AST/RO Observations of Atomic Carbon near the Galactic Center
  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. 
Roopesh Ojha, Antony A. Stark, Henry H. Hsieh, Adair P. Lane, Richard   A. Chamberlin, Thomas M. Bania, Alberto D. Bolatto, ...