IAU01620
Presentation type requested: POSTER
STAR FORMATION EFFICIENCY VS ENVIRONMENT
Marianne T Doyle
University of Queensland
Star formation in galaxies is very sensitive to local environment, almost ceasing in regions of high galaxy density. This density-morphology relation has been recognized for decades, but its underlying physical cause is still unclear. The new HI Parkes All-Sky 21cm Survey (HIPASS) allows us to investigate the density-morphology relation effect for the first time with a very large galaxy sample selected purely by neutral hydrogen content. The 5000 HIPASS galaxies span a range in local galaxy density from 0.02 to 1.4 galaxies per cubic Mpc. We estimate star formation rates using optical photometry (SuperCOSMOS) and spectroscopy (6dF) as well as radio continuum measurements (ATCA). We introduce a new parameter, the efficiency of star formation which is the ratio of current star formation to measured HI mass. We present measurements of how this varies with local galaxy density in the HIPASS sample and compare the results to models of the density-morphology relation.
Drinkwater Michael J, Koribalski Baerbell S, The Hipass Team
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