AST/RO Observations of Atomic Carbon near the Galactic Center

Abstract

We present a coarsely-sampled map of the region |l|<=2 degrees, |b|<=0.1 degrees in the 492 GHz 3P1-->3P0 fine structure transition of neutral carbon, observed with the Antarctic Submillimeter Telescope and Remote Observatory (AST/RO). The distribution of C[I] emission is similar on the large scale to that of CO J=1-->0. On average, the ratio of the integrated intensities, I_{C I}/I_{12CO}, is higher in the Galactic disk than in the Galactic Center region. This result is accounted for by the absorption of 12CO within the clouds located in the outer Galactic disk. I_{C I}/I_{12CO} is surprisingly uniform over the variety of environments near the Galactic Center. On average, C[I] is optically thin (or as optically thin as 13CO(J=1-->0)) even in the dense molecular clouds of the Galactic Center region.