A Faint New Milky Way Satellite in Bootes
astro-ph
/ Authors
V. Belokurov, D. B. Zucker, N. W. Evans, M. I. Wilkinson, M. J. Irwin, S. Hodgkin, D. M. Bramich, J. M. Irwin, G. Gilmore, B. Willman
and 23 more authors
S. Vidrih, H. J. Newberg, R. F. G. Wyse, M. Fellhauer, P. C. Hewett, N. Cole, E. F. Bell, T. C. Beers, C. M. Rockosi, B. Yanny, E. K. Grebel, D. P. Schneider, R. Lupton, J. C. Barentine, H. Brewington, J. Brinkmann, M. Harvanek, S. J. Kleinman, J. Krzesinski, D. Long, A. Nitta, J. A. Smith, S. A. Snedden
/ Abstract
In this Letter, we announce the discovery of a new satellite of the Milky Way in the constellation of Bootes at a distance of 60 kpc. It was found in a systematic search for stellar overdensities in the North Galactic Cap using Sloan Digital Sky Survey Data Release 5 (SDSS DR5). The color-magnitude diagram shows a well-defined turn-off, red giant branch, and extended horizontal branch. Its absolute magnitude is -5.8, which makes it one of the faintest galaxies known. The half-light radius is 220 pc. The isodensity contours are elongated and have an irregular shape, suggesting that Boo may be a disrupted dwarf spheroidal galaxy.