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Session 106 - Clusters of Galaxies.
Display session, Saturday, January 10
We present deep ultraviolet observations of a field containing the cluster Abell 2246 (z=0.225) which provide far-ultraviolet (FUV) images of some of the faintest galaxies yet observed in that bandpass. Abell 2246 is within the field of view of Ultraviolet Imaging Telescope (UIT) observations of the quasar HS1700+64, which, as a high-priority target for the Hopkins Ultraviolet Telescope, accumulated over 7100 seconds of UIT FUV exposure time during the Astro-2 mission in March 1995. For objects found on both the FUV and ground-based V images, we obtain FUV (\lambda \sim 1520Åphotometry and V-band photometry as well as near-UV (\lambda \sim 2490Åphotometry from UIT Astro-1 observations, and ground-based I-band photometry. We find five objects in the images which are probably at the distance of Abell 2246, with magnitudes (\lambda1520) between 18.6 and 19.6, and V magnitudes between 18.4 and 19.6. Their absolute fluxes and colors are consistent with their being luminous galaxies undergoing star formation. We interpret the colors of these five objects using redshift-corrected stellar population models, and discuss implications for the star formation history of the cluster.
Program listing for Saturday