Bibcode
Price, J.; Phillipps, S.; Huxor, A.; Trentham, N.; Ferguson, H. C.; Marzke, R. O.; Hornschemeier, A.; Goudfrooij, P.; Hammer, D.; Tully, R. B.; Chiboucas, K.; Smith, R. J.; Carter, D.; Merritt, D.; Balcells, M.; Erwin, P.; Puzia, T. H.
Bibliographical reference
Monthly Notices of the Royal Astronomical Society, Volume 397, Issue 4, pp. 1816-1835.
Advertised on:
8
2009
Citations
70
Refereed citations
62
Description
The Hubble Space Telescope/Advanced Camera for Surveys (HST/ACS) Coma
Cluster Treasury Survey is a deep two-passband imaging survey of the
nearest very rich cluster of galaxies, covering a range of galaxy
density environments. The imaging is complemented by a recent wide field
redshift survey of the cluster conducted with Hectospec on the 6.5-m
Monolithic Mirror Telescope (MMT). Among the many scientific
applications for these data is the search for compact galaxies. In this
paper, we present the discovery of seven compact (but quite luminous)
stellar systems, ranging from M32-like galaxies down to ultra-compact
dwarfs (UCDs)/dwarf to globular transition objects (DGTOs).
We find that all seven compact galaxies require a two-component fit to
their light profile and have measured velocity dispersions that exceed
those expected for typical early-type galaxies at their luminosity. From
our structural parameter analysis, we conclude that three of the samples
should be classified as compact ellipticals or M32-like galaxies, and
the remaining four being less extreme systems. The three compact
ellipticals are all found to have old luminosity weighted ages (>~12
Gyr), intermediate metallicities (-0.6 < [Fe/H] < -0.1) and high
[Mg/Fe] (>~0.25).
Our findings support a tidal stripping scenario as the formation mode of
compact galaxies covering the luminosity range studied here. We
speculate that at least two early-type morphologies may serve as the
progenitor of compact galaxies in clusters.