Interferometer observations of molecular gas in radio galaxies

We present the first results of a high-resolution study of the distribution and kinematics of molecular gas in two nearby radio galaxies, 4C 31.04 and 3C 293, 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 10 M⊙) molecular/dusty disk of ∼1.4 kpc-size fueling the central engine of the compact symmetric object (CSO) 4C 31.04. We also report on the detection of a massive (Mgas ∼10 10 M⊙) regularly rotating ∼7 kpc-size disk in the FR II radio galaxy 3C 293. 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.