8751(  1) - 12/30/99 13:03  - [  1]

    PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS   ST ScI Use Only
                                                       ID:      8751
                                                       Version: 1
                                                       Check-in Date: 30-Dec-1999
                                                                      12:31:56

1.Proposal Title:
The Age of the Central 100 pc of the Galaxy
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2. Proposal For  3. Cycle
AR               9
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4. Investigators
                                                                                     Contact?
    PI: R. Michael Rich                   University of California at Los Angeles
   CoI: Dr. Mark  Morris                  University of California at Los Angeles       N
   CoI: Dr. Donald Figer                  Space Telescope Science Institute             N

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5. Abstract

We propose to compare the age of the Galactic nucleus population with metal rich
globular clusters that are known to be ~ 12 Gyr old. The Galactic nucleus fields lie
behind 10-30 magnitudes of visual extinction, but are now well imaged to the main
sequence turnoff thanks to NICMOS. Preliminary reductions of fields some 10-20
arcmin from the Galactic Center clearly reveal a red clump population some 3.5 mag
brighter than a clearly detected turnoff. These reductions suggest that the nucleus,
even within 20 pc, is dominated by an old stellar population. We propose to produce
color- magnitude diagrams and luminosity functions for archival NICMOS images of
fields lying 20 arcmin, 1^degrees, 2^degrees, and 3^degrees from the Galactic
Center, and to compare these to the old Galactic globular cluster NGC 6553. The
luminosity functions of the bulge field population and the globular cluster can be
directly compared, independent of distance modulus and reddening, by forcing both to
agree at the maximum of the red clump. This method can give very precise relative
ages of different bulge fields, relative to the oldest stars in the Galactic halo.
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                                                8751(  1) - 12/30/99 13:03  - [  2]

            Summary Form for Proposal  8751

  Item                         Used in this proposal
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  Proposal Category            AR
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