Globular Clusters around Galaxies in Groups

We have obtained deep photometry of NGC 1199 (in the compact group HCG 22) and NGC 6868 (in the Telescopium loose group) with the Keck II and the ESO VLT-I telescopes. Each galaxy is the optically brightest galaxy of its group. NGC 1199 has two companion galaxies at a median projected distance of only 33 kpc and, based on its peculiar internal structure and large X-ray halo, NGC 6868 has been proposed to be a merger remnant. Our analysis of B and R images uncovered a population of globular clusters around both galaxies, with total (and local) specific frequency SN = 3.6 ± 1.8 (3.4 ± 1.5) for NGC 1199 and SN = 1.8 ± 1.1 (0.8 ± 0.4) for NGC 6868. The radial profile of the globular clusters of NGC 1199 follows the light distribution of the galaxy and can be fitted by a power law and a core model with a very steep slope (α = 2.5 ± 0.3). In the case of NGC 6868, the profile of the globular clusters is well fitted by a power law and a core model profile of slope 1.4 ± 0.3 and is shallower than the galaxy light distribution. Maximum likelihood fitting of two Gaussians to the globular cluster color distribution yields a high significance for multimodality, with peaks centered at (B-R)0 = 1.13 ± 0.04 and 1.42 ± 0.04 (NGC 1199) and (B-R)0 = 1.12 ± 0.07 and 1.42 ± 0.07 (NGC 6868). NGC 1199 and NGC 6868 are good examples of galaxies in which the group environment is likely to have affected their dynamical evolution. We find that for NGC 1199 the properties of the globular cluster system are similar to those for other systems around external elliptical galaxies located in less dense environments but with a very steep radial profile. In the case of NGC 6868, we find a regular radial profile and color distribution and a comparatively low specific frequency for the globular cluster system of the galaxy.