9959(  1) - 04/04/03 10:40  - [  1]

    PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS   ST ScI Use Only
                                                       ID:      9959
                                                       Version: 1
                                                       Check-in Date: 04-Apr-2003
                                                                      10:40:18

1.Proposal Title:
Archival HST Studies of Six Globular Clusters
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2. Proposal For  3. Cycle
AR               11
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4. Investigators
                                                                                     Contact?
    PI: Walter Lewin                      Massachusetts Institute of Technology
   CoI: Prof. Scott Anderson              University of Washington                      N
   CoI: Dr. Lee Homer                     University of Washington                      N
   CoI: Dr. Bruce Margon                  Space Telescope Science Institute             N
   CoI: Dr. David Pooley                  Massachusetts Institute of Technology         N
   CoI: Prof. Frank Verbunt               Universiteit Utrecht, Sterrekundig            N
                                          Instituut

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5. Abstract

We propose to examine the archival HST data on six globular clusters to identify the
natures of the close binaries observed in these clusters with Chandra. Our ultimate
goal is to study the dynamical evolution of globular clusters by observing their
populations of close binaries, which are fundamental to the evolution and dynamical
stability of a cluster. We have an ongoing Chandra program to observe globular
clusters which span a range of physical parameters (such as central concentration,
size, and mass) and have so far been awarded deep observations of nine globular
clusters. The Chandra observations are the most effective means of finding certain
populations of close binaries (such as low- mass X-ray binaries, cataclysmic
variables, millisecond pulsars, and active main-sequence binaries). The HST data are
absolutely necessary to find the counterparts of the observed X-ray sources, which
is a key step in determining their nature. Using archival HST data, we have
successfully applied this approach in our analysis of NGC 6752, in which we found
counterparts for 12 of the 19 X-ray sources. We propose to continue this work for
five more of our clusters for which good HST data exist in the archive, as well as
undertake a variability study of the HST sources in NGC 6752.
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                                                9959(  1) - 04/04/03 10:40  - [  2]

            Summary Form for Proposal  9959

  Item                         Used in this proposal
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  Proposal Category            AR
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