The globular clusters-stellar haloes connection in early-type galaxies

Abstract

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