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Session 116 -- Galactic Center and Diffuse Galactic Emission
Oral presentation, Saturday, January 15, 10:15-11:45, Salon IV Room (Crystal Gateway)

[116.07] HCN~in~the~Central~300~pc~of~the~Galaxy

J. M. Jackson (Boston U.), M. H. Heyer (U Mass/FCRAO), T. A. D. Paglione (Boston U.)

Using the QUARRY array on the FCRAO, we have mapped HCN 1-0 emission from the central 300 pc of the Galaxy. Since HCN has a high dipole moment, it unambiguously traces dense molecular gas. We find that the HCN/CO 1-0 luminosity ratio for the central 300 pc is 0.18, larger than that for M82 (0.07), but smaller than that for NGC 253 (0.23) and NGC 1068 (0.4 - 0.9). The Galactic HCN luminosity, however, is much smaller than that for starburst galaxies, by factors of 2 - 40. These results suggest that the average gas densities are simlarly large in the Galactic Center and in starburst nuclei, but that the amount of dense gas is considerably smaller. Consequently, starburst nuclei most likely result from the accumulation of large amounts of dense molecular gas rather than an enhanced star forming efficiency.

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