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Description
We present the results obtained from an objective search for stellar clusters, both in the currently active nuclear starburst region, and in the poststarburst disk of M82. Images obtained with the Advanced Camera for Surveys (ACS) on board the Hubble Space Telescope (HST) in F435W (B), F555W (V), and F814W (I) filters were used in the search for the clusters. We detected 653 clusters, of which 393 are located outside the central 450pc in the poststarburst disk of M82. The luminosity function of the detected clusters shows an apparent turnover at B=22mag (M_B_=-5.8), which we interpret from Monte Carlo simulations as due to incompleteness in the detection of faint clusters, rather than an intrinsic lognormal distribution. We derived a photometric mass of every detected cluster from models of simple stellar populations assuming a mean age of either 8 (nuclear clusters) or 100 (disk clusters) million years old. The mass functions of the disk (older) and the nuclear (younger) clusters follow power laws, the former being marginally flatter ({alpha}=1.5+/-0.1) than the latter ({alpha}=1.8+/-0.1). The distribution of sizes (FWHM) of clusters brighter than the apparent turnover magnitude (mass>~2x10^4^M_{sun}_) can be described by a lognormal function.
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