A HyperFlash and ÉCLAT view of the local environment and energetics of the repeating FRB 20240619D
Journal article, 2026
Time-variable propagation effects provide a window into the local plasma environments of repeating fast radio burst (FRB) sources. Here we report high-cadence observations of FRB 20240619D, as part of the HyperFlash and ÉCLAT programmes. We observed for 500h and detected 217 bursts, including 10 bursts with high fluence ($>25$Jy ms) and implied energy. We track burst-to-burst variations in dispersion measure (DM) and rotation measure (RM), from which we constrain the parallel magnetic field strength in the source’s local environment: $0.27\pm 0.13$mG. Apparent DM variations between sub-bursts in a single bright event are interpreted as coming from plasma lensing or variable emission height. We also identify two distinct scintillation screens along the line of sight, one associated with the Milky Way and the other likely located in the FRB’s host galaxy or local environment. Together, these (time-variable) propagation effects reveal that FRB 20240619D is embedded in a dense, turbulent and highly magnetised plasma. The source’s environment is more dynamic than that measured for many other (repeating) FRB sources, but less extreme compared to several repeaters that are associated with a compact, persistent radio source. FRB 20240619D’s cumulative burst fluence distribution shows a power-law break, with a flat tail at high energies. Along with previous studies, this emphasises a common feature in the burst energy distribution of hyperactive repeaters. Using the break in the burst fluence distribution, we estimate a source redshift of $z=0.042-0.240$. We discuss FRB 20240619D’s nature in the context of similar studies of other repeating FRBs.
radio continuum: transients
fast radio bursts
Author
O. S. Ould-Boukattine
Anton Pannekoek Institute for Astronomy
Netherlands Institute for Radio Astronomy (ASTRON)
A. J. Cooper
University of Oxford
J. W. T. Hessels
McGill University
Netherlands Institute for Radio Astronomy (ASTRON)
Anton Pannekoek Institute for Astronomy
Danté M. Hewitt
Anton Pannekoek Institute for Astronomy
S. K. Ocker
Carnegie Institution of Washington
California Institute of Technology (Caltech)
A. Moroianu
Anton Pannekoek Institute for Astronomy
K. Nimmo
Massachusetts Institute of Technology (MIT)
M. P. Snelders
Anton Pannekoek Institute for Astronomy
Netherlands Institute for Radio Astronomy (ASTRON)
I. Cognard
Station de Radioastronomie de Nançay
Laboratoire de Physique et de Chimie de l'Environnement et de l'Espace (LPC2E)
T. J. Dijkema
CAMRAS Dwingeloo Radio Telescope Foundation
Netherlands Institute for Radio Astronomy (ASTRON)
M. Fine
McGill University
Anton Pannekoek Institute for Astronomy
M. P. Gawroński
Nicolaus Copernicus University (SGMK)
W. Herrmann
Astropeiler Stockert e.V.
Jeff Huang
McGill University
Franz Kirsten
Netherlands Institute for Radio Astronomy (ASTRON)
Chalmers, Space, Earth and Environment, Onsala Space Observatory
Z. Pleunis
Anton Pannekoek Institute for Astronomy
Netherlands Institute for Radio Astronomy (ASTRON)
W. Puchalska
Nicolaus Copernicus University (SGMK)
S. Ranguin
Anton Pannekoek Institute for Astronomy
T. Telkamp
CAMRAS Dwingeloo Radio Telescope Foundation
Monthly Notices of the Royal Astronomical Society
00358711 (ISSN) 13652966 (eISSN)
Vol. 546 3 stag090Subject Categories (SSIF 2025)
Astronomy, Astrophysics, and Cosmology
DOI
10.1093/mnras/stag090