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M. Hasegan (Rutgers Univ.), A. Jordan (ESO), P. Cote (HIA), S.G. Djorgovski (Caltech), J.P. Blakeslee, S. Mei (Johns Hopkins Univ.), M.J. West (Univ. of Hawaii), E.W. Peng (HIA), D.E. McLaughlin (STScI), L. Ferrarese (HIA), D. Merritt (Rochester Inst. of Tech.), M. Milosavljevic (Caltech), J.L. Tonry (Univ. of Hawaii)
A potentially new type of faint (absolute blue magnitudes between -13 and -11) and compact (effective radii between 10 and 30 pc) stellar system --- ultra-compact dwarf (UCD) galaxies --- has recently been discovered in the Fornax Cluster. This discovery raises questions about the origin and evolution of these objects, their relation to globular clusters (GCs) and normal dwarf galaxies, and their role in hierarchical formation scenarios.
To investigate the characteristics of these objects and their homogeneity as a class, we have obtained information on the structural, kinematic and photometric properties of an expanded sample of UCD candidates in a new and different environment: the Virgo Cluster. We use HST/ACS F475W and F850LP imaging for 100 early-type galaxies from ACS Virgo Cluster Survey, archival F606W WFPC2 imaging for a small sample of ultra-luminous GCs near M87, and Keck/ESI spectroscopy for 10 objects identified as possible UCD candidates. Using this data, we critically examine formation scenarios for UCDs and examine the uniqueness of UCDs as a class.
Support for this program was provided mainly by Space Telescope Science Institute, Association of Universities for Research in Astronomy, Inc., National Aeronautics and Space Administration and National Science Foundation.
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Bulletin of the American Astronomical Society, 36 5
© 2004. The American Astronomical Society.