5801(  0) - 07/18/95 18:02  - [  1]

    PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS   ST ScI Use Only
                                                       ID:      5801
                                                       Version: **********
                                                       Check-in Date: **********

1.Proposal Title:
Spatial Structures, Kinematics, and Masses of  Faint Galaxies
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2. Scientific Category   3. Proposal For  4. Cycle
Galaxies & Clusters         AR               5
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5. Investigators
                                                                                     Contact?
    PI: David Koo                         Lick Observatory, University of
                                          California, Santa Cruz
   CoI: Garth Illingworth                 Lick Observatory, University of               N
                                          California, Santa Cruz
   CoI: Andrew Phillips                   Lick Observatory, University of               N
                                          California, Santa Cruz

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6. Abstract

We intend to extract detailed structural information for very faint (B <= 24^m)
galaxies from two sets of 4 adjacent V, I WFPC2 images from programs GTO 5090 and
5109.  Each set will span the full length available for multislit work with a single
pointing of the Keck 10-m low-resolution spectrograph. Thus we can efficiently
measure redshifts, emission line ratios, metallicity and age indices, and most
importantly, velocity widths (as appropriate for the brightness and spectral-type)
for ~30 galaxies with each observation. The Keck velocity width data coupled with
the HST sizes will provide an unprecedented opportunity to estimate masses, which
will be used as independent parameters to probe the luminosity evolution of very
faint field galaxies. The high spatial resolution in the two WFPC2 bands is
essential to separate differing evolution of the bulge and disk components. In
principle, the correlations among velocity width, size or surface brightness, and
luminosity are sufficiently tight to untangle evolutionary versus cosmological (q_o)
effects.  This separation is possible because velocity width and surface brightness
are not dependent on q_o, while  velocity width and size should depend only weakly
on evolution. Our team has extensive experience and tools for analyzing the HST
images (developed as part of the  Medium Deep Survey in Cycles 1-4), and equally
important, we have access to Keck to ensure acquisition of the vital spectroscopic
data once the targets are identified from the archive images.
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  Observations Description
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  Real Time Justification
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  Calibration Justification
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  Additional Comments
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  Data Distribution

  Media:           8MM
  Blocking Factor: 10
  Ship To:         PI_Address
  Ship Via:        UPS
  Email:                                                              ,
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                                                5801(  0) - 07/18/95 18:02  - [  3]

            Summary Form for Proposal  5801

  Item                         Used in this proposal
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  Proposal Category            AR
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  Scientific Category          Galaxies & Clusters
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