8750(  1) - 12/30/99 13:03  - [  1]

    PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS   ST ScI Use Only
                                                       ID:      8750
                                                       Version: 1
                                                       Check-in Date: 30-Dec-1999
                                                                      12:31:47

1.Proposal Title:
The Fundamental Plane of Cluster Dwarf Ellipticals
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2. Proposal For  3. Cycle
AR               9
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4. Investigators
                                                                                     Contact?
    PI: Rafael Guzman                     Yale University

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5. Abstract

We propose to use archival WFPC2 images to measure the structural parameters (i.e.,
luminosity profile, half-light radius, surface brightness, and concentration
indices) of dwarf ellipticals (dEs) in the Coma cluster. This proposal is part of a
comprehensive program to study the scaling laws of cluster dEs. These empirical
correlations provide key constrains to models of galaxy fomation and evolution.
Compared to other studies of cluster dEs, this program is unique in that it includes
measurements of the internal kinematics (i.e., velocity dispersions). Colors,
magnitudes, redshifts, line strengths and velocity dispersions for ~80 dEs in the
central 24'*18' region of Coma have already been measured from deep UBR images and
multiobject spectroscopy using WIYN. In addition to these data, structural
parameters are essential to explore fundamental plane-type correlations. Given the
small size of faint dEs (~0.4'' at Coma), high spatial resolution images are
required to measure their structural parameters. There are 61 archival WFPC2
pointings (mostly in F606W filter) which provide good signal-to-noise images of ~21
dEs in our sample. This combined WIYN/HST data set will allow the first
determination of the fundamental plane of cluster dEs, and aims to be a milestone
for testing current theories on the formation and evolution of dwarf galaxies in
clusters.
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                                                8750(  1) - 12/30/99 13:03  - [  2]

            Summary Form for Proposal  8750

  Item                         Used in this proposal
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  Proposal Category            AR
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