A huge H I cloud near a galaxy pair
Hoffman, G. Lyle; Salpeter, E. E.; Lamphier, C.; Roos, T.
NGC 4532 and DDO 137 are a pair of Sm galaxies near the edge of the Virgo Cluster. We report Arecibo observations of a nearby H I cloud of enormous extent and unusual velocity structure. The overall diameter of the cloud is almost 30' (approximately 200 kpc). Emission near the two galaxies in both position and velocity accounts for about 80% of the total H I mass of 2.1 x 10(10) M.. The remaining extended emission is mainly at lower velocity (from about the systemic velocity of the two galaxies down to about 200 km s-1 lower); none of the extended emission appears at velocities higher than the systemic velocity of the pair. The kinematics of the extended cloud are too complex for a unique dynamic interpretation of the system; however, the "indicative dynamic mass" is of order M(dyn) approximately 10(12) M..
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