Milky Way has newly discovered companions

Two papers in Arxiv highlight new data about dark matter galaxies near the Milky Way. In the first paper, astro-ph/0608528 , the group reports on the Milky Way satellite dwarf spheroidal (dSph) galaxies, which are the smallest dark matter dominated systems in the universe. Dark matter makes up most of the matter in the universe, but are usually only observed indirectly. The paper claims that the density of dSph objects follow a predictive pattern not expected by astronomers. The paper is in press to be published in Nuclear Physics B .Some researchers from that research group have also announced with additional colleagues, the discovery of five new satellites of the Milky Way in paper astro-ph/0608448 . The new objects were found in Sloan Digital Sky Survey (SDSS). They include four probable new dwarf galaxies -- one each in the constellations of Coma Berenices, Canes Venatici, Leo and Hercules -- together with one unusually extended globular cluster, Segue 1. Their location led to the ironic title of their paper “Cats and Dogs, Hair and A Hero: A Quintet of New Milky Way Companions” In the last two years 10 new Milky Way satellites have been discovered in the SDSS which are less luminous, more irregular and appear to be more metal-poor than the previously-known nine Milky Way dwarf spheroidals. This paper has been submitted to the Astrophysical Journal . Related Links Observed Properties of Dark Matter: dynamical studies of dSph galaxies Cats and Dogs, Hair and A Hero: A Quintet of New Milky Way Companions Astrophysical Journal Nuclear Physics B