2024/12/26 by Bhattacharya, Mukul, Murase, Kohta, Kashiyama, Kazumi
#FOS: Physical sciences #High Energy Astrophysical Phenomena (astro-ph.HE)
paper · doi:10.48550/arxiv.2412.19358
Among over 1000 known fast radio bursts (FRBs), only three sources - FRB 121102 (R1), FRB 190520 (R2) and FRB 201124 (R3) - have been linked to persistent radio sources (PRS). The observed quasi-steady emission is consistent with synchrotron radiation from a composite of magnetar wind nebula (MWN) and supernova (SN) ejecta. We compute the synchrotron flux by solving kinetic equations for energized electrons, considering electromagnetic cascades of electron-positron pairs interacting with nebular photons. For rotation-powered model, a young neutron star (NS) with age t\rm age≈ 20 \rm yr, dipolar magnetic field B\rm dip≈ (3-5)×1012 \rm G and spin period Pi≈ 1.5-3 \rm ms in an ultra-stripped SN progenitor can account for emissions from R1 and R2. In contrast, R3 requires t\rm age≈ 10 \rm yr, B\rm dip≈ 5.5×1013 \rm G and Pi≈ 10 \rm ms in a conventional core-collapse SN progenitor. For magnetar-flare-powered model, NS aged t\rm age ≈ 25 /40 \rm yr in a USSN progenitor and t\rm age ≈ 12.5 \rm yr in a CCSN progenitor explains the observed flux for R1/R2 and R3, respectively. Finally, we constrain the minimum NS age t\rm age,min ∼ 1-3 \rm yr from the near-source plasma contribution to observed DM, and t\rm age,min ∼ 6.5-10 \rm yr based on the absence of radio signal attenuation.