DEEP HUBBLE-SPACE-TELESCOPE OBSERVATIONS OF STAR-CLUSTERS IN NGC-1275

We present an analysis of compact star clusters in deep Hubble Space T elescope Wide Field Planetary Camera 2 images of NGC 1275. B- and R-ba nd photometry of roughly 3000 clusters shows a bimodality in the B-R c olors, suggesting that distinct old and young cluster populations are present. The small spread in the colors of the blue clusters is consis tent with the hypothesis that they are a single-age population, with a n inferred age of 0.1 to 1 Gyr. The luminosity function shows increasi ng numbers of blue clusters to the limit of our photometry, which reac hes several magnitudes past the turnover predicted if the cluster popu lation is identical to current Galactic globular clusters seen at a yo unger age. The blue clusters have a spatial distribution that is more centrally peaked than that of the red clusters. The individual cluster s are slightly resolved, with core radii less than or similar to 0.75 pc if they have modified Hubble profiles. We estimate the specific fre quencies of the old and young populations and discuss the uncertaintie s in these estimates. We find that the specific frequency of the young population in NGC 1275 is currently larger than that of the old popul ation and will remain so as the young population evolves, even if the majority of the low-mass clusters are eventually destroyed. If the you ng population formed during a previous merger, this suggests that merg ers can increase the specific frequency of globular clusters in a gala xy. However, the presently observed young population likely contains t oo few clusters to have a significant impact on the overall specific f requency as it will be observed in the future.