Scaling relations for globular cluster systems in early-type galaxies

TL;DR

This study investigates the scaling relations of globular cluster systems in early-type galaxies using HST data, revealing correlations with galaxy properties and comparisons with simulations.

Contribution

It provides new empirical relations between GCS properties and galaxy/halo characteristics, supported by a combined observational and simulation analysis.

Findings

GCS radial profile properties correlate with galaxy stellar mass and size.

Extension of GCS correlates with halo virial radius.

Good agreement between observations and numerical simulations.

Abstract

The formation and growth of globular cluster systems (GCSs) is closely related to the evolutionary processes experienced by their host galaxies. In particular, their radial distributions scale with several properties of the galaxies and their halos. We performed a photometric study, by means of HST/ACS archival data of several intermediate luminosity galaxies located in low density environments. It was supplemented with available photometric data of GCSs from the Virgo and Fornax clusters, resulting in a sample of almost 30 GCSs for which we fitted their radial profiles. The resulting overall properties agree with those from previous studies, as we found that the effective radius, extension and concentration of the GCS radial profiles correlate with the stellar mass, effective radius and number of globular clusters, presenting in some cases a bilinear relation. The extension also correlates with the central velocity dispersion for central galaxies, but not for satellites. From a statistical comparison with numerical simulations we obtained good agreement between the effective radius and extension of the GCS scale with the effective and virial radius of the halos, respectively. Finally, we analysed these results in the literature context.