2007A&A...468L..67G

We present the results of high resolution mapping of the CO(1-0) and CO(2-1) emission of the ultraluminous infrared galaxy (ULIRG) IRAS 10190+1322, with the IRAM interferometer, down to an angular resolution of ∼0.3". This object is composed of two interacting galaxies with a projected nuclear separation of 6kpc, and was selected to analyze the physical and dynamical properties of the molecular gas in each galaxy in order to study the conditions that lead a galaxy pair to become ultraluminous in the infrared. With the exception of Arp 220, the closest ULIRG, this is the first time that the CO emission is morphologically and kinematically resolved in the two interacting galaxies of a ULIRG system. In one of the galaxies the molecular gas is highly concentrated, distributed in a circumnuclear disk of 1.7kpc in size. The molecular gas in the presumably less infrared luminous galaxy is distributed in a more extended disk of 7.4kpc. The molecular gas mass accounts for ∼10% of the dynamical mass in each galaxy. Both objects are rich enough in molecular gas, M_gas∼4x10⁹M_☉, as to experience an infrared ultraluminous phase.