Star clusters in the nearby late-type galaxy NGC 1311

Ultraviolet, optical and near-infrared images of the nearby (D 5.5 Mpc) SBm galaxy NGC 1311, obtained with the Hubble Space Telescope, reveal a small population of 13 candidate star clusters. We identify candidate star clusters based on a combination of their luminosity, extent, and spectral energy distribution. The masses of the cluster candidates range from 10³ M_☉ up to 10⁵ M_☉, and show a strong positive trend of larger mass with increasing with cluster age. Such a trend follows from the fading and dissolution of old, low-mass clusters, and the lack of any young super-star clusters of the sort often formed in strong starbursts. The cluster age distribution is consistent with a bursting mode of cluster formation, with active episodes of age ~10 Myr, ~100 Myr, and  Gyr. The ranges of age and mass we probe are consistent with those of the star clusters found in quiescent Local Group dwarf galaxies.