Intermittent Activity of Jets in AGN

TL;DR

This paper investigates the intermittent activity of jets in active galactic nuclei (AGN), proposing radiation pressure instability as a key mechanism and modeling its effects on observed radio structures and source ages.

Contribution

It introduces a model linking radiation pressure instability to jet intermittency and tests its consistency with observed AGN radio source properties.

Findings

Radiation pressure instability can cause short-term jet activity cycles.

Model explains the ages and structures of Compact Symmetric Objects.

Outbursts from instability influence AGN radio morphology.

Abstract

Large scale X-ray jets that extend to >100 kpc distances from the host galaxy indicate the importance of jets interactions with the environment on many different physical scales. Morphology of X-ray clusters indicate that the radio-jet activity of a cD galaxy is intermittent. This intermittency might be a result of a feedback and/or interactions between galaxies within the cluster. Here we consider the radiation pressure instability operating on short timescales (<10^5 years) as the origin of the intermittent behaviour. We test whether this instability can be responsible for short ages (< 10^4 years) of Compact Symmetric Objects measured by hot spots propagation velocities in VLBI observations. We model the accretion disk evolution and constrain model parameters that may explain the observed compact radio structures and over-abundance of GPS sources. We also describe effects of consequent outbursts.