Constraining the FRB Central Engine from Flux Variations of Persistent Radio Sources: FRB 20240114A as the First Attempt
Year: 2026
Type: preprint
Abstract: Some repeating fast radio bursts (FRBs) are associated with persistent radio sources (PRSs), likely driven by the long-term activity of a central engine. We investigate FRB 20240114A-currently the most active repeating FRB-to explore the link between its burst activity and the flux variability of its associated PRS. We model electrons responsible for FRB emission being continuously injected from a central magnetar into its magnetar wind nebula (MWN), where synchrotron radiation produces the PRS. Comparing our model with the latest PRS spectra and flux variations, we constrain the physical properties of the FRB source. We find that the total energy injected into the MWN during FAST observations from January to August 2024 is $\sim 10^{48} \, \rm{erg}$, consistent with the magnetic energy budget of a magnetar with an internal magnetic field of $\sim 10^{16} \, \rm G$. The bulk Lorentz factor of the FRB-emitting plasma is mildly constrained to $\lesssim 10^3$, and FRB 20240114A is inferred to be powered by a young magnetar aged $\sim 10$-$20 \, \rm {yr}$. These results show that the PRS flux variability effectively probes FRB emission properties. We predict that while PRS luminosity increases rapidly with enhanced FRB activity, it will slowly fade over decades via adiabatic cooling after FRB activity ceases. Energetics suggest that the hyper-active phase observed in FRB 20240114A (burst rate $\sim 700 \, \rm hr^{-1}$) is a rare state with a duty cycle of $\lesssim 10^{-2}$, which is broadly consistent with its detection rate in current FRB-PRS samples.
Source: arXiv (Cornell University)
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Awards: G1364665103, G411936952, Study of the central engines of gamma ray bursts via measurement of GeV neutrinos, Gravitational collapse of ONeMg white dwarfs and associated transient high-energy phenomena, G730328427, Probing evolution of the universe by fast radio bursts and gamma-ray bursts, TAO望遠鏡と新技術可視光センサーで迫る中性子星の物理とバースト現象
OpenAlex ID: W7223117349