Date/Time Date(s) - 10/09/20033:30 pm - 4:30 pm
Title: Extreme Clusters in the Red-Sequence Cluster Survey
Speaker: Dr. Mike Gladders
Institute: The Observatories of the Carnegie Insitution of Washington
Location: ABB 102
Description:
The Red-Sequence Cluster Survey (RCS) is a ~100 square degree imaging survey designed to locate and characterise galaxy clusters to redshifts as high as 1.4. After a brief description of the complete survey and some of the original RCS results, I will focus the rest of this talk on recent results coming primarily from 8m-class telescope followup of the cluster sample. In particular, I will discuss two “extreme” cluster subsamples: clusters with arcs due to strong lensing of background sources, and clusters at very high redshifts. The strong lensing clusters provide an unambiguous detection of evolution in the RCS sample, and demonstrate that a previously unrecognized sample of “super-lenses” must exist. The high-redshift clusters are particularly powerful for studying the formation epoch and formation process of early-type galaxies; like previous smaller studies, the RCS results indicate that the stars in early-type galaxies formed early in the universe, though with a broader spread in star formation histories than previously indicated.