373 research outputs found
Spectroscopy of a Globular Cluster in the Local Group dIrr NGC 6822
We present low-resolution Keck spectroscopy for the globular cluster H VIII
in the Local Group dIrr galaxy NGC 6822. We find the metallicity of the cluster
to be [Fe/H]= -1.58 +/- 0.28 and the age of the cluster to be 3-4 Gyr, slightly
older than but consistent with previous age estimates. H VIII seems to be more
metal-poor than most intermediate-age globular clusters in the Local Group, and
appears most similar to the anomalous Small Magellanic Cloud clusters Lindsay
113 and NGC 339.Comment: 5 pages, including 3 figures. Accepted by MNRAS, uses mn2e.cl
Galaxy Disruption in a Halo of Dark Matter
The relics of disrupted satellite galaxies around the Milky Way and Andromeda
have been found, but direct evidence of a satellite galaxy in the early stages
of being disrupted has remained elusive. We have discovered a dwarf satellite
galaxy in the process of being torn apart by gravitational tidal forces as it
merges with a larger galaxy's dark matter halo. Our results illustrate the
morphological transformation of dwarf galaxies by tidal interaction and the
continued build-up of galaxy halos.Comment: 7 pages, Latex, 4 figures, to appear in Science v301 p563
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