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Wide field camera observations of Baade's WindowWe have observed a field in Baade's Window using the Wide Field Camera (WFC) of the Hubble Space Telescope (HST) and obtain V- and I-band photometry down to V approximately 22.5. These data go several magnitudes fainter than previously obtained from the ground. The location of the break in the luminosity function suggests that there are a significant number of intermediate age (less than 10 Gyr) stars in the Galactic bulge. This conclusion rests on the assumptions that the extinction towards our field is similar to that seen in other parts of Baade's Window, that the distance to the bulge is approximately 8 kpc, and that we can determine fairly accurate zero points for the HST photometry. Changes in any one of these assumptions could increase the inferred age, but a conspiracy of lower reddening, a shorter distance to the bulge, and/or photometric zero-point errors would be needed to imply a population entirely older than 10 Gyr. We infer an initial mass function slope for the main-sequence stars, and find that it is consistent with that measured in the solar neighborhood; unfortunately, the slope is poorly constrained because we sample only a narrow range of stellar mass and because of uncertainties in the observed luminosity function at the faint end.
Document ID
19950044751
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Holtzman, Jon A.
(Lowell Observatory, Flagstaff, AZ United States)
Light, R. M.
(California Institute of Technology, Pasadena, CA United States)
Baum, William A.
(University of Washington, Seattle, WA United States)
Worthey, Guy
(University of Michigan, Ann Arbor, MI United States)
Faber, S. M.
(University of California, Santa Cruz, Santa Cruz, CA United States)
Hunter, Deidre A.
(Lowell Observatory, Flagstaff, AZ United States)
O'Neil, Earl J., Jr.
(National Optical Astronomy Observatories, Tucson, AZ United States)
Kreidl, Tobias J.
(Lowell Observatory, Flagstaff, AZ United States)
Groth, E. J.
(Princeton University Princeton, NJ, United States)
Westphal, James A.
(California Institute of Technology, Pasadena, CA United States)
Date Acquired
August 16, 2013
Publication Date
November 1, 1993
Publication Information
Publication: Astronomical Journal
Volume: 106
Issue: 5
ISSN: 0004-6256
Subject Category
Astronomy
Accession Number
95A76350
Funding Number(s)
CONTRACT_GRANT: NAS5-1661
Distribution Limits
Public
Copyright
Other

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