Year: 2025
Type: article
Abstract: ABSTRACT We present the discovery and localization of a repeating fast radio burst (FRB) source from the MeerTRAP project, a commensal fast radio transient search programme using the MeerKAT telescope. FRB 20240619D was first discovered on 2024 June 19 with three bursts being detected within 2 min in the MeerKAT L band (856–1712 MHz). We conducted follow-up observations of FRB 20240619D with MeerKAT using the Ultra-High Frequency (UHF; $544\!-\!1088$ MHz), L-band and S-band (1968–2843 MHz) receivers one week after its discovery, and recorded a total of 249 bursts. The MeerKAT-detected bursts exhibit band-limited emission with an average fractional bandwidth of 0.31, 0.34, and 0.48 in the UHF, L-band, and S-band, respectively. We find our observations are complete down to a fluence limit of $\sim 1$ Jy ms, above which the cumulative burst rate follows a power law $R (>F)\propto (F/1\, \text{Jy}\, \text{ms})^\gamma$ with $\gamma =-1.6\pm 0.1$ and $-1.7\pm 0.1$ in the UHF and L band, respectively. The near-simultaneous L-band, UHF, and S-band observations reveal a frequency dependent burst rate with $3\times$ more bursts being detected in the L band than in the UHF and S band, suggesting a spectral turnover in the burst energy distribution of FRB 20240619D. Our polarimetric analysis demonstrates that most of the bursts have $\sim 100~{{\ \rm per\ cent}}$ linear polarization fractions and $\sim 10\!-\!20~{{\ \rm per\ cent}}$ circular polarization fractions. We find no optical counterpart of FRB 20240619D in the MeerLICHT optical observations simultaneous to the radio observations and set a fluence upper limit in MeerLICHT’s q band of 0.76 Jy ms and an optical-to-radio fluence ratio limit of 0.034 for a 15 s exposure.
Institutions: University of Manchester, University of Oxford, The University of Sydney, ARC Centre of Excellence for Gravitational Wave Discovery, University of Cape Town, University of South Africa, North-West University, Centre National de la Recherche Scientifique, Observatoire de Paris, Laboratoire de Physique et Chimie de l’Environnement et de l’Espace, Max Planck Institute for Radio Astronomy, Radboud University Nijmegen, South African Astronomical Observatory, University of Amsterdam
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $3,046
Funders: Australian Government, European Commission, National Research Foundation, Nederlandse Organisatie voor Wetenschappelijk Onderzoek, Max-Planck-Gesellschaft, Observatoire de Paris, Université de Recherche Paris Sciences et Lettres, Science and Technology Facilities Council, Australian Research Council, H2020 European Research Council
OpenAlex ID: W4410360284