The self-enrichment of galactic halo globular clusters

The mass-metallicity relation

¹ Institute of Astrophysics and Geophysics, University of Liège, avenue de Cointe 5, 4000 Liège, Belgium
² Institute of Astronomy, Madingley Road, Cambridge CB3 0HA, UK

Corresponding author: G. Parmentier, parmentier@astro.ulg.ac.be

Received: 10 July 2001
Accepted: 16 August 2001

Abstract

We discuss the existence of a mass-metallicity relation among galactic halo globular clusters. The lack of any luminosity-metallicity correlation in globular cluster systems has been used as an argument against self-enrichment models of cluster formation. We show that such a relation is statistically present among the galactic Old Halo globulars. This observational correlation implies that the least massive old clusters are the most metal-rich. This is in contradiction with the idea that, if globular clusters were self-enriched systems, the most metal-rich clusters would also be the most massive ones. We further show that this anti-correlation is as predicted by self-enrichment models.