9555(  1) - 12/06/01 12:57  - [  1]

    PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS   ST ScI Use Only
                                                       ID:      9555
                                                       Version: 1
                                                       Check-in Date: 06-Dec-2001
                                                                      11:52:20

1.Proposal Title:
A Kinematic Study of Disk Systems in Galaxy Cluster Cl0024+16 at z=0.39
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2. Proposal For  3. Cycle
AR               11
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4. Investigators
                                                                                     Contact?
    PI: David Koo                         University of California
                                          Observatories/Lick Observatory
   CoI: Ms. Anne Metevier                 University of California, Santa Cruz          N

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5. Abstract

For over twenty years, distant galaxy clusters have been a key arena for galaxy
evolution studies. Despite many major discoveries, the physical mechanisms that
drive cluster galaxy evolution remain a mystery and largely untested. Viable
proposed processes include merging, ``harassment'', starbursts, ram-pressure
stripping, and infall of groups, all of which involve disks and gas, and are
expected to change the mass-to-light ratios of cluster galaxies. While recent
studies have concentrated on bulge-dominated galaxies, we will instead focus on the
evolution of disks in distant clusters. As an initial foray into this new area, we
propose an intensive study of distant disks combining archival WFPC2 data of cluster
Cl0024+16 with existing high-quality Keck spectra for 145 galaxies. A unique
dimension of our Keck data is its spectral resolution, which is high enough to yield
internal kinematics via velocity widths and rotation curves. HST data is essential
to convert the raw kinematic measures into reliable velocities, and to convert these
into masses. This will be the first study of distant cluster disks and their masses
and will thus serve as a powerful discriminant among plausible physical mechanisms
that drive cluster galaxy evolution.
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                                                9555(  1) - 12/06/01 12:57  - [  2]

            Summary Form for Proposal  9555

  Item                         Used in this proposal
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  Proposal Category            AR
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