Poster Title: Star formation history of the late-type spiral galaxy NGC 300
Abstract: People: Butler D., Martinez-Delgado D., Brandner W.,
We present the first WFPC2 V, I photometry for the Sculptor Group galaxy NGC 300 for four fields ranging from the central region to the outer disk/halo. A dearth of bright stars exists in the central region relative to two disk fields that cannot be explained by observational effects. This supports the Davidge (1998) report of suppressed star formation there during the past 10$^9$\,yr. A comparison of the star formation history of these two disk fields indicates that stars were born at similar epochs and formation continued at significantly different mean rates until 100-200\,Myr ago. The main stellar population is predominantly old, consisting of RGB and AGB stars, based on a synthetic colour magnitude diagram (CMD) analysis. We report that a marked burst of star formation occured in both fields lasting up to 80\,Myr and ended 50-60\,Myr ago. The most likely cause is tidal shocking of molecular gas in or between spiral arms. Z is found to have been more metal poor than 0.006 in both disk fields. We compare our findings to those of M31 and consider them in the framework of galaxy formation.
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