The Disruption Time of Clusters in Selected Regions of Four Galaxies

Abstract

If the cluster formation rate is constant and the disruption time ofclusters depends on their initial mass as t_dis = t_4 {\times} (M_cl/10^4M\_{\sun})^{γ}, the values of t _{4} and {γ} can bederived in a very simple way from the age and mass histograms of largehomogeneous samples of clusters with reliable age and/or massdeterminations. We demonstrate the method and derive the values of t_{4} and {γ} from cluster samples in selected fields of fourgalaxies: M51, M33, SMC and the solar neighbourhood. The values of{γ} are the same within their uncertainties in the four galaxieswith {\lt} {γ} {\gt} = 0.62 {\plusmn} 0.06. However, the disruptiontime t _{4} of clusters of 10^4 M\_{\sun} is very different inthe different locations. It is shortest in the inner region of M51 ( t_{4} = 4 x 10^{7} yrs) and highest in the SMC ( t_{4} = 4 x 10^{9} yrs).