arXiv subjects

Mechiel Christiaan Bezuidenhout

Publications and source records attributed to Mechiel Christiaan Bezuidenhout.

7 recordsLinked to original sources

arXiv2026

A MeerKAT search for persistent radio sources towards twenty-five localised Fast Radio Bursts

The discovery of persistent radio sources (PRSs) associated with repeating fast radio bursts (FRBs) has shed light on the immediate environments and possible progenitors of these FRBs. The confirmed PRSs may support the theory that FRB progenitors are compact central engines, whilst the non-detections suggest diversity of FRB's local environment. We perform a subarcsecond-resolution MeerKAT search at 1.28 GHz on 25 well-localised FRB positions provided by ASKAP and MeerTRAP. We detect 14 radio sources and provide flux upper limits for 12 non-detections (both these numbers include a source that was detected during two epochs of observation, and not detected during one epoch, adding up to 26). One radio source shows variability as seen in flux variations over three epochs of observation. Archival optical data reveal excesses in the direction of 13 detected radio sources. Similarly for four sources in the X-ray band, with one possibly being a high-energy signature of a radio galaxy core. Since we cannot definitively classify our detected radio sources as PRSs, future high-resolution observations with e-MERLIN will be required to resolve the radio emission and pronounce on the presence of compact PRSs associated with the 14 detected sources presented here.

astro-ph.HE↗

arXiv2025

Search for persistent radio emission towards selected localised Fast Radio Burst positions using the MeerKAT Telescope

Fast Radio Bursts (FRBs) are millisecond-duration radio pulses originating from cosmological distances, as indicated by their large dispersion measures. While numerous FRBs have now been localised to their host galaxies, a distinct class of compact electromagnetic counterpart, a Persistent Radio Source (PRS), has also been identified in some cases. Currently, only three, and possible a fourth repeating FRBs (FRB20121102A, FRB20190417A, FRB20190520B, and FRB20240114A) have confirmed associations with a PRS. Insight into progenitors, local environments, and the evolution of FRBs can be clarified by characterising these PRSs. In this work, we present 2 detected candidate PRSs using MeerKAT radio telescope data and one non-detection (as part of a larger study involving 25 FRB positions). Both FRB20221106 and FRB20181112 were found to have a host galaxy, and whether the detected radio continuum emission comes from the host galaxy or PRS is still an open question. High-resolution observations from a telescope such as e-MERLIN are required to resolve this question. If a compact PRS is detected, this telescope will provide the size, and investigate the flux variability and spectral shape of this compact PRS. Lastly, in the case of FRB220190102, which was observed over two epochs, no radio continuum was detected. However, a flux upper limit is provided for both epochs.

astro-ph.HE↗

arXiv2025

A fast radio burst from the first 3 billion years of the Universe

Fast radio bursts (FRBs) are enigmatic millisecond-duration signals which encode otherwise unattainable information on the plasma which permeates our Universe, providing insights into magnetic fields and gas distributions. Here we report the discovery of FRB 20240304B originating at redshift 2.148 +/- 0.001 corresponding to just 3 billion years after the Big Bang. FRB 2024030 was detected with the MeerKAT radio telescope and localized to a low-mass, clumpy, star forming galaxy using the James Webb Space Telescope. This discovery doubles the redshift reach of localized FRBs and probes ionized baryons across ~80% of cosmic history. Its sightline, intersecting the Virgo Cluster and a foreground group, reveals magnetic field complexity over many gigaparsec scales. Our observations establish FRB activity during the peak of cosmic star formation and demonstrate that FRBs can probe galaxy formation during the most active era in cosmic time.

astro-ph.HE↗

arXiv2024

Timing analysis of rotating radio transients discovered with MeerKAT

Pulsars are rapidly rotating neutron stars that emit pulses of radiation at regular intervals, typically ranging from milliseconds to seconds. The precise recording and modelling of the arrival times of pulsar emission is known as timing analysis. Rotating radio transients (RRATs) are a subclass of pulsars that emit pulses very sporadically. Because of the sparse pulse times of arrival (ToAs) typically available for these sources, they are much more difficult to time than regular pulsars, to the extent that few RRATs currently have coherent timing solutions. In this work, we present the results of timing analyses for four RRATs discovered by the MeerTRAP transient survey using MeerKAT. We incorporated additional pulse ToAs from each source that have been detected since their original analysis. We confirmed the known timing solution for PSR J1843$-$0757, with a period of $P=2.03$ seconds, and a period derivative of $\dot{P}=4,13\times10^{-15}$. However, our analysis did not comport with the solution of MTP0005, which we conclude may have been mistakenly identified with the known PSR J1840$-$0815 in the original analysis. Finally, the spin period for MTP0007 was determined to be $1.023(1)$ seconds using a brute-force period fitting approach.

astro-ph.HE↗

arXiv2023

FRB 20210405I: a nearby Fast Radio Burst localised to sub-arcsecond precision with MeerKAT

We present the first sub-arcsecond localised Fast Radio Burst (FRB) detected using MeerKAT. FRB 20210405I was detected in the incoherent beam using the MeerTRAP pipeline on 2021 April 05 with a signal to noise ratio of 140.8 and a dispersion measure of 565.17 pc cm$^{-3}$. It was detected while MeerTRAP was observing commensally with the ThunderKAT large survey project, and was sufficiently bright that we could use the ThunderKAT 8s images to localise the FRB. Two different models of the dispersion measure in the Milky Way and halo suggest that the source is either right at the edge of the Galaxy, or outside. This highlights the uncertainty in the Milky Way dispersion measure models, particularly in the Galactic Plane, and the uncertainty of Milky Way halo models. Further investigation and modelling of these uncertainties will be facilitated by future detections and localisations of nearby FRBs. We use the combined localisation, dispersion measure, scattering, specific luminosity and chance coincidence probability information to find that the origin is most likely extra-galactic and identify the likely host galaxy of the FRB: 2MASS J1701249$-$4932475. Using SALT spectroscopy and archival observations of the field, we find that the host is a disk/spiral galaxy at a redshift of $z=0.066$.

astro-ph.HE↗

arXiv2022

Discovery of a radio emitting neutron star with an ultra-long spin period of 76 seconds

The radio-emitting neutron star population encompasses objects with spin periods ranging from milliseconds to tens of seconds. As they age and spin more slowly, their radio emission is expected to cease. We present the discovery of an ultra-long period radio-emitting neutron star, J0901-4046, with spin properties distinct from the known spin and magnetic-decay powered neutron stars. With a spin-period of 75.88 s, a characteristic age of 5.3 Myr, and a narrow pulse duty-cycle, it is uncertain how radio emission is generated and challenges our current understanding of how these systems evolve. The radio emission has unique spectro-temporal properties such as quasi-periodicity and partial nulling that provide important clues to the emission mechanism. Detecting similar sources is observationally challenging, which implies a larger undetected population. Our discovery establishes the existence of ultra-long period neutron stars, suggesting a possible connection to the evolution of highly magnetized neutron stars, ultra-long period magnetars, and fast radio bursts

astro-ph.HE↗

arXiv2021

MeerTRAP in the era of multi-messenger astrophysics

Real-time detections of transients and rapid multi-wavelength follow-up are at the core of modern multi-messenger astrophysics. MeerTRAP is one such instrument that has been deployed on the MeerKAT radio telescope in South Africa to search for fast radio transients in real-time. This, coupled with the ability to rapidly localize the transient in combination with optical co-pointing by the MeerLICHT telescope gives the instrument the edge in finding and identifying the nature of the transient on short timescales. The commensal nature of the project means that MeerTRAP will keep looking for transients even if the telescope is not being used specifically for that purpose. Here, we present a brief overview of the MeerTRAP project. We describe the overall design, specifications and the software stack required to implement such an undertaking. We conclude with some science highlights that have been enabled by this venture over the last 10 months of operation.

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