Hi All,
This also includes a nice image of Sombrero Ultra Compact Dwarf 1 at the bottom edge of the image a little left of centre looking like a very distant yellowish background elliptical galaxy next to a star (at about 10-oclock from the star).
This "little" enigma is comparable to Omega Centauri in physical size (volume)but about 9x brighter and 10x more massive (more like a dwarf eg). Is ancient like a globular cluster (more than 10gyr old), sits in the halo like a globular cluster.
But it contains moderate metallicity stars (like a dwarf) and screams in x-rays (unlike a dwarf) but seems to have no dark matter (unlike most dwarfs). Is it a compact dwarf galaxy? Is it an odd GC?
It doesn't fit well into either category and may be a transitional object or just plain peculiar and in a class of its own. A mystery.
http://arxiv.org/PS_cache/arxiv/pdf/...901.1693v1.pdf
Best,
Les D