Intermediate old star clusters in a young starburst: the case of NGC 5253

Abstract

We investigate the star cluster population in the outer parts of the starburst galaxy NGC 5253 using archive images taken with the Hubble Space Telescope's Advanced Camera for Surveys. Based on the F415W, F555W and F814W photometry ages and masses are estimated for bona fide star cluster candidates. We find three potentially massive (≥10⁵ M_⊙) star clusters at ages of the order of 1-2 Gyr, implying, if confirmed, a high global star formation rate in NGC 5253 during that epoch. This result underlines earlier findings that the current starburst is just one episode in a very active dwarf galaxy.