KINEMATICS AND METALLICITIES IN THE BOOeTES III STELLAR OVERDENSITY: A DISRUPTED DWARF GALAXY?
- Department of Astronomy, University of Virginia, P.O. Box 400325, Charlottesville, VA 22904-4325 (United States)
- Spitzer Science Center, 1200 East California Boulevard, Pasadena, CA 91125 (United States)
We report the results of a spectroscopic study of the Booetes III (BooIII) stellar overdensity carried out with the Hectospec multifiber spectrograph on the MMT telescope. Radial velocities have been measured for 193 BooIII candidate stars selected to have magnitudes and colors consistent with its upper main sequence and lower red giant branch, as well as a number of horizontal-branch candidates. From 20 identified candidate BooIII members, we measure a systemic velocity of V {sub sun} = 197.5 {+-} 3.8 km s{sup -1} and a velocity dispersion of {sigma}{sub o} = 14.0 {+-} 3.2 km s{sup -1}. We use the somewhat large velocity dispersion and the implied highly radial orbit, along with morphological evidence from Grillmair and stellar abundances, to argue that BooIII is likely the first known object observed in a transitional state between being a bound dwarf galaxy and a completely unbound tidal stream.
- OSTI ID:
- 21333842
- Journal Information:
- Astrophysical Journal (Online), Vol. 702, Issue 1; Other Information: DOI: 10.1088/0004-637X/702/1/L9; Country of input: International Atomic Energy Agency (IAEA); ISSN 1538-4357
- Country of Publication:
- United States
- Language:
- English
Similar Records
WILLMAN 1-A PROBABLE DWARF GALAXY WITH AN IRREGULAR KINEMATIC DISTRIBUTION
A Redshift Survey of the Nearby Galaxy Cluster Abell 2199: Comparison of the Spatial and Kinematic Distributions of Galaxies with the Intracluster Medium