2001/10/18 by Carl J. Grillmair, Graeme H. Smith · 1 citation
Physics and Astronomy · #Advanced Camera for Surveys #Astronomy #Astronomy and Astrophysical Research #Astrophysics #Astrophysics and Star Formation Studies #Galaxy #Globular cluster #Hubble space telescope #Initial mass function #Luminosity #Luminosity function #Main sequence #Mass segregation #Mass-to-light ratio #Photometry (optics) #Physics #Star cluster #Star formation #Stars #Stellar mass #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1086/323916
19 LaTeX/AASTeX pages with 8 figures, accepted for publication in the Astronomical Journal
arxiv created 2001/10/18 · openalex publication_date 2001/12/01 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
A low mass, large core radius, low central concentration, and strong tidal tails suggest that the globular cluster Palomar 5 has lost a large fraction of its initial mass over time. If the dynamical evolution of Pal 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 functions both near the cluster center and in a field near the half-light radius. A comparison of these luminosity functions yields no compelling evidence of mass segregation within the cluster, in accord with expectations for low-concentration clusters. On the other hand, a comparison of the global mass function of Pal 5 with that of ω Cen and M55 indicates an increasing deficiency of stars with progressively lower masses. A fit of the observed luminosity function to theoretical models indicates a mass function for Pal 5 of dN / dm ∝ m -0.5 , which is notably more deficient in low-mass stars than other globular clusters that have been studied with the Hubble Space Telescope . The flatness of the mass function is consistent with models of the dynamical evolution of globular clusters that have lost ∼90% of their original stellar mass. We suggest that, like NGC 6712, Pal 5 has lost a large percentage of its original stellar content as a result of tidal shocking.