A Steadily Declining Dispersion Measure for the Repeating Fast Radio Burst FRB 20220529A: Evidence for a Fast Radio Burst Engine Embedded in an Expanding Supernova Remnant
Journal article, 2026
We present the discovery and subsequent 3.2 yr monitoring campaign of the repeating fast radio burst (FRB) FRB 20220529A with CHIME/FRB. We observe a gradual decline in dispersion measure (DM) of -0.881 +/- 0.001 pc cm-3 yr-1 (-1.235 +/- 0.001 pc cm-3 yr-1 in the rest frame), implying a >= 3.5% +/- 0.2% decrease in the total electron column in the source environment, and we see scattering timescale variations over weeks to years. We observe a short-lived excursion in which the DM rises by similar to 1 pc cm-3, immediately preceding an increase in transient Faraday rotation measure (RM) of similar to 2000 rad m-2 previously reported for this source, before returning to its gradual decline in DM. During this DM/RM excursion, we identify a local line-of-sight magnetic field of 3.4 +/- 0.2 mG around FRB 20220529A, corresponding to one of the most strongly magnetized FRB environments. We measure a decrease in the linear polarization fraction of FRB 20220529A bursts with decreasing frequency that we attribute to depolarization from multipath propagation in the source environment. We also place a 5 sigma upper limit on the spectral luminosity of an associated persistent radio source of <= 5 & times; 1028 erg s-1 Hz-1 at 1.5 GHz. These observations are consistent with FRB 20220529A originating from a young (approximately years to centuries old) expanding supernova remnant, with short-lived DM and RM variability arising from interactions with the supernova remnant or with a binary companion.
Author
Ayush Pandhi
McGill University
University of Toronto
Kenzie Nimmo
Northwestern Univ, Ctr Interdisciplinary Explorat & Res Astron, 1800 Sherman Ave
Massachusetts Institute of Technology (MIT)
Shion Andrew
Massachusetts Institute of Technology (MIT)
Charanjot Brar
National Research Council Canada
Shami Chatterjee
Cornell University
Amanda M. Cook
McGill University
University of Amsterdam
Alice Curtin
McGill University
University of Amsterdam
B. M. Gaensler
University of California
University of Toronto
Marcin Gawronski
Nicolaus Copernicus University (SGMK)
Jason Hessels
Netherlands Institute for Radio Astronomy (ASTRON)
McGill University
University of Amsterdam
Victoria M. Kaspi
McGill University
Tel Aviv University
Afrokk Khan
McGill University
Franz Kirsten
Chalmers, Space, Earth and Environment, Onsala Space Observatory
Mattias Lazda
University of Toronto
Calvin Leung
Miller Inst Basic Res, Stanley Hall, Room 206B
University of California
Robert Main
McGill University
Kiyoshi W. Masui
Massachusetts Institute of Technology (MIT)
Ryan Mckinven
McGill University
Daniele Michilli
Aix Marseille University
Mason Ng
McGill University
Omar Ould-Boukattine
University of Amsterdam
Netherlands Institute for Radio Astronomy (ASTRON)
Aaron B. Pearlman
McGill University
Massachusetts Institute of Technology (MIT)
Ziggy Pleunis
University of Amsterdam
Netherlands Institute for Radio Astronomy (ASTRON)
Alexander W. Pollak
National Aeronautics and Space Administration (NASA)
E. T. Sachin Pradeep
McGill University
Weronika Puchalska
Nicolaus Copernicus University (SGMK)
Mawson W. Sammons
McGill University
Paul Scholz
York University
Vishwangi Shah
McGill University
Kaitlyn Shin
California Institute of Technology (Caltech)
Seth R. Siegel
McGill University
Perimeter Institute for Theoretical Physics
Kendrick Smith
Perimeter Institute for Theoretical Physics
Astrophysical Journal Letters
2041-8205 (ISSN) 2041-8213 (eISSN)
Vol. 1000 2 L53Subject Categories (SSIF 2025)
Astronomy, Astrophysics, and Cosmology
Meteorology and Atmospheric Sciences
DOI
10.3847/2041-8213/ae52f8