Deep Synoptic Array Science: Discovery of the Host Galaxy of FRB 20220912A

We report the detection and interferometric localization of the repeating fast radio burst (FRB) source FRB 20220912A during commissioning observations with the Deep Synoptic Array (DSA-110). Two bursts were detected from FRB 20220912A, one each on 2022 October 18 and 2022 October 25. The best-fit position is (R.A. J2000, decl. J2000) = (23:09:04.9, +48:42:25.4), with a 90% confidence error ellipse with radii +/- 2 '' and +/- 1 '' in R.A. and decl., respectively. The two bursts are polarized, and we find a Faraday rotation measure that is consistent with the low value of +0.6 rad m(-2) reported by CHIME/FRB. The DSA-110 localization overlaps with the galaxy PSO J347.2702+48.7066 at a redshift z = 0.0771, which we identify as the likely host. PSO J347.2702+48.7066 has a stellar mass of approximately 10(10) M (circle dot), modest internal dust extinction, and a star formation rate likely in excess of 0.1 M (circle dot) yr(-1). The host-galaxy contribution to the dispersion measure is likely less than or similar to 50 pc cm(-3). The FRB 20220912A source is therefore likely viewed along a tenuous plasma column through the host galaxy.

Automated summary

We detected and localized the repeating FRB source FRB 20220912A using the DSA-110. Two bursts were observed on October 18 and October 25, 2022. The best-fit position is (R.A. J2000, decl. J2000) = (23:09:04.9, +48:42:25.4), with a 90% confidence error ellipse. The source is likely viewed through a tenuous plasma column in the host galaxy PSO J347.2702+48.7066.