The dichotomy of early-type galaxies from their globular cluster systems

TL;DR

This study compares globular cluster systems in faint and bright early-type galaxies, revealing a dichotomy that supports the idea that major mergers influence galaxy evolution.

Contribution

It provides a comparative analysis of over 50 globular cluster systems, highlighting their distinct properties in different galaxy types and linking them to merger histories.

Findings

Globular cluster systems in faint, disky galaxies are unperturbed.

Bright, boxy ellipticals show signs of past mergers.

The properties support a merger-driven dichotomy in early-type galaxies.

Abstract

Growing evidence for the existence of two classes of ellipticals calls for a comparison of the properties of their globular cluster systems. I compiled information on the properties of over 50 globular cluster systems of faint and bright early-type galaxies, and investigated them in the light of the properties of the parent galaxies. The properties of globular cluster systems appear to separate into two classes rather than to follow continuous relations with their host galaxy properties. Globular cluster systems in faint, disky early-type galaxies with unresolved cores appear essentially unperturbed and show no clear signs of a merger past, while systems in bright, boxy ellipticals with resolved cores show all signs expected after a merger event. The globular cluster systems are therefore compatible with the idea that major merger events could be a cause for the dichotomy of early-type galaxies.