Abstract
We have mapped bright CO J = 7 ..-->.. 6 submillimeter line emission in the central; 10 pc of the Galaxy. This is the first detection of the 7 ..-->.. 6 line from the Galactic center, made with a newly constructed submillimeter heterodyne spectrometer. The 372 ..mu..m CO emission comes from a dense, clumpy disk (n/sub H/roughly-equal3 x 10/sup 4/ cm/sup -3/, mass roughly-equal10/sup 4/ M/sub sun/) of temperature approx.300 K. The luminosity of all CO rotational lines emitted from this approx.4' diameter region is about 2 x 10/sup 4/ L/sub sun/. CO line emission is a major contribution to the cooling of the interstellar gas near Sgr A. Mass outflow from the center or cloud-cloud collisions may cause shocks which heat the warm molecular gas. The kinetic energy dissipation rate in shocks necessary is > or =2 x 10/sup 5/ L/sub sun/. This requires a very large mass-loss rate (> or approx. =0.5 M/sub sun/ yr/sup -1/) or efficient regenerationn of cloud-cloud turbulence throughout the region on a very short time scale (< or =5 x 10/sup 3/ yr). Alternatively, UV radiation from the Galactic center could heat the molecular gas if CO self-shielding is effective. The CO abundancemore » must then be approx.10/sup -4/ in the ''photodissociation'' region (A/sub v/< or =5), where most of the UV energy is absorbed.« less
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