2001AJ....121.1482B

We combine our compilation of photometry of M31 globular clusters and probable cluster candidates with new near-infrared photometry for 30 objects. Using these data we determine the globular cluster luminosity function (GCLF) in multiple filters for the M31 halo clusters. We find a GCLF peak and dispersion V⁰₀=16.84±0.11, σ_t=0.93±0.13 (Gaussian σ=1.20±0.14), consistent with previous results. The halo GCLF peak colors (e.g., B⁰₀-V⁰₀) are consistent with the average cluster colors. We also measure V-band GCLF parameters for several other subsamples of the M31 globular cluster population. The inner third of the clusters have a GCLF peak significantly brighter than that of the outer clusters (ΔV⁰~0.5 mag). Dividing the sample by both galactocentric distance and metallicity, we find that the GCLF also varies with metallicity, as the metal-poor clusters are on average 0.36 mag fainter than the metal-rich clusters. Our modeling of the catalog selection effects suggests that they are not the cause of the measured GCLF differences, but a more complete, less contaminated M31 cluster catalog is required for confirmation. Our results imply that dynamical destruction is not the only factor causing variation in the M31 GCLF: metallicity, age, and cluster initial mass function may also be important.