The globular clusters-stellar haloes connection in early type galaxies

TL;DR

This study investigates the link between globular cluster systems and stellar populations in early type galaxies, revealing correlations with galaxy mass, metallicity, and formation efficiency, based on Virgo cluster data.

Contribution

It extends previous methods to analyze globular cluster and stellar population connections in early type galaxies using Virgo data, highlighting formation efficiency and metallicity trends.

Findings

Integrated galaxy colours match within uncertainties

Mass to luminosity ratios are consistent with literature

Most globular cluster systems form a thick plane in parameter space

Abstract

This paper explores if, and to what an extent, the stellar populations of early type galaxies can be traced through the colour distribution of their globular cluster systems. The analysis, based on a galaxy sample from the Virgo ACS data, is an extension of a previous approach that has been successful in the cases of the giant ellipticals NGC 1399 and NGC 4486, and assumes that the two dominant GC populations form along diffuse stellar populations sharing the cluster chemical abundances and spatial distributions. The results show that a) Integrated galaxy colours can be matched to within the photometric uncertainties and are consistent with a narrow range of ages; b) The inferred mass to luminosity ratios and stellar masses are within the range of values available in the literature; c) Most globular cluster systems occupy a thick plane in the volume space defined by the cluster formation efficiency, total stellar mass and projected surface mass density. The formation efficiency parameter of the red clusters shows a dependency with projected stellar mass density that is absent for the blue globulars. In turn, the brightest galaxies appear clearly detached from that plane as a possible consequence of major past mergers; d) The stellar mass-metallicity relation is relatively shallow but shows a slope change at $M_*\approx 10^{10} M_\odot$. Galaxies with smaller stellar masses show predominantly unimodal globular cluster colour distributions. This result may indicate that less massive galaxies are not able to retain chemically enriched intestellar matter.