7543(  1) - 12/14/96 00:54  - [  0]

    PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS   ST ScI Use Only
                                                       ID:      7543
                                                       Version: 1
                                                       Check-in Date: 13-Dec-1996
                                                                      18:20:44

1.Proposal Title:
The Surface Brightness Fluctuations and Globular Cluster Populations of Virgo
Ellipticals
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2. Scientific Category   3. Proposal For  4. Cycle
COSMOLOGY                   AR               7
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5. Investigators
                                                                                     Contact?
    PI: Zlatan Tsvetanov                  Johns Hopkins University
   CoI: Eric Neilsen, Jr.                 Johns Hopkins University                      N
   CoI: Holland Ford                      Johns Hopkins University                      N

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6. Abstract

WFPC-2 images of elliptical and lenticular galaxies provide a wealth of information
about the galaxy, not all of which is always explored by the investigators who
originally took the image. In particular, the surface brightness fluctuations (SBF)
in the images can be used both as a measurement of distance, and possibly as an aid
for the study of stellar populations. In addition, the study of the luminosity
function and specific frequency of globular clusters has implications both for
galaxy formation processes and the distance. Suitable images for at least fourteen
Virgo galaxies are contained in the archive, which will allow us to study the shape
of the Virgo cluster using depth measurements determined from SBF, to compare HST
SBF measurements with those obtained from the ground, and to study if and how the
characteristic of the globular cluster populations vary with position in this
cluster. A few galaxies in the Fornax cluster, which will become available over the
next year, and additional galaxies from the archive also will be analyzed. We have
performed such an analysis of the SBF and globular clusters in NGC4478, a close
companion of M87, using WFPC2 parallel images. In doing so, we have developed an SBF
method better suited to the undersampled PSF of the WFPC-2 than the method more
traditionally used with images from ground based telescopes. We also have developed
an understanding of the process required for the globular cluster analysis.
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  Data Distribution

  Media:           ELECTRONIC
  Blocking Factor: 10
  Ship To:         PI_Address
  Ship Via:
  Email:                                                              ,
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                                                7543(  1) - 12/14/96 00:54  - [  1]

            Summary Form for Proposal  7543

  Item                         Used in this proposal
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  Proposal Category            AR
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  Scientific Category          COSMOLOGY
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