Bright star clusters in the antennae analyzed with evolutionary synthesis

The Antennae galaxies (NGC 4038/39) are a pair of relatively nearby (D ~ 19 Mpc for H0 = 75) gas-rich spirals of comparable mass in the process of merging with extensive dynamical and evolutionary synthesis modelling available. With HSTWFPC1 Whitmore & Schweizer (1995) (WS95) detected 738 bright Young Star Clusters (YSCs) around the Antennae. YSCs have been detected in many interacting and starbursting galaxies, but the YSC system in the Antennae is the most populous one, well defining an exponential Luminosity Function (LF) over more than 5 mag above the completeness limit. Problems arising from crowding of the YSCs on a bright and variable galaxy background and from the PSF of WFPC1 may cause blending of YSCs and an overestimation of their effective radii.