On the Evolution of the Globular Cluster Luminosity Function: The Differences

We consider the observational signature of the dynamical effects on theluminosity function of globular clusters. For the three best studied systems,in Milky Way, M31, and M87, there is a statistically significant differencebetween the inner and outer population of globular clusters. In all cases theinner clusters are on average brighter than the outer clusters ($0.26 < \Deltam_0 < 0.84$) and have a smaller dispersion in magnitudes ($0.04 < \Delta \sigma< 0.53$), with the larger differences for the local, better observed samples.The differences are of the type that would be expected if the inner populationhad been depleted by tidal shocks. The results suggest that the innerpopulation suffers substantial evolution from its initial distribution andcannot not be used as a standard candle without correction for dynamicalevolution.