A PHOTOMETRIC METALLICITY ESTIMATE OF THE VIRGO STELLAR OVERDENSITY
- Infrared Processing and Analysis Center, California Institute of Technology, Mail Stop 100-22, Pasadena, CA 91125 (United States)
- Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States)
- Department of Physics and Astronomy and JINA (Joint Institute for Nuclear Astrophysics), Michigan State University, E. Lansing, MI 48824 (United States)
- Service d'Astrophysique, CEA/DSM/IRFU/SAp, CEA Saclay, 91191 Gif-sur-Yvette Cedex (France)
- Fermi National Accelerator Laboratory, P.O. Box 500, Batavia, IL 60510 (United States)
We determine photometric metal abundance estimates for individual main-sequence stars in the Virgo Overdensity (VOD), which covers almost 1000 deg{sup 2} on the sky, based on a calibration of the metallicity sensitivity of stellar isochrones in the gri filter passbands using field stars with well-determined spectroscopic metal abundances. Despite the low precision of the method for individual stars, we derive [Fe/H] = -2.0 +- 0.1(internal) +- 0.5(systematic) for the metal abundance of the VOD from photometric measurements of 0.7 million stars in the northern Galactic hemisphere with heliocentric distances from approx10 kpc to approx20 kpc. The metallicity of the VOD is indistinguishable, within DELTA[Fe/H] <= 0.2, from that of field halo stars covering the same distance range. This initial application suggests that the Sloan Digital Sky Survey gri passbands can be used to probe the properties of main-sequence stars beyond approx10 kpc, complementing studies of nearby stars from more metallicity-sensitive color indices that involve the u passband.
- OSTI ID:
- 21389291
- Journal Information:
- Astrophysical Journal (Online), Journal Name: Astrophysical Journal (Online) Journal Issue: 1 Vol. 707; ISSN 1538-4357
- Country of Publication:
- United States
- Language:
- English
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