Hubble Space Telescope Imaging of Globular Clusters in Two Face-On Low Surface Brightness Galaxies UGC 5981 and UGC 6614

Abstract

We present a study searching for globular cluster systems (GCSs) of two face-on low surface brightness galaxies (LSBGs), UGC 5981 and UGC 6614. Based on HST WFPC2 images of F555W and F814W filters, we detect 12 and 18 GC candidates for UGC 5981 and UGC 6614, respectively. Although these two LSBGs have very different bulge properties, they have very similar specific frequencies (SN) of 0.1. However, SN ~ 0.1 is quite small even for their late morphological types, albeit within errors. This suggests that LSBGs have had star formation histories lacking dominant initial starburst events while accumulating their stellar masses through sporadic star formation activities.