Abstract
We report on the discovery and localization of fast radio bursts (FRBs) from the MeerTRAP project, a commensal fast radio
transient-detection programme at MeerKAT in South Africa. Our hybrid approach combines a coherent search with an average
field-of-view of 0.4 deg2 with an incoherent search utilizing a field-of-view of 1.27 deg2 (both at 1284 MHz). Here, we
present results on the first three FRBs: FRB 20200413A (DM=1990.05 pc cm3), FRB 20200915A (DM=740.65 pc cm3),
and FRB 20201123A (DM=433.55 pc cm3). FRB 20200413A was discovered only in the incoherent beam. FRB 20200915A
(also discovered only in the incoherent beam) shows speckled emission in the dynamic spectrum which cannot be explained by
interstellar scintillation in our Galaxy or plasma lensing, and might be intrinsic to the source. FRB 20201123A shows a faint
post-cursor burst about 200 ms after the main burst and warrants further follow-up to confirm whether it is a repeating FRB.
FRB 20201123A also exhibits significant temporal broadening consistent with scattering by a turbulent medium. The broadening
exceeds that predicted for medium along the sightline through our Galaxy.We associate this scattering with the turbulent medium
in the environment of the FRB in the host galaxy. Within the approximately 10 localization region of FRB 20201123A , we
identify one luminous galaxy (A 15•67; J173438.35504550.4) that dominates the posterior probability for a host association.
The galaxy’s measured properties are consistent with other FRB hosts with secure associations.
transient-detection programme at MeerKAT in South Africa. Our hybrid approach combines a coherent search with an average
field-of-view of 0.4 deg2 with an incoherent search utilizing a field-of-view of 1.27 deg2 (both at 1284 MHz). Here, we
present results on the first three FRBs: FRB 20200413A (DM=1990.05 pc cm3), FRB 20200915A (DM=740.65 pc cm3),
and FRB 20201123A (DM=433.55 pc cm3). FRB 20200413A was discovered only in the incoherent beam. FRB 20200915A
(also discovered only in the incoherent beam) shows speckled emission in the dynamic spectrum which cannot be explained by
interstellar scintillation in our Galaxy or plasma lensing, and might be intrinsic to the source. FRB 20201123A shows a faint
post-cursor burst about 200 ms after the main burst and warrants further follow-up to confirm whether it is a repeating FRB.
FRB 20201123A also exhibits significant temporal broadening consistent with scattering by a turbulent medium. The broadening
exceeds that predicted for medium along the sightline through our Galaxy.We associate this scattering with the turbulent medium
in the environment of the FRB in the host galaxy. Within the approximately 10 localization region of FRB 20201123A , we
identify one luminous galaxy (A 15•67; J173438.35504550.4) that dominates the posterior probability for a host association.
The galaxy’s measured properties are consistent with other FRB hosts with secure associations.
| Original language | English |
|---|---|
| Journal | Monthly Notices of the Royal Astronomical Society |
| Publication status | Accepted/In press - 20 May 2022 |