2025ApJ...988..276R -
Astrophys. J., 988, 276 (2025/August-1)
Persistent Radio Sources Associated with Fast Radio Bursts: Implications from Magnetar Progenitors.
RAHAMAN S.M., ACHARYA S.K., BENIAMINI P. and GRANOT J.
Abstract (from CDS):
The rare association of three persistent radio sources (confirmed PRS1 and PRS2, candidate PRS3) with repeating fast radio bursts (FRB 20121102A, 20190520B, 20201124A) offers a unique probe into their magneto-ionic environments. PRSs are attributed to synchrotron emission from relativistic charged particles of a magnetar wind nebula (MWN), powered by spin-down magnetohydrodynamic wind or internal magnetic field decay. Using a multizone hydrodynamic model, we track MWN evolution to constrain magnetar progenitor properties. For PRS1 and PRS2, we find an equipartition radius Req ∼ 0.1 pc that is consistent with the radio scintillation estimates (>0.03 pc) and radio imaging limits (<0.7 pc). This compact size favors low expansion speeds and large initial spin periods, Pi ≳ 10 ms, ruling out millisecond magnetar progenitors. Given Pi ≳ 10 ms, a current size of ∼0.1 pc, a supernova kinetic energy ${E}_{\mathrm{SN}}\sim 1{0}^{50}\mbox{--}1{0}^{51}$ erg, and an ejecta mass M ∼ 3-10 M⊙, the PRS age is t ∼ 10-102 yr. PRSs with t > 20 yr require an internal field (Bint ∼ 1016-1016.5 G) with a decay timescale td ∼ 10-102.5 yr. The slowest field decay (${t}_{{\rm{d}},{\rm{\max }}}\sim 500$ yr) favors subenergetic supernovae (${E}_{{\rm{SN}}}\sim 1{0}^{50}\ $ erg) with massive ejecta (M ≳ 10 M⊙) and a low-ionization fraction (∼3%). For the subenergetic scenario, for the confirmed PRSs, we predict a cooling break at 100-150 GHz at 20-40 μJy and self-absorption near 200 MHz at 180 μJy. For PRS3, a rotation-powered MWN is viable only if t ∼ 10 yr; an inverted spectrum beyond 150 GHz would rule out this scenario.
Abstract Copyright:
© 2025. The Author(s). Published by the American Astronomical Society.
Journal keyword(s):
Radio transient sources - Radio bursts - Radio continuum emission - Neutron stars
Simbad objects:
7
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