A New Milky Way Dwarf Satellite in Canes Venatici
/ Authors
D. Zucker, V. Belokurov, N. Evans, M. Wilkinson, M. Irwin, T. Sivarani, S. Hodgkin, D. Bramich, J. Irwin, G. Gilmore
and 37 more authors
B. Willman, S. Vidrih, M. Fellhauer, P. Hewett, T. Beers, E. F. Bell, E. Grebel, D. P. Schneider, H. Newberg, R. Wyse, C. Rockosi, B. Yanny, R. Lupton, J. A. Smith, J. Barentine, H. Brewington, J. Brinkmann, M. Harvanek, S. J.Kleinman, J. Krzesinski, D. Long, A. Nitta, S. University, M. University, N. University, Mpia, Heidelberg, U. Basel, P. S. University, Rensselaer Polytechnic Institute, Jhu, Lick ObservatoryUCSC, Fnal, P. University., Lanl, A. P. Observatory, Cracow Pedagogical University
/ Abstract
In this Letter, we announce the discovery of a new dwarf satellite of the Milky Way, located in the constellation Canes Venatici. It was found as a stellar overdensity in the north Galactic cap using Sloan Digital Sky Survey Data Release 5 (SDSS DR5). The satellite's color-magnitude diagram shows a well-defined red giant branch as well as a horizontal branch. As judged from the tip of the red giant branch, it lies at a distance of ~220 kpc. Based on the SDSS data, we estimate an absolute magnitude of MV ~ -7.9, a central surface brightness of μ0, V ~ 28 mag arcsec-2, and a half-light radius of ~8.′5 (~550 pc at the measured distance). The outer regions of Canes Venatici appear extended and distorted. The discovery of such a faint galaxy in proximity to the Milky Way strongly suggests that more such objects remain to be found.
Journal: The Astrophysical Journal Letters
DOI: 10.1086/505216