AST/RO Observations of Atomic Carbon near the Galactic Center

Roopesh Ojha, Antony A. Stark, Henry H. Hsieh, Adair P. Lane, Richard A. Chamberlin, Thomas M. Bania, Alberto D. Bolatto, James M. Jackson, and Gregory A. Wright,Vol #548,2001,AST/RO Observations of Atomic Carbon near the Galactic Center,https://iopscience.iop.org/article/10.1086/318693

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Abstract

We present a coarsely sampled map of the region |l| ≤ 2°, |b| ≤ 0°1 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]/I¹²ᴄᴏ, 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. The ratio I[C I]/I¹²ᴄᴏ 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.