8003(  1) - 04/16/98 14:15  - [  1]

    PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS   ST ScI Use Only
                                                       ID:      8003
                                                       Version: 1
                                                       Check-in Date: 16-Apr-1998
                                                                      14:11:31

1.Proposal Title:
Wavelength Dependent Luminosity Functions for Super Star Clusters
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2. Proposal For  3. Cycle
AR               7
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4. Investigators
                                                                                     Contact?
    PI: Catharine Garmany                 University of Colorado
   CoI: Kelsey Johnson                    University of Colorado                        N

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5. Abstract

Starburst galaxies, considered to exhibit enhanced star formation on a galaxy-wide
scale, have now been found with HST to contain very intense knots of star formation,
referred to as ``super star clusters'', or SSCs. A steepening of the luminosity
function with increasing wavelength for young burst populations, such as SSCs, has
recently been predicted by Hogg & Phinney (1997). This prediction, not previously
addressed in the literature, is straightforward to test with multi- wavelength
photometry. Using the colors of the SSCs in a galaxy in combination with the
difference in slopes of the luminosity functions derived from different wavelength
bands and applying population synthesis models, we can also constrain the high mass
stellar initial mass function (IMF). Recent work has suggested that the slope of the
IMF is roughly constant in a variety of local environments, from galactic OB
associations to the closest analog of a super star cluster, R136 in the LMC. This
investigation will allow us to compare the IMFs in the extreme environments of SSCs
in starburst galaxies to IMFs found locally in the Galaxy, LMC, and SMC. Archival
imaging data in both the UV and optical bands is available for about 10 young
starburst systems. These data will allow us to test the predictions of Hogg &
Phinney, as well as constrain the IMF for environments not found in the nearby
universe.
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  Data Distribution

  Media:           ELECTRONIC
  Blocking Factor: 10
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                                                8003(  1) - 04/16/98 14:15  - [  2]

            Summary Form for Proposal  8003

  Item                         Used in this proposal
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  Proposal Category            AR
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