FRB180528 – UTMOST’s 6th FRB

 

On 2018-05-28-04:24:00.9 UTC (2018-05-28.18334375), UTMOST found a new FRB (FRB180528) as part of the ongoing search program at the Molonglo Radio Telescope (see Bailes et al. 2017, arxiv.org/abs/1708.09619). This is the sixth Molonglo FRB overall (See Atel #10867, ATel #10697 and Caleb et al. 2017, MNRAS, 468, 3746). The FRB was discovered in real time, and voltage capture was successfully triggered (see Farah et al 2018, https://arxiv.org/abs/1803.05697).

The dispersion measure (DM) of the FRB is: 899 pc cm^-3, which is substantially in excess of the Galactic DM as estimated by the NE2001 (www.nrl.navy.mil/rsd/RORF/ne2001/) model (~69 pc cm^-3). The upper limit on the DM-inferred redshift z is thus z~0.7. The S/N in the detection beam is 14, and a preliminary estimate of the event’s fluence is ~ 18 +/- 4 Jyms. This is a lower limit as the event’s position is poorly constrained in the North-South direction within the primary beam. The FRB’s estimated width (full width half power) is 1.3 ms.

Source localisation is excellent in the Right Ascension (~ 5 arcsec at 1-sigma) but poor in Declination (~1.2 deg at 1-sigma). The most likely position is RA = 06:38:48.7, DEC = -49:53:59, J2000, Galactic: Gl = 258.87 deg, Gb = -22.35 deg. The 95% confidence localisation arc is as follows: (RA, DEC) in (hours,deg)

6.642039 -53.065500
6.642700 -52.664778
6.643347 -52.264056
6.643978 -51.863306
6.644594 -51.462583
6.645197 -51.061833
6.645786 -50.661083
6.646361 -50.260361
6.646925 -49.859611
6.647475 -49.458861
6.648014 -49.058139
6.648542 -48.657389
6.649056 -48.256639
6.649561 -47.855889
6.650056 -47.455139
6.650539 -47.054389
6.651011 -46.653667

A formula describing the localisation arc is:

RA = 6.39652461344 – 0.00642068726059*(DEC – 49.8996671717) – 3.9200674396e-05*(DEC -49.8996671717)**2

Where RA is in hours, DEC is in deg, and is valid in the DEC range [-54,-46].

2018-05-30

Waterfall plot for FRB180528.

FRB20180528_localisation_860559

Localisation plot for FRB180528, with the center of the localisation arc marked by the green square. The telescope boresight position is marked by the blue square. The positions of 3 pulsars are also marked.