At UTC 2019-12-23-04:55:31.2 (2019-12-23.205222222), 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, 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).
FRB191223 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: 665 pc cm^-3. The DM estimate of NE2001 model is ~60.0 pc cm^-3, and YMW16 model is ~45 pc cm^-3 at this position, resulting in an intergalactic excess of ~605 pc cm^-3. The upper limit on the DM-inferred redshift is thus z ~ 0.55.
An early estimate (lower limit) of the event’s apparent fluence is ~108.1 Jyms (corrected for attenuation of the primary beam in the RA direction, but not in the Dec direction), with a detection signal-to-noise ratio = 29.4.
The most likely position is RA = 20:34:14.14, DEC = -75:08:54.19, J2000, Galactic: Gl = 318.854777 deg, Gb = -32.6614779 deg. The 95% confidence localisation arc is as follows: (RA, DEC) in (hours, deg)
20.498042 -77.518750
20.505189 -77.319778
20.512114 -77.120750
20.518828 -76.921667
20.525339 -76.722556
20.531658 -76.523417
20.537792 -76.324222
20.543747 -76.125028
20.549533 -75.925778
20.555156 -75.726472
20.560625 -75.527167
20.565942 -75.327833
20.571117 -75.128444
20.576153 -74.929056
20.581058 -74.729639
20.585833 -74.530194
20.590489 -74.330722
20.595025 -74.131222
20.599447 -73.931694
20.603761 -73.732167
20.607969 -73.532611
20.612075 -73.333028
20.616083 -73.133444
20.619994 -72.933806
20.623817 -72.734194
A formula describing the localisation arc is:
RA = 20.571174 + 2.61223e-2*(DEC + 75.127624) -1.79263e-3*(DEC + 75.127624)**2
where RA is in hours, DEC is in deg, and is valid in the range DEC = [-73, -77].
