Accretion Disk Model of Short-Timescale Intermittent Activity in Young Radio Sources

TL;DR

This paper proposes that short-lived, compact radio sources are caused by intermittent activity in the accretion disk of young radio galaxies, driven by radiation pressure instability, explaining their observed properties and limited evolution.

Contribution

It introduces a model linking accretion disk instabilities to short-timescale activity in young radio sources, aligning theoretical timescales with observations.

Findings

Active phases last less than 10^3-10^4 years.

Sources are confined within host galaxies and do not evolve into large radio galaxies.

Model timescales match observed source ages.

Abstract

We associate the existence of short-lived compact radio sources with the intermittent activity of the central engine caused by a radiation pressure instability within an accretion disk. Such objects may constitute a numerous sub-class of Giga-Hertz Peaked Spectrum sources, in accordance with the population studies of radio-loud active galaxies, as well as detailed investigations of their radio morphologies. We perform the model computations assuming the viscosity parametrization as proportional to a geometrical mean of the total and gas pressure. The implied timescales are consistent with the observed ages of the sources. The duration of an active phase for a moderate accretion rate is short enough (< 10^3-10^4 years) that the ejecta are confined within the host galaxy and thus these sources cannot evolve into large size radio galaxies unless they are close to the Eddington limit.