AAS Meeting #193 - Austin, Texas, January 1999
Session 70. Star Formation and the ISM in Galaxies
Display, Friday, January 8, 1999, 9:20am-6:30pm, Exhibit Hall 1

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[70.12] The BIMA CO Survey Of Nearby Spiral Galaxies (BIMA SONG): A Comparison of CO Emission and Dust

K. Sheth (UMD), M. W. Regan (DTM-CIW), M. D. Thornley (NRAO), L. Blitz, D. C.-J. Bock (UCB), A. Harris (UMD), T. T. Helfer (NRAO), S. N. Vogel (UMD), T. Wong (UCB)

We present new results from the ongoing BIMA CO (J=1-0) Survey of Nearby Galaxies (SONG). The BIMA SONG includes 44 spiral (Sa-Sd) galaxies with MB < 11, VHEL < 2000 km s-1, inclination < 70o and declination > -20o, of which more than half have already been observed with the BIMA mm-array. Galaxies for which CO emission is known to be extended are observed with a 7-field mosaic with a 3-4' FOV at 7'' angular resolution and 5 km/s spectral resolution; the remainder are a small minority and these are observed with a single central pointing (FOV~2').

In this poster, we discuss the large variations in CO morphology revealed by SONG, and compare the CO maps with optical and near-IR images. Though CO is the most widely used tracer of molecular gas, the exact value for the ratio of CO luminosity to H2 mass is controversial; another tracer of the molecular gas which can be used for comparison is dust. We derive dust extinction maps from optical-infrared color maps using a multiple-scattering radiative transfer model. In most galaxies, we find qualitative agreement between the CO emission and dust extinction distributions, indicating that CO is a reliable tracer of the dense gas distribution. Using H2 column densities inferred from the dust extinction maps, we study variations in the CO-to-H2 conversion factor within individual galaxies and between galaxies.

If you would like more information about this abstract, please follow the link to http://www.astro.umd.edu/~kartik/survey.html. This link was provided by the author. When you follow it, you will leave the Web site for this meeting; to return, you should use the Back comand on your browser.

The author(s) of this abstract have provided an email address for comments about the abstract: kartik@astro.umd.edu

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