ULTRA-COMPACT DWARFS IN THE COMA CLUSTER

Kristin Chiboucas*, R. Brent Tully, R. O. Marzke, S. Phillipps, J. Price, Eric W. Peng, Neil Trentham, David Carter, Derek Hammer

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)

41 Citations (Scopus)

Abstract

We have undertaken a spectroscopic search for ultra-compact dwarf galaxies (UCDs) in the dense core of the dynamically evolved, massive Coma cluster as part of the Hubble Space Telescope/Advanced Camera for Surveys (HST/ACS) Coma Cluster Treasury Survey. UCD candidates were initially chosen based on color, magnitude, degree of resolution within the ACS images, and the known properties of Fornax and Virgo UCDs. Follow-up spectroscopy with Keck/Low-Resolution Imaging Spectrometer confirmed 27 candidates as members of the Coma cluster, a success rate >60% for targeted objects brighter than M-R = -12. Another 14 candidates may also prove to be Coma members, but low signal-to-noise spectra prevent definitive conclusions. An investigation of the properties and distribution of the Coma UCDs finds these objects to be very similar to UCDs discovered in other environments. The Coma UCDs tend to be clustered around giant galaxies in the cluster core and have colors/metallicity that correlate with the host galaxy. With properties and a distribution similar to that of the Coma cluster globular cluster population, we find strong support for a star cluster origin for the majority of the Coma UCDs. However, a few UCDs appear to have stellar population or structural properties which differentiate them from the old star cluster populations found in the Coma cluster, perhaps indicating that UCDs may form through multiple formation channels.

Original languageEnglish
Article number86
Number of pages26
JournalAstrophysical Journal
Volume737
Issue number2
DOIs
Publication statusPublished - 20 Aug 2011

Keywords

  • galaxies: clusters: individual (Coma)
  • galaxies: dwarf
  • galaxies: star clusters: general
  • globular clusters: general
  • EARLY-TYPE GALAXIES
  • MASSIVE STAR-CLUSTERS
  • SURFACE BRIGHTNESS PROFILES
  • TO-LIGHT RATIOS
  • GLOBULAR-CLUSTERS
  • FORNAX CLUSTER
  • VIRGO-CLUSTER
  • ELLIPTIC GALAXIES
  • STELLAR-SYSTEMS
  • STRUCTURAL PARAMETERS

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