Globular Cluster Population of Hickson Compact Group 22a and 90c

We present the first measurement of the globular cluster populations ofgalaxies in Hickson compact groups, in order to investigate the effect of thesehigh density environments on the formation and evolution of globular clustersystems. Based on V and R band images that we obtained of HCG 22a and HCG 90cwith the ESO New Technology Telescope (NTT), we find a total globular clusterpopulation of $1590\pm 854$ for HCG 22a and $2136\pm 718$ for 90c. The specificfrequency for HCG 22a was found to be $S_{N}=1.9\pm 1.0$ and $S_{N}= 3.4\pm1.1$ for HCG 90c. A power-law fit to the globular cluster radial profile of HCG22a yields $\sigma\sim R^{-2.01\pm 0.30}$ and for HCG 90c we found $\sigma \simR^{-1.20\pm0.16}$. A comparison of the globular cluster radial profiles withthe surface brightness of the parent galaxy shows that the globular clustersystems are at least as extended as the halo light. The measured values for thespecific frequency are consistent with a scenario in which the host galaxieswere in a low density ``field-like'' environment when they formed theirglobular cluster systems.Comment: 28 pages, 13 figures, 3 tables, accepted for publication in the Astrophysical Journa