Atomic and Molecular Gas in Colliding Galaxy Systems. I. The Data

We present HI and CO(1-0) interferometric observations of 10 comparable-massinteracting systems obtained at the Very Large Array (VLA) and the Owens ValleyRadio Observatory (OVRO) millimeter array. The primary intent of this study isto investigate the response of cold gas during the early stages of collision ofmassive disk galaxies. The sample sources are selected based on theirluminosity (M_B < -19), projected separation (5-40 kpc), and single dishCO(1-0) content (S_{CO} > 20 Jy km/s). These selection criteria result in asample that primarily consists of systems in the early stages of an interactionor a merger. Despite this sample selection, 50% of the systems show long HItidal tails indicative of a tidal disruption in a prograde orbit. In addition,all (4/4) of the infrared luminous pairs (LIRGs) in the sample show long HItails, suggesting that the presence of a long HI tail can be a possiblesignature of enhanced star formation activity in a collision of gas-richgalaxies. More than half of the groups show a displacement of HI peaks from thestellar disks. The CO(1-0) distribution is generally clumpy and widelydistributed, unlike in most IR-selected late stage mergers -- in fact, CO peaksare displaced from the stellar nucleus in 20% (4/18) of the galaxies withrobust CO detection. HI and CO(1-0) Position Velocity Diagrams (PVDs) androtation curves are also presented, and their comparison with the numericalsimulation analyzed in Paper I show evidence for radial inflow and wideoccurrences of nuclear molecular rings. These results are further quantified byexamining physical and structural parameters derived in comparison withisolated systems in the BIMA SONG sample in our forthcoming paper.