Interferometer observations of molecular gas in radio galaxies

TL;DR

This study uses high-resolution interferometric observations to analyze the distribution and kinematics of molecular gas in two radio galaxies, revealing massive, rotating molecular disks and complex absorption features that inform models of radio galaxy evolution.

Contribution

First high-resolution interferometric study comparing molecular gas in two different stages of radio galaxy evolution, revealing detailed gas structures and dynamics.

Findings

Detection of a massive, kinematically disturbed molecular disk in 4C31.04.

Identification of a large, regularly rotating molecular disk in 3C293.

Observation of complex molecular absorption systems against the AGN continuum.

Abstract

We present the first results of a high-resolution study of the distribution and kinematics of molecular gas in two nearby radio galaxies, 4C31.04 and 3C293, representative of two different stages of evolution in radio-loud active galactic nuclei (AGN). These observations, conducted with the IRAM Plateau de Bure Interferometer (PdBI), map with unprecedented spatial resolution (0.5"-1") and sensitivity the emission and absorption of key molecular species such as CO, HCN and HCO+. We report on the detection of a kinematically disturbed and massive (Mgas~10^10Msun) molecular/dusty disk of ~1.4kpc-size fueling the central engine of the compact symmetric object (CSO) 4C31.04. We also report on the detection of a massive (Mgas~10^10Msun) regularly rotating ~7kpc-size disk in the FRII radio galaxy 3C293. A complex system of molecular line absorptions is detected against the mm-continuum source of this galaxy (AGN and jet). We compare the properties of the molecular disks in the two sources and discuss them in the light of the different theories describing the evolution of radio galaxies.