Propagation Diagnostics of Supernova Remnant Environments around Young Repeating Fast Radio Bursts. I. Hydrodynamic Evolution of the Source-local Dispersion Measure
- 1Xiamen University of Technology
- 2Nanjing University
- 3Key Laboratory of Modern Astronomy and Astrophysics (Nanjing University)
Abstract
Repeating fast radio bursts may reside in young supernova remnant (SNR) environments whose evolving plasma contributes to the observed dispersion measure (DM). We use two-dimensional axisymmetric hydrodynamic simulations to study the interaction between a continuous anisotropic wind from a young neutron star and homologously expanding supernova ejecta. We follow the evolution to approximately 160 yr and calculate the source-local DM along different viewing directions, using a passive tracer to separate wind and nonwind contributions. In the fiducial model, the strongly polar-focused wind inflates a low-density cavity, while the swept-up shell remains broadly rounded and the DM shows moderate angular variation. The DM is dominated by ejecta and swept-up nonwind material. The solid-angle-averaged ambient-subtracted excess DM declines throughout the evolution, approximately following t age − 2 during the first several tens of years and becoming modestly steeper later. Variations in wind and ejecta parameters modify the normalization, early evolution, and viewing-angle dependence, but the angle-averaged DM declines in all models, while different bipolar wind profiles produce similar long-term evolution. For FRB 20190520B, the fiducial model reaches a decline rate comparable to the source-frame value inferred from observations at approximately 20 yr, when the mean excess DM is approximately 1.8 × 10 ² pc cm ⁻³ . Thus, such a young environment can retain a substantial electron column while producing a rapid secular decrease. Repeater diversity suggests that SNR-driven expansion may coexist with additional time-dependent plasma structures or ionization changes.
Versions
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BibTeX
@article{fang2026propagation,
title = {{Propagation Diagnostics of Supernova Remnant Environments around Young Repeating Fast Radio Bursts. I. Hydrodynamic Evolution of the Source-local Dispersion Measure}},
author = {Xiang-Er Fang and Zhen-Yin Zhao and Yi-Qing Lin and Hao-Tian Lan and Fa-Yin Wang},
journal = {The Astrophysical Journal},
year = {2026},
month = sep,
doi = {10.3847/1538-4357/aea3f0},
url = {https://iopscience.iop.org/article/10.3847/1538-4357/aea3f0},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Propagation Diagnostics of Supernova Remnant Environments around Young Repeating Fast Radio Bursts. I. Hydrodynamic Evolution of the Source-local Dispersion Measure
AU - Xiang-Er Fang
AU - Zhen-Yin Zhao
AU - Yi-Qing Lin
AU - Hao-Tian Lan
AU - Fa-Yin Wang
PY - 2026
DA - 2026/09/30
JO - The Astrophysical Journal
DO - 10.3847/1538-4357/aea3f0
UR - https://iopscience.iop.org/article/10.3847/1538-4357/aea3f0
AB - Repeating fast radio bursts may reside in young supernova remnant (SNR) environments whose evolving plasma contributes to the observed dispersion measure (DM). We use two-dimensional axisymmetric hydrodynamic simulations to study the interaction between a continuous anisotropic wind from a young neutron star and homologously expanding supernova ejecta. We follow the evolution to approximately 160 yr and calculate the source-local DM along different viewing directions, using a passive tracer to separate wind and nonwind contributions. In the fiducial model, the strongly polar-focused wind inflates a low-density cavity, while the swept-up shell remains broadly rounded and the DM shows moderate angular variation. The DM is dominated by ejecta and swept-up nonwind material. The solid-angle-averaged ambient-subtracted excess DM declines throughout the evolution, approximately following t age − 2 during the first several tens of years and becoming modestly steeper later. Variations in wind and ejecta parameters modify the normalization, early evolution, and viewing-angle dependence, but the angle-averaged DM declines in all models, while different bipolar wind profiles produce similar long-term evolution. For FRB 20190520B, the fiducial model reaches a decline rate comparable to the source-frame value inferred from observations at approximately 20 yr, when the mean excess DM is approximately 1.8 × 10 ² pc cm ⁻³ . Thus, such a young environment can retain a substantial electron column while producing a rapid secular decrease. Repeater diversity suggests that SNR-driven expansion may coexist with additional time-dependent plasma structures or ionization changes.
SN - 0004-637X
SN - 1538-4357
ER -