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C. J. Grillmair (SIRTF Science Center/Caltech), G. H. Smith (UCO/Lick Observatory)
A low mass, large core radius, and a low central concentration suggest that the globular cluster Palomar 5 lost a large fraction of its initial mass at some point in the past. If the dynamical evolution of Palomar 5 has been dominated by the effects of mass loss, then theoretical arguments suggest that the luminosity function should be deficient in low-mass stars. Using deep WFPC2 F555W and F814W photometry, we determine the main sequence luminosity function both near the cluster center and in a field beyond the half-light radius. The turnoff occurs at V ~ 20.6, and the main sequence can be followed to V ~ 26 before merging with field objects down to the limiting magnitude of V ~27. We compare the luminosity functions in the two fields with one another, and with that of Omega Cen, to search for evidence of a low mass cutoff and/or mass segregation within the cluster. This research is supported in part by STScI grant GO-06788.
The author(s) of this abstract have provided an email address for comments about the abstract: carl@ipac.caltech.edu