Cats and Dogs, Hair and A Hero: A Quintet of New Milky Way Companions

Journal Article · Tue Aug 01 04:00:00 EDT 2006 · Astrophys.J.654:897-906,2007

OSTI ID:897899

Belokurov, V; Zucker, Daniel B; Evans, N W; Kleyna, J T; Koposov, S; Hodgkin, S T; Irwin, M J; Gilmore, G; Wilkinson, M I; Fellhauer, M; Bramich, D M

We present five new satellites of the Milky Way discovered in Sloan Digital Sky Survey (SDSS) imaging data, four of which were followed-up with either the Subaru or the Isaac Newton Telescopes. 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. We provide distances, absolute magnitudes, half-light radii and color-magnitude diagrams for all five satellites. The morphological features of the color-magnitude diagrams are generally well described by the ridge line of the old, metal-poor globular cluster M92. In the last two years, a total of ten new Milky Way satellites with effective surface brightness {mu}{sub v} {approx}> 28 mag arcsec{sup -2} have been discovered in SDSS data. They are less luminous, more irregular and appear to be more metal-poor than the previously-known nine Milky Way dwarf spheroidals. The relationship between these objects and other populations is discussed. We note that there is a paucity of objects with half-light radii between {approx} 40 pc and {approx} 100 pc. We conjecture that this may represent the division between star clusters and dwarf galaxies.

• Research Organization: Fermi National Accelerator Laboratory (FNAL), Batavia, IL
• Sponsoring Organization: USDOE
• DOE Contract Number: AC02-07CH11359
• OSTI ID: 897899
• Report Number(s): FERMILAB-PUB-06-383-CD; arXiv eprint number astro-ph/0608448
• Journal Information: Astrophys.J.654:897-906,2007, Journal Name: Astrophys.J.654:897-906,2007
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
Astrophysics
BRIGHTNESS
GALAXIES
HAIR
MILKY WAY
SATELLITES
SKY
STAR CLUSTERS
TELESCOPES