10987(  1) - 04/03/06 11:24  - [  1]

                  HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 10987

Version: 1    Check-in Time: 03-Apr-2006 15:24:00

Title
Novel Analysis of Stellar Populations and Constraints on Galaxy Evolution
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Type             Cycle     Parallel Pointing Tolerance
AR               15        <none>
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Investigators
                                                                                     Contact?
    PI: Prof. Dennis Zaritsky             University of Arizona
   CoI: Dr. Jason Harris                  University of Arizona                         N

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Abstract

We propose to utilize HST archival data to develop a new method for the
reconstruction of star formation histories of galaxies at all redshifts. In
particular, using ground-based and HST archival data we will develop a method that
is based on the distribution of pixel values rather than stellar photometry. This
new conceptual appropach accesses data below an image's limiting magnitude and does
not introduce many of the uncertainties inherrent in crowded-field photometry. Both
will lead to significantly tighter constraints on the ancient star formation
history. Comparing the results of this technique applied to the ground-based images
with the results of the standard method on HST color-magnitude diagrams will
validate (or not) the specific algorithms we develop. Once we have developed a
succcessful technique it can be applied to HST data of galaxies in the nearby
universe (for example, HST images of M 33 are comparable to our ground-based images
of the LMC). By varying the angular pixel scale in the analysis we will be able to
produce internally self-consistent analyses of star formation histories at all
redshifts. For the nearby universe this technique maximizes the information
extracted from the existing imaging - for the distant universe in enables direct
comparison to the local star formation histories. We will make the algorithm(s)
public, as we have done with our more classical star formation reconstruction code,
StarFISH.
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