ASKAP localisation of the FRB 20201124A source

ATel #14515; C. K. Day (Swinburne University of Technology, SUT), S. Bhandari (CSIRO), A. T. Deller (SUT), R. M. Shannon (SUT), V. A. Moss (CSIRO), on behalf of the ASKAP-CRAFT survey science project
on 6 Apr 2021; 12:50 UT
Credential Certification: Ryan Shannon (rms72@cornell.edu)

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Here we report on further analysis and follow up of the FRB20201124A source (ATel #14497) with the Australian Square Kilometre Array Pathfinder (ASKAP) as part of the ASKAP-CRAFT survey science project.

When ASKAP detected repeat bursts from the source (ATel #14502, ATel #14508), voltage data from buffers from individual antennas were triggered and downloaded. This enabled interferometric localisation of the burst, using methods described in Bannister et al. (2019, Science, 365, 565). The position reported here is from the second burst detected by ASKAP in the higher 1.3-GHz band (ATel #14508).

The burst was localised to the following best-fit position (epoch J2000):
RA: 05:08:03.662
DEC: +26:03:39.82
The total uncertainty in the burst position comprises a statistical component (dependent on the S/N of the FRB image) and a systematic component related to the uncertainty of the astrometric frame registration. The reference frame correction, and its associated uncertainty, were derived by comparing positions of continuum sources detected in the 3-s voltage download containing the FRB) with catalogue counterparts, in this case from the NVSS (Condon et al. 1999, AJ, 115,1693). Currently, the systematic uncertainty dominates the total, but the position and its uncertainty may be refined if more precise positions for the continuum sources in the field surrounding the FRB are determined, or as additional bursts from this source are analyzed. We currently estimate the total uncertainty to be less than 1 arcsec for each coordinate.

The burst is spatially coincident with a galaxy cataloged in the Sloan Digital Sky Survey photometric survey, SDSS J050803.48+260338.0. The galaxy has a catalogued photometric redshift of z=0.08+/- 0.02, as calculated using the kd-tree nearest-neighbor fit algorithm (Ahumada et al, submitted to ApJS; arXiv:1912.02905). The galaxy is also catalogued in the first Pan-STARRS data release with a reported photometric redshift of z=0.105 (Beck et al. 2020, MNRAS, 500,1633). Further analysis with refined astrometry will be used to quantify the chance coincidence.

We encourage multi-wavelength follow-up of the host galaxy of the FRB20201124A source while it remains in its current active phase.