A steadily declining dispersion measure for the repeating fast radio burst FRB 20220529A: Evidence for an FRB engine embedded in an expanding supernova remnant
Abstract
We present the discovery and subsequent 3.2 year monitoring campaign of the repeating fast radio burst FRB 20220529A with CHIME/FRB. We observe a gradual dispersion measure (DM) decline of −0.881±0.001 pc cm−3 year−1 (−1.235±0.001 pc cm−3 year−1 in the rest frame), implying a ≥3.5±0.2% decrease of 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 ∼ 1 pc cm−3, immediately preceding a transient ∼ 2000 rad m−2 Faraday rotation measure (RM) increase previously reported for this source, before returning to its gradual DM decline. We identify a local line-of-sight magnetic field around FRB 20220529A during this DM/RM excursion of 3.4 ± 0.2 mG, 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 multi-path propagation in the source environment. We also place a 5σ upper limit on the spectral luminosity of an associated persistent radio source of ≤ 5×1028 erg s−1 Hz−1 at 1.5 GHz. These observations are consistent with FRB 20220529A originating from a young (∼ 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.
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BibTeX
@article{pandhi2026steadily,
title = {{A steadily declining dispersion measure for the repeating fast radio burst FRB 20220529A: Evidence for an FRB engine embedded in an expanding supernova remnant}},
author = {Ayush Pandhi and Kenzie Nimmo and Shion Andrew and Charanjot Brar and Shami Chatterjee and Amanda M Cook and Alice Curtin and B.M Gaensler and Marcin Gawroński and Jason Hessels and Victoria M Kaspi and Afrokk Khan and Franz Kirsten and Mattias Lazda and Calvin Leung and Robert Main and Kiyoshi W Masui and Ryan Mckinven and Daniele Michilli and Mason Ng and Omar Ould-Boukattine and Aaron B Pearlman and Ziggy Pleunis and Alexander W Pollak and Sachin Pradeep E T. and Weronika Puchalska and Mawson W Sammons and Paul Scholz and Vishwangi Shah and Kaitlyn Shin and Seth R Siegel and Kendrick Smith},
journal = {Astrophys.J.Lett.},
year = {2026},
month = aug,
doi = {10.3847/2041-8213/ae52f8},
eprint = {2602.22309},
archivePrefix = {arXiv},
url = {https://hal.science/hal-05549638v1},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - A steadily declining dispersion measure for the repeating fast radio burst FRB 20220529A: Evidence for an FRB engine embedded in an expanding supernova remnant
AU - Ayush Pandhi
AU - Kenzie Nimmo
AU - Shion Andrew
AU - Charanjot Brar
AU - Shami Chatterjee
AU - Amanda M Cook
AU - Alice Curtin
AU - B.M Gaensler
AU - Marcin Gawroński
AU - Jason Hessels
AU - Victoria M Kaspi
AU - Afrokk Khan
AU - Franz Kirsten
AU - Mattias Lazda
AU - Calvin Leung
AU - Robert Main
AU - Kiyoshi W Masui
AU - Ryan Mckinven
AU - Daniele Michilli
AU - Mason Ng
AU - Omar Ould-Boukattine
AU - Aaron B Pearlman
AU - Ziggy Pleunis
AU - Alexander W Pollak
AU - Sachin Pradeep E T.
AU - Weronika Puchalska
AU - Mawson W Sammons
AU - Paul Scholz
AU - Vishwangi Shah
AU - Kaitlyn Shin
AU - Seth R Siegel
AU - Kendrick Smith
PY - 2026
DA - 2026/08/31
JO - Astrophys.J.Lett.
DO - 10.3847/2041-8213/ae52f8
UR - https://hal.science/hal-05549638v1
AB - We present the discovery and subsequent 3.2 year monitoring campaign of the repeating fast radio burst FRB 20220529A with CHIME/FRB. We observe a gradual dispersion measure (DM) decline of −0.881±0.001 pc cm^−3 year^−1 (−1.235±0.001 pc cm^−3 year^−1 in the rest frame), implying a ≥3.5±0.2% decrease of 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 ∼ 1 pc cm^−3, immediately preceding a transient ∼ 2000 rad m^−2 Faraday rotation measure (RM) increase previously reported for this source, before returning to its gradual DM decline. We identify a local line-of-sight magnetic field around FRB 20220529A during this DM/RM excursion of 3.4 ± 0.2 mG, 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 multi-path propagation in the source environment. We also place a 5σ upper limit on the spectral luminosity of an associated persistent radio source of ≤ 5×10^28 erg s^−1 Hz^−1 at 1.5 GHz. These observations are consistent with FRB 20220529A originating from a young (∼ 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.
ER -