New Tests for Disruption Mechanisms of Star Clusters: The Large and
  Small Magellanic Clouds
  We compare the observed bivariate distribution of masses(M) and ages(t) of
star clusters in the LMC with the predicted distributions g(M,t) from 3
idealized models for the disruption of star clusters: (1)sudden mass-dependent
disruption;(2)gradual mass-dependent disruption; and (3)gradual
mass-independent disruption. The model with mass-{\em in}dependent disruption
provides a good, first-order description of these cluster populations, with
g(M,t) propto M^{beta} t^{gamma}, beta=-1.8+/-0.2 and gamma=-0.8+/-0.2, at
least for clusters with ages t<10^9 yr and masses M<10^3 M_sol (more
specifically, t<10^7(M/10^2 M_sol)^{1.3} yr). This model predicts that the
clusters should have a power-law luminosity function, dN/dL propto L^-1.8, in
agreement with observations. The first two models, on the other hand, fare
poorly when describing the observations, refuting previous claims that
mass-dependent disruption of star clusters is observed in the LMC over the
studied M-t domain. Clusters in the SMC can be described by the same g(M,t)
distribution as for the LMC, but with smaller samples and hence larger
uncertainties. The successful g(M,t) model for clusters in the Magellanic
Clouds is virtually the same as the one for clusters in the merging Antennae
galaxies, but extends the domain of validity to lower masses and to older ages.
This indicates that the dominant disruption processes are similar in these very
different galaxies over at least t<10^8 yr and possibly t<10^9 yr. The mass
functions for young clusters in the LMC are power-laws, while that for ancient
globular clusters is peaked. We show that the observed shapes of these mass
functions are consistent with expectations from the simple evaporation model
presented by McLaughlin & Fall.
