A Milliarcsecond Localization Associates FRB 20190417A with a Compact Persistent Radio Source and an Extreme Magnetoionic Environment
Journal article, 2026
We report the milliarcsecond localization of a high (similar to 1379 pc cm(-3)) dispersion measure (DM) repeating fast radio burst (FRB), FRB 20190417A. Combining European VLBI Network detections of five repeat bursts, we confirm the FRB's host to be a low-metallicity, star-forming dwarf galaxy at z = 0.12817, similar to the hosts of FRB 20121102A, FRB 20190520B, and FRB 20240114A. We also confirm that it is associated with a previously reported persistent radio source (PRS), which is compact on milliarcsecond scales. Visibility-domain model fitting constrains the transverse physical size of the PRS to <23 pc and yields an integrated flux density of 190 +/- 40 mu Jy at 1.4 GHz. Though we do not find significant evidence for DM evolution, FRB 20190417A exhibits a time-variable rotation measure (RM) ranging between +3958 +/- 11 rad m(-2) and +5061 +/- 24 rad m(-2) over a 50-day period. We find no evidence for intervening galaxy clusters in the FRB's line of sight and place a conservative lower limit on the rest-frame host DM contribution of 1228 pc cm(-3) (90% confidence)-the largest known for any FRB so far. This system strengthens the emerging picture of a rare subclass of repeating FRBs with large and variable RMs, above-average host DMs, and luminous PRS counterparts in metal-poor dwarf galaxies. Our results suggest that these systems are the result of environmental selection, or a distinct engine for FRB emission.
Author
Alexandra M. Moroianu
University of Amsterdam
Shivani Bhandari
Commonwealth Scientific and Industrial Research Organisation (CSIRO)
Maria R. Drout
University of Toronto
Jason W. T. Hessels
Netherlands Institute for Radio Astronomy (ASTRON)
University of Amsterdam
McGill University
Dante M. Hewitt
University of Amsterdam
Franz Kirsten
Chalmers, Space, Earth and Environment, Onsala Space Observatory
Benito Marcote
Netherlands Institute for Radio Astronomy (ASTRON)
Joint Institute for VLBI in Europe (JIVE)
Ziggy Pleunis
Netherlands Institute for Radio Astronomy (ASTRON)
University of Amsterdam
Mark P. Snelders
Netherlands Institute for Radio Astronomy (ASTRON)
University of Amsterdam
Navin Sridhar
Stanford University
Uwe Bach
Max Planck Society
Emmanuel K. Bempong-Manful
University of Bristol
University of Manchester
Vladislavs Bezrukovs
Ventspils University of Applied Sciences
Richard Blaauw
Netherlands Institute for Radio Astronomy (ASTRON)
Justin D. Bray
University of Manchester
Salvatore Buttaccio
Istituto nazionale di astrofisica (INAF)
Shami Chatterjee
Cornell University
Alessandro Corongiu
Istituto nazionale di astrofisica (INAF)
Roman Feiler
Nicolaus Copernicus University (SGMK)
B. M. Gaensler
University of Toronto
University of California
Marcin P. Gawronski
Nicolaus Copernicus University (SGMK)
Marcello Giroletti
Istituto nazionale di astrofisica (INAF)
Adaeze L. Ibik
University of Toronto
Ramesh Karuppusamy
Max Planck Society
Mattias Lazda
University of Toronto
Calvin Leung
University of California
Michael Lindqvist
Chalmers, Space, Earth and Environment, Onsala Space Observatory
Kiyoshi W. Masui
Massachusetts Institute of Technology (MIT)
Daniele Michilli
Aix Marseille University
Kenzie Nimmo
Massachusetts Institute of Technology (MIT)
Omar S. Ould-Boukattine
Netherlands Institute for Radio Astronomy (ASTRON)
University of Amsterdam
Ayush Pandhi
University of Toronto
Zsolt Paragi
Joint Institute for VLBI in Europe (JIVE)
Aaron B. Pearlman
McGill University
Weronika Puchalska
Nicolaus Copernicus University (SGMK)
Paul Scholz
University of Toronto
York University
Kaitlyn Shin
California Institute of Technology (Caltech)
Jurjen J. Sluman
Netherlands Institute for Radio Astronomy (ASTRON)
Matteo Trudu
Istituto nazionale di astrofisica (INAF)
David Williams-Baldwin
University of Manchester
Jun Yang
Chalmers, Space, Earth and Environment, Onsala Space Observatory
Astrophysical Journal Letters
2041-8205 (ISSN) 2041-8213 (eISSN)
Vol. 996 1 L16Onsala space observatory infrastructure
Swedish Research Council (VR) (2017-00648), 2018-01-01 -- 2021-12-31.
Subject Categories (SSIF 2025)
Astronomy, Astrophysics, and Cosmology
Meteorology and Atmospheric Sciences
DOI
10.3847/2041-8213/ae28c7