The high velocity dispersion compact cloud CO-0.30-0.07 is a peculiar
molecular clump discovered in the central moleculr zone of the Milky Way, which
is characterized by its extremely broad velocity emissions (βΌ145Β kmsβ1) despite the absence of internal energy sources. We present new
interferometric maps of the cloud in multiple molecular lines in frequency
ranges of 265--269 GHz and 276--280 GHz obtained using the Sumbmillimeter
Array, along with the single-dish images previously obtained with the ASTE 10-m
telescope. The data show that the characteristic broad velocity emissions are
predominantly confined in two parallel ridges running through the cloud center.
The central ridges are tightly anti-correlated with each other in both space
and velocity, thereby sharply dividing the entire cloud into two distinct
velocity components (+15 km sβ1 and +55 km sβ1). This morphology is
consistent with a model in which the two velocity components collide with a
relative velocity of 40 kmsβ1 at the interface defined by the
central ridges, although an alternative explanation with a highly inclined
expanding-ring model is yet to be fully invalidated. We have also unexpectedly
detected several compact clumps (β²0.1Β pc in radius) likely formed by
shock compression. The clumps have several features in common with typical
star-forming clouds: high densities (106.5β7.5Β cmβ3), rich
abundances of hot-core-type molecular species, and relatively narrow velocity
widths apparently decoupled from the furious turbulence dominating the cloud.
The cloud CO-0.30-0.07 is possibly at an early phase of star formation activity
triggered by the shock impact.Comment: 29 pages, 10 figures, accepted for publication in Ap