Two new FRBs in the FRB190711 field detected at Parkes

ATel #14040; Vivek Gupta (Swinburne University of Technology "SUT"), Andrew Jameson (SUT), Chris Flynn (SUT), Daniel C. Price (Curtin University), Dougal Dobie (University of Sydney), Jeff Cooke (SUT), Jielai Zhang (SUT), Sara Webb (SUT), Simon Goode (SUT)
on 24 Sep 2020; 10:29 UT
Distributed as an Instant Email Notice Transients
Credential Certification: Vivek Gupta (vivekgupta@swin.edu.au)

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The Deeper Wider Faster (DWF) project (e.g., Andreoni and Cooke, 2019, IAUS, 339, 135) detected two new fast radio bursts (FRBs) with the Parkes Radio telescope while observing at 1.4 GHz using the 21-cm multibeam receiver (Staveley-Smith et al. 1996, PASA, 13, 243). Both FRBs were detected while observing FRB190711 (C. K. Day et al, 2020) positioned at the center of Beam 01. FRB190711 has a Dispersion Measure (DM) = 593.1 pc/cc and is localised to a host galaxy at z = 0.522 (Macquart et al, 2020).

FRB200919 was detected at UTC 2020-09-19-14:41:35.83 in BEAM 03 centered at the coordinates RA = 22:07:29.7, Dec = -80:06:34.5. The detection Signal-to-Noise ratio (S/N) was 99.8 and the width was 0.9 ms. Using the radiometer equation, an early estimate of the lower limit on the burst fluence is 4.7 Jy ms. The S/N optimising DM is found to be 622 pc/cc. NE2001 model of the Milky Way electron density predicts a galactic DM contribution of 56 pc/cc along this line of sight to the FRB, leaving a excess of 566 pc/cc, which can be used to place a rough upper limit on the redshift of the host galaxy of ~0.57 if the FRB lies along an average line of sight through the Universe.

FRB200914 was detected at UTC 2020-09-14-14:28:47.27 in BEAM 12 which was centered at the coordinates RA = 21:46:38.3, Dec = -81:04:38.0. The detection S/N was 10.8 and the width was 1.9 ms. Using the radiometer equation, an early estimate of the lower limit on the burst fluence is 0.9 Jy ms. The S/N optimising DM is found to be 492 pc/cc. NE2001 model of the Milky Way electron density (Cordes and Lazio 2002, astro-ph/0207156) predicts a galactic DM contribution of 58 pc/cc along this line of sight to the FRB, leaving an excess of 434 pc/cc, which can be used to place a rough upper limit on the redshift of the host galaxy of z ~0.43 if the FRB lies along an average line of sight through the Universe.

The uncertainty in the localisation for both the sources is approximately 14.5 arcmin (FWHM of the Parkes beam). Both FRBs were detected in only one beam and their localisation regions do not overlap with the host galaxy of FRB190711, ruling out that any of these FRBs is a repeat burst from FRB190711. We encourage follow-up with other available facilities at different wavelengths and observing windows.

The dynamic spectra of the two bursts can be viewed at the following link: (https://tinyurl.com/y3t98hhl)