The Relation Between the Globular Cluster Mass and Luminosity Functions

TL;DR

This paper explores the relationship between the luminosity and mass functions of globular clusters, highlighting how mass-to-light ratio variations influence their observed distributions and modeling their initial conditions.

Contribution

It introduces a model linking the globular cluster luminosity function to the mass function, accounting for variable mass-to-light ratios and initial mass distributions.

Findings

Mass-to-light ratio increases with cluster mass and luminosity.

Power law slopes of GCLF and GCMF inherently differ due to M/L variability.

Observed GCLF aligns with a Schechter initial mass function and mass-dependent mass loss.

Abstract

The relation between the globular cluster luminosity function (GCLF, dN/dlogL) and globular cluster mass function (GCMF, dN/dlogM) is considered. Due to low-mass star depletion, dissolving GCs have mass-to-light (M/L) ratios that are lower than expected from their metallicities. This has been shown to lead to an M/L ratio that increases with GC mass and luminosity. We model the GCLF and GCMF and show that the power law slopes inherently differ (1.0 versus 0.7, respectively) when accounting for the variability of M/L. The observed GCLF is found to be consistent with a Schechter-type initial cluster mass function and a mass-dependent mass-loss rate.