Cold and Warm Gas Outflows in Radio AGN

TL;DR

This paper investigates gas outflows in young radio-loud AGN, revealing that they are common and driven by jet-medium interactions, but their energy output may be insufficient for significant galaxy feedback effects.

Contribution

It provides new observational evidence of gas outflows in young radio AGN and compares cold and warm gas outflows, highlighting their potential impact on galaxy evolution.

Findings

Gas outflows are prevalent in young radio AGN.

Cold gas outflows have higher mass rates than ionized gas.

Outflow kinetic power is a small fraction of galaxy luminosity.

Abstract

The study of the conditions and the kinematics of the gas in the central region of AGN provides important information on the relevance of feedback effects connected to the nuclear activity. Quantifying these effects is key for constraining galaxy evolution models. Here we present a short summary of our recent efforts to study the occurrence and the impact of gas outflows in radio-loud AGN that are in their first phase of their evolution. Clear evidence for AGN-induced outflows have been found for the majority of these young radio sources. The outflows are detected both in (warm) ionized as well in (cold) atomic neutral gas and they are likely to be driven (at least in most of the cases) by the interaction between the expanding jet and the medium. The mass outflow rates of the cold gas (HI) appear to be systematically higher than those of the ionized gas. The former reach up to ~50 Msun/yr, and are in the same range as "mild" starburst-driven superwinds in ULIRGs, whilst the latter are currently estimated to be a few solar masses per year. However, the kinetic powers associated with these gaseous outflow are a relatively small fraction (a few x 10^-4) of the Eddington luminosity of the galaxy. Thus, they do not appear to match the requirements of the galaxy evolution feedback models.