A high-velocity molecular cloud near the center of the Galaxy

We report the detection of a peculiar molecular cloud, CO 0.02-0.02, lying about 5' Galactic east from the center of the Galaxy. (12)CO images taken with Nobeyama Radio Observatory (NRO) 45 m telescope showed that it is relatively compact (similar to 3 x 4 pc(2)) as well as having a very large velocity width (Delta V greater than or equal to 100 km s(-1)). The cloud has a virial mass about 1 order of magnitude larger than the LTE mass, 9 x 10(4) M., indicating the cloud is apparently gravitationally unbound. New observations with the James Clerk Maxwell Telescope 15 m and the NRO 45 m telescopes show that CO 0.02-0.02 is very bright in the CO (J = 3-2) and in the HCN and HCO(+) (J = 1-0) lines. It appears that the environment may have an unusually high density and temperature, which may be related to the very broad CO line width. We propose that CO 0.02-0.02 may have been accelerated, heated, and compressed in a series of supernovae shocks that have occurred within the last (3-5) x 10(4) yr.