7976(  1) - 04/16/98 14:03  - [  1]

    PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS   ST ScI Use Only
                                                       ID:      7976
                                                       Version: 1
                                                       Check-in Date: 16-Apr-1998
                                                                      14:01:59

1.Proposal Title:
A Morphological and Multicolor Survey for Ultrafaint QSOs/AGNs
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2. Proposal For  3. Cycle
AR               7
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4. Investigators
                                                                                     Contact?
    PI: Scott Anderson                    University of Washington
   CoI: Bernhard Beck-Winchatz            University of Washington                      N

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5. Abstract

Measuring the populous faint end of the luminosity function is crucial for
constraining the global evolution of QSOs/AGNs; and yet such objects are
frustratingly dim, with m~24 at modest to high redshift. Although multicolor surveys
have been undertaken for ultrafaint QSOs using groundbased CCD searches alone, due
to seeing limitations such samples suffer strong morphological contamination by
faint compact galaxies. Fortunately the HST archive includes a large and reasonably
homogeneous collection of deep red WFPC2 images in high galactic latitude fields,
and the ~ 0.1'' spatial resolution of these images permits an exquisite opportunity
for the morphological selection of a sample of ultrafaint objects with stellar PSFs
(e.g., stars and QSOs), as well as galaxies with stellar-PSF cores (e.g., Seyferts
and low-z QSOs). We have taken complementary deep groundbased UV/blue CCD images in
45 such archival red WFPC2 fields, including the ``Groth-Westphal Strip". We propose
an archival analysis program that combines the multicolor photometric information
(red WFPC2, and our UV/blue groundbased data), with the extraordinary spatial
resolution of the HST images, to obtain a morphological and multicolor survey for
ultrafaint QSOs/AGNs to m~24. A quick look at a portion of these data confirms the
viability of our approach, and yields a lower surface density of ultrafaint QSO
candidates than found in groundbased surveys, although definitive results require
more sophisticated reductions/analyses.
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  Data Distribution

  Media:           ELECTRONIC
  Blocking Factor: 10
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                                                7976(  1) - 04/16/98 14:03  - [  2]

            Summary Form for Proposal  7976

  Item                         Used in this proposal
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  Proposal Category            AR
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