Bright Young Star Clusters in NGC5253 with LEGUS

Using UV-to-H broad and narrow-band HST imaging, we derive the ages and masses of the 11 brightest star clusters in the dwarf galaxy NGC5253. This galaxy, located at~ 3 Mpc, hosts an intense starburst, which includes a centrally-concentrated dusty region with strong thermal radio emission (theradio nebula'). The HST imaging includes data from the Cycle 21 Treasury Program LEGUS (Legacy ExtraGalactic UV Survey), in addition to narrow--band H-alpha (6563 A), P-beta (12820 A), and P-alpha (18756 A). The bright clusters have ages~ 1-15 Myr and masses~ 1E4-2.5 E5 Msun. Two of the 11 star clusters are located within the radio nebula, and suffer from significant dust attenuation. Both are extremely young, with a best-fit age around 1 Myr, and masses~ 7.5 E4 and~ 2.5 E5 Msun, respectively. The most massive of the tworadio nebula'clusters is 2-4 times less massive than previously estimated and is …