High-Density Molecular Gas in the Infrared-bright Galaxy System VV 114

The new high-resolution CO (3-2) interferometric map of the IR-bright interacting galaxy system VV 114 observed with the Submillimeter Array reveals a substantial amount of warm and dense gas in the IR-bright but optically obscured galaxy, VV 114E, and the overlap region connecting the two nuclei. A 1.8×1.4 kpc concentration of CO (3-2) emitting gas with a total mass of 4×10⁹ M_solar coincides with the peaks of near-IR, mid-IR, and radio continuum emission found previously by others, identifying the dense fuel for the active galactic nucleus and/or the starburst activity there. Extensive CO (2-1) emission is also detected, revealing detailed distribution and kinematics that are consistent with the earlier CO (1-0) results. The widely distributed molecular gas traced in CO (2-1) and the distributed discrete peaks of CO (3-2) emission suggest that a spatially extended intense starbursts may contribute significantly to its large IR luminosity. These new observations further support the notion that VV 114 is approaching its final stage of merger, when a violent central inflow of gas triggers intense starburst activity possibly boosting the IR luminosity above the ultraluminous threshold.