An optical/near-infrared survey of GCs in early-type galaxies

TL;DR

This study presents optical and near-infrared observations of globular cluster systems in 14 early-type galaxies, examining colour bimodality and age distributions to understand their formation histories.

Contribution

It provides new multi-wavelength data and analysis that challenge previous claims about colour bimodality being an artifact, and explores age distributions using combined optical and near-infrared colours.

Findings

Evidence supporting or refuting the colour bimodality hypothesis.

Insights into the age distributions of globular clusters.

Analysis of the impact of horizontal branch morphology on colour-metallicity relations.

Abstract

Optical/near-infrared observations for 14 globular cluster (GC) systems in early- type galaxies are presented. We investigate the recent claims (Yoon, Yi & Lee 2006) of colour bimodality in GC systems being an artefact of the non linear colour - metallicity transformation driven by the horizontal branch morphology. Taking the advantage of the fact that the combination of optical and near-infrared colours can in principle break the age/metallicity degeneracy we also analyse age distributions in these systems.