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Session 82 - Spirals & Irregulars.
Display session, Friday, January 09
Exhibit Hall,

[82.15] The Relation between Gas Density and Star Formation in S0 Galaxies

A. Birmingham (Amherst College), J. Eder, C. Salter (NAIC)

As a morphological class, S0 galaxies are considered to have featureless disks devoid of prominent indicators of ongoing star formation. We have been studying a group of galaxies, classified as S0, which have neutral hydrogen contents (H I) comparable to those of star-forming spiral galaxies, and which show evidence of low levels of recent star formation on blue and H-alpha CCD images. In order to study the relation of the global gas content and the gas surface density to star formation at the lower extremes, we have observed and detected three of these gas-rich S0 galaxies in the CO(J=1-0) line at 115 GHz with the NRAO 12-meter telescope.

When the molecular gas content was estimated from the CO spectra, we found that the ratio of molecular to neutral gas mass for each galaxy was within the range of values reported for spiral galaxies. Using our VLA (C-array) H I maps of these galaxies, we were able to compare the radial distributions of the total gas surface density and the H-alpha emission.

Program listing for Friday