Mass distribution averaged over the indicated intervals of age for the Antennae clusters (data points) and for Model 1 (lines). In this model, clusters have a power-law initial mass function, a constant formation rate, and sudden mass-dependent disruption. The dashed and solid lines were computed for the younger and older clusters, respectively, from Equations (7), (B1), and (B2) with τ _* = 5 × 10 ⁷ yr and k = 0.62.