At UTC 2020-05-08-07:42:09.5 (2020-05-08.320943), we found a fast radio burst as part of the ongoing search program (UTMOST), at the Molonglo telescope.
Molonglo is a 1.6 km long East-West array (Bailes et al 2017, PASA, 34, 45) and was operating in drift-scan mode with pointing centred on 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).
FRB200508 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: 629 pc cm^-3. The DM estimate of NE2001 model is ~144.9 pc cm^-3, and YMW16 model is ~248.2 pc cm^-3 at this position, resulting in an intergalactic excess of ~433 pc cm^-3. The upper limit on the DM-inferred redshift is thus z ~ 0.39.
An early estimate (lower limit) of the event’s apparent fluence is ~29.7 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 = 14.33.
The most likely position is RA = 09:01:32.39, DEC =-65:35:42.7, J2000, Galactic: Gl = 282.02095755 deg, Gb = -12.5633715542 deg. The 95% confidence localisation arc is as follows: (RA, DEC) in (hours, deg).
9.083156 -69.939722
9.075233 -69.440667
9.067694 -68.941528
9.060517 -68.442306
9.053669 -67.943000
9.047136 -67.443611
9.040892 -66.944167
9.034922 -66.444667
9.029211 -65.945083
9.023739 -65.445472
9.018492 -64.945806
9.013458 -64.446083
9.008628 -63.946306
9.003986 -63.446500
8.999522 -62.946667
8.995228 -62.446778
8.991094 -61.946833
8.987114 -61.446889
A formula describing the localisation arc is:
RA = 9.026409 – 1.1189104e-2*(DEC + 65.69456) + 4.823077e-4*(DEC + 65.69456)**2
where RA is in hours, Dec is in deg, and is valid in the range Dec= [-61.5, -70]
Follow-up observations of the FRB are encouraged.