Sub-arcminute localization of 13 repeating fast radio bursts detected by CHIME/FRB

We report on improved sky localizations of thirteen repeating fast radio bursts (FRBs) discovered by CHIME/FRB via the use of interferometric techniques on channelized voltages from the telescope. These so-called ‘baseband localizations’ improve the localization uncertainty area presented in past studies by more than three orders of magnitude. The improved localization regions are provided for the full sample of FRBs to enable follow-up studies. The localization uncertainties, together with limits on the source distances from their dispersion measures (DMs), allow us to identify likely host galaxies for two of the FRB sources. FRB 20180814A lives in a massive passive red spiral at z ∼ 0 . 068 with very little indication of star formation, while FRB 20190303A resides in a merging pair of spiral galaxies at z ∼ 0 . 064 undergoing signiﬁcant star formation. These galaxies show very diﬀerent characteristics, further conﬁrming the presence of FRB progenitors in a variety of environments even among the repeating sub-class.