Assigned ID: 404 ----- Attempting Submission 1 (Fri Feb 26 16:50:22 GMT 2010) ----- HST Phase I Proposal 404 (rudnick.apt) successfully submitted. ----- Attempting Submission 2 (Fri Feb 26 23:54:41 GMT 2010) ----- Dense regions of the universe, such as groups and clusters, have a significantly higher fraction of red and dead early-type galaxies than the field. Despite much work on the subject, it is nonetheless unclear if this difference actually results from a transformation of galaxies as they enter dense environments. We will address this in a new way by measuring the current star formation rate (SFR), recent star formation history (SFH), and evidence for ongoing morphological transformation in a set of very well studied cluster, group, and field galaxies, all at an epoch where the galaxy population was rapidly evolving. With this analysis we will determine the relative sequencing of star formation suppression and morphological transformation in a range of environments and as a function of galaxy mass. We have all the elements in place to carry out this program and ask in this proposal for funds to: 1) analyze HST/ACS data for a set of z~0.7 galaxies in 12 clusters, 7 groups, and the field to measure weak morphological distortions of the sort likely to produce early type galaxies from spirals; 2) use the detailed output of state-of-the-art minor merger simulations to determine the timescales over which the distortions are observable; 3) link the evidence of morphological transformation to the recent SFH and current SFR using our extensive 8-meter spectroscopy and multi-wavelength data for our target galaxies.

COSMOLOGY 12 75869 false 0.0 0.0 false false false false false false SUPPORTED