FRB20210630A found by UTMOST

ATel #14745; A. Mandlik (Swinburne University of Technology, "SUT"), M. Bailes (SUT), A. Deller (SUT), C. Flynn (SUT), V. Gupta (SUT), A. Jameson (SUT), T. Bateman (SUT), D. Campbell-Wilson (USyd), C. Day (SUT), W. Farah (University of California, Berkeley), A. J. Green (USyd), M. E. Lower (SUT), D. C. Price (SUT), A. Sutherland (USyd), G. Torr (SUT), G. Urquhart (SUT), V. Venkatraman Krishnan (Max-Planck-Institut fuer Radioastronomie)
on 1 Jul 2021; 09:19 UT
Credential Certification: Vivek Gupta (vivekgupta@swin.edu.au)

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At UTC 2021-06-30-12:48:11.2 (2021-06-30.533462963), we found a fast radio burst as part of the ongoing search program at the Molonglo telescope (UTMOST).

Molonglo is a 1.6 km long East-West array (Bailes et al 2017, PASA, 34, 45) and was operating in drift-scan mode, pointing at the meridian at the time of detection. Source localisation is excellent in Right Ascension (5 arcsec at 1-sigma) but poor in Declination (~1.2 deg at 1-sigma) (see Caleb et al 2017 MNRAS 468, 3746).

FRB20210630A was found during a blind FRB search programme in real-time using an automated GPU-accelerated/machine learning-based pipeline and the raw voltages were recorded for offline processing.

The optimal dispersion measure (DM) that maximizes the signal-to-noise ratio is: 943.7 pc cm^-3. The DM estimate of NE2001 model is ~78.7 pc cm^-3, and YMW16 model is ~59.7 pc cm^-3 at this position, resulting in an intergalactic excess of ~865 pc cm^-3. The upper limit on the DM-inferred redshift is thus z ~ 0.87.

An early estimate (lower limit) of the event's apparent fluence is ~60.14 Jy ms (corrected for attenuation of the primary beam in the RA direction, but not in the Dec direction), with a detection signal-to-noise ratio = 10.

The most likely position is RA = 17:23:07.4, DEC =+07:51:42, J2000, Gl = 29.9356 deg, Gb = 23.1882 deg. The 95% confidence localisation arc is as follows: (RA, DEC) in (hours, deg)

17.384378 5.300861
17.384511 5.661528
17.384650 6.022194
17.384789 6.382861
17.384933 6.743556
17.385078 7.104222
17.385225 7.464889
17.385375 7.825556
17.385531 8.186222
17.385686 8.546889
17.385844 8.907556
17.386006 9.268222
17.386169 9.628917
17.386336 9.989583
17.386506 10.35025

A formula describing the localisation arc is:

RA = 17.385376 + 4.22212*e-4(DEC - 7.825551) + 1.024401e-5*(DEC - 7.825551)**2

where RA is in hours, Dec is in deg, and is valid in the range Dec= [5.3,10.35]

For the dynamic spectra, and the localisation plots, follow this link.

Follow-up observations of the FRB are encouraged.