9194(  1) - 12/20/00 23:38  - [  1]

    PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS   ST ScI Use Only
                                                       ID:      9194
                                                       Version: 1
                                                       Check-in Date: 20-Dec-2000
                                                                      23:29:40

1.Proposal Title:
Galaxy Spectral Energy Distributions at High Redshift
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2. Proposal For  3. Cycle
AR               10
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4. Investigators
                                                                                     Contact?
    PI: Andrew Connolly                   University of Pittsburgh
   CoI: Dr Alexander Szalay               The Johns Hopkins University                  N
   CoI: Dr Istvan Csabai                  Eotvos University                             N
   CoI: Mr Tamas Budavari                 Eotvos University                             N

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5. Abstract

The modeling of galaxy evolution (e.g.\ colors and spectral types) relies on a
detailed understanding of the underlying galaxy spectral energy distributions
(SEDs). Comparison between the colors of galaxies and model SEDs work well for long
lived stellar populations (i.e.\ restframe optical) but break down in the
ultraviolet and near-infrared. This significantly limits our understanding of the
evolution of high redshift galaxies (where the optical passbands sample the
restframe ultraviolet). To alleviate these problems we require a set of SEDs that
can reproduce the observed UV colors of intermediate and redshift galaxies.
Undertaking such a task through spectrophotometric observations would be prohibitive
in terms of telescope time. We have, therefore, developed a technique for extracting
the SEDs of galaxies directly from multicolor photometry. From a pilot study, using
127 HDF galaxies, we have shown we can derive SEDs that better match the colors of
high redshift galaxies than existing SED models. The resolution and accuracy of our
reconstructed SEDs are currently limited by the number of galaxies in the HDF. We
propose here to extend our analysis to >2000 galaxies in the HST archive with
multicolor photometry and published redshifts. We will derive a high resolution set
of SEDs of galaxies at z>0.3 (the high redshift equivalent of the Kennicutt SED
sample) and use these data to quantify the spectral evolution of galaxies.
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                                                9194(  1) - 12/20/00 23:38  - [  2]

            Summary Form for Proposal  9194

  Item                         Used in this proposal
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  Proposal Category            AR
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