A nearby repeating fast radio burst in the direction of M81
  We report on the discovery of FRB 20200120E, a repeating fast radio burst
(FRB) with low dispersion measure (DM), detected by the Canadian Hydrogen
Intensity Mapping Experiment (CHIME)/FRB project. The source DM of 87.82 pc
cm$^{-3}$ is the lowest recorded from an FRB to date, yet is significantly
higher than the maximum expected from the Milky Way interstellar medium in this
direction (~ 50 pc cm$^{-3}$). We have detected three bursts and one candidate
burst from the source over the period 2020 January-November. The baseband
voltage data for the event on 2020 January 20 enabled a sky localization of the
source to within $\simeq$ 14 sq. arcmin (90% confidence). The FRB localization
is close to M81, a spiral galaxy at a distance of 3.6 Mpc. The FRB appears on
the outskirts of M81 (projected offset $\sim$ 20 kpc) but well inside its
extended HI and thick disks. We empirically estimate the probability of chance
coincidence with M81 to be $< 10^{-2}$. However, we cannot reject a Milky Way
halo origin for the FRB. Within the FRB localization region, we find several
interesting cataloged M81 sources and a radio point source detected in the Very
Large Array Sky Survey (VLASS). We searched for prompt X-ray counterparts in
Swift/BAT and Fermi/GBM data, and for two of the FRB 20200120E bursts, we rule
out coincident SGR 1806$-$20-like X-ray bursts. Due to the proximity of FRB
20200120E, future follow-up for prompt multi-wavelength counterparts and
sub-arcsecond localization could be constraining of proposed FRB models.
