CO Observations of the Dwarf Starburst Galaxy NGC 5253 and the $\bf I_{\bf CO}/N_{\bf H_2}$ Ratio
Session 75 -- Interacting Galaxies and Starbursts
Display presentation, Wednesday, 11, 1995, 9:20am - 6:30pm

## [75.15] CO Observations of the Dwarf Starburst Galaxy NGC 5253 and the $\bf I_{\bf CO}/N_{\bf H_2}$ Ratio

J.L.Turner (UCLA), S.C.Beck (Tel Aviv)

We present observations of the 3 mm continuum and CO emission in the dwarf galaxy NGC 5253. NGC 5253 appears to be undergoing a recent burst of star formation which may be tidally induced by its companion, M83. These aperture synthesis maps were made with the Owens Valley Millimeter Array, and have a resolution of 12$^{\prime\prime}$ x 7$^{\prime\prime}$. There is strong thermal continuum emission at 3 mm at the location of the starburst. However the CO emission is extraordinarily weak. This indicates that CO is a poor tracer of the H$_2$ mass in this galaxy, since the high resolution of the maps rules out beam dilution as a cause of the low single dish CO temperatures. We present a value for the conversion factor from CO intensity to H$_2$ column density, $\rm I_{CO}/N_{H_2}$.

This work was supported in part by NSF grant AST90-22996.