A Milliarcsecond Localization Associates FRB 20190417A with a Compact Persistent Radio Source and an Extreme Magnetoionic Environment
Abstract We report the milliarcsecond localization of a high (∼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 μ 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.
Authors
- B. Marcote (ORCID: https://orcid.org/0000-0001-9814-2354)
- Daniele Michilli (ORCID: https://orcid.org/0000-0002-2551-7554)
- D. M. Hewitt (ORCID: https://orcid.org/0000-0002-5794-2360)
- Kenzie Nimmo
- Ayush Pandhi (ORCID: https://orcid.org/0000-0002-8897-1973)
- Vladislavs Bezrukovs (ORCID: https://orcid.org/0000-0003-3655-2280)
- Calvin Leung (ORCID: https://orcid.org/0000-0002-4209-7408)
- Navin Sridhar (ORCID: https://orcid.org/0000-0002-5519-9550)
- Kaitlyn Shin (ORCID: https://orcid.org/0000-0002-6823-2073)
- W. Puchalska (ORCID: https://orcid.org/0000-0003-2422-6605)
- S. Buttaccio (ORCID: https://orcid.org/0000-0002-3341-466X)
- O. S. Ould-Boukattine (ORCID: https://orcid.org/0000-0001-9381-8466)
- A. Corongiu (ORCID: https://orcid.org/0000-0002-5924-3141)
- Justin D. Bray (ORCID: https://orcid.org/0000-0002-0963-0223)
- Alexandra Moroianu (ORCID: https://orcid.org/0000-0003-1936-9062)
- R. Feiler (ORCID: https://orcid.org/0000-0002-9812-2078)
- U. Bach (ORCID: https://orcid.org/0000-0002-7722-8412)
- M. Lindqvist (ORCID: https://orcid.org/0000-0002-3669-0715)
- Ziggy Pleunis (ORCID: https://orcid.org/0000-0002-4795-697X)
- Franz Kirsten (ORCID: https://orcid.org/0000-0001-6664-8668)
- Marcin Gawroński (ORCID: https://orcid.org/0000-0003-4056-4903)
- Emmanuel K. Bempong-Manful (ORCID: https://orcid.org/0000-0002-1727-1224)
- Z. Paragi (ORCID: https://orcid.org/0000-0002-5195-335X)
- Richard H. Blaauw
- Mattias Lazda (ORCID: https://orcid.org/0000-0002-5857-4264)
- Aaron B. Pearlman (ORCID: https://orcid.org/0000-0002-8912-0732)
- Jurjen J Sluman
- Shivani Bhandari (ORCID: https://orcid.org/0000-0003-3460-506X)
- Shami Chatterjee
- Marcello Giroletti
- Paul Scholz
- Jason W. T. Hessels
- David Williams-Baldwin
- B. M. Gaensler
- Matteo Trudu
- Adaeze L. Ibik
- Maria R. Drout
- Mark P. Snelders
- Kiyoshi W. Masui
- Jun Yang
Publication Details
- Journal
- The Astrophysical Journal Letters
- Published
- 2025-12-30
- DOI
- https://doi.org/10.3847/2041-8213/ae28c7
- Primary Topic
- Gamma-ray bursts and supernovae
- Type
- article
- Field-Weighted Citation Impact
- 0.00