CO Observations of the Interacting Galaxy Pair NGC 5394/95

BIMA CO 1-0 observations are presented of the spiral galaxies NGC 5394 andNGC 5395 that have undergone a recent, grazing encounter. In NGC 5394, 80% ofthe CO emission detected by BIMA is concentrated in the central 800 pc (FWHM)starburst region.In an encounter simulation that reproduces some of the mainfeatures of this galaxy pair, a considerable amount of gas in NGC 5394 fallsinto the central region early in the collision. The observed total gasdistribution in the disk of NGC 5394 is lopsided, with more HI, CO, and H-alphaemission coming from the western or southwestern side. The innermost westernarm of NGC 5394 is seen in CO and H-alpha emission, but the eastern inner-diskarm, which is very bright in the optical continuum, is not detected in CO orH-alpha emission. From a comparison of the radio continuum, H-alpha, 60 micron,and CO luminosities, we estimate that the average visual extinction of thestarburst is 3 - 4 mag and the conversion factor N(H2)/I(CO) in the starburstis a factor of 3 - 4 below the standard value. Comparison of NGC 5394 with twoother systems previously studied suggests that in prograde grazing encounters acentral starburst may not develop until near the end of the ocular phase. Verylittle of the CO emission from NGC 5395 found in previous single-dishobservations is detected by BIMA.Comment: AAS-Latex, v5.0, 45 pages including embedded .ps figures. AJ, in pres