Globular cluster population of Hickson compact group 22a and 90c

We present the first measurement of the globular cluster populations of galaxies in Hickson compact groups, in order to investigate the effect of these high-density environments on the formation and evolution of globular cluster systems. Based on V- and R-band images that we obtained of HCG 22a and HCG 90c with the ESO New Technology Telescope (NTT), we find a total globular cluster population of 1590 +/- 854 for HCG 22a and 2136 +/- 718 for 90c. The specific frequency was found to be S-N = 1.9 +/- 1.0 for HCG 22a and S-N = 3.4 +/- 1.1 for HCG 90c. A power-law fit to the globular cluster radial profile of HCG 22a yields sigma similar to R-2.01 +/- 0.30, and for HCG 90c we found sigma similar to R-1.20 +/- 0.16. A comparison of the globular cluster radial profiles with the surface brightness of the parent galaxy shows that the globular cluster systems are at least as extended as the halo light. The measured values for the specific frequency are consistent with a scenario in which the host galaxies were in a low-density "field-like" environment when they formed their globular cluster systems.