Molecular gas in nearby elliptical radio galaxies

TL;DR

This study investigates the molecular gas content, distribution, and kinematics in nearby elliptical radio galaxies, revealing generally low molecular gas masses and the presence of central gas disks, with implications for understanding AGN fueling.

Contribution

It provides the first systematic survey of CO emission in powerful radio galaxies selected by radio flux, highlighting their low molecular gas content and the presence of central gas disks.

Findings

Median molecular gas mass is 4x10^8 Msun.

Some galaxies host central molecular gas disks.

Low molecular gas content compared to Seyfert galaxies.

Abstract

Powerful radio-AGN are hosted by massive elliptical galaxies which are usually very poor in molecular gas. Nevertheless the central Black Hole (BH) needs molecular gas for the nuclear activity. Thus it is important to study the origin, the distribution and the kinematics of the molecular gas in such objects. We have performed at the IRAM-30m telescope a survey of the CO(1-0) and CO(2-1) emission in the most powerful radio galaxies of the Local Universe, selected only on the basis of their radio continuum fluxes. The main result of that survey is the low content in molecular gas of such galaxies compared to Seyfert galaxies. The median value of the molecular gas mass is 4x10^8 Msun. Moreover, the CO spectra indicate the presence of a central molecular gas disk in some of these radio galaxies. We complemented this survey with photometric data of SPITZER and IRAS fluxes with the purpose to study the dust and its relation with the molecular gas and AGN.