmitted to the jet, and discuss its implications for the central powerhouse.