UV-Luminous Globular Clusters in NGC 1399
Abstract
Ultraviolet observations have revealed remarkable diversity among oldstellar populations in globular clusters and E/S0 galaxies. Werecently discovered with HST/STIS that globular clusters in the giantelliptical galaxy M87 have the most heavily populated hot horizontalbranches of any stellar systems yet studied. Their far-UV/opticalcolors are up to 1 mag bluer than any Milky Way globular cluster andapproach the theoretical limits for production of hot-HB stars in oldstellar populations. The differences among the metal-poor clusters areparticularly interesting, because it is thought that these objectsreflect the earliest stages of galaxy formation at high redshifts.Here we propose deep ACS far-UV imaging of a second gE galaxy, NGC1399, with a cluster system that is well-studied at longer wavelengths,to determine whether it shares characteristics with M87. Theseobservations bear on aspects of advanced stellar evolution, on thehistories of globular clusters in different environments, and on theinterpretation of the "ultraviolet upturn'' phenomenon in ellipticalgalaxies and its value as a population probe in distant galaxies.
- Publication:
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HST Proposal
- Pub Date:
- July 2006
- Bibcode:
- 2006hst..prop10901O