Mechanisms of the physical connection between the radio- and high-energy emissions of pulsars

TL;DR

This paper explores how radio photons in pulsars are converted into high-energy emissions through plasma interactions, explaining observed correlations in Crab and Vela pulsars and predicting stronger connections at lower radio frequencies.

Contribution

It introduces a new theoretical model detailing the physical mechanisms linking radio and high-energy emissions in pulsars, including resonant absorption and scattering processes.

Findings

Explains the radio-high-energy connection observed in Crab and Vela pulsars.

Predicts stronger radio-high-energy correlation at lower radio frequencies.

Suggests mechanisms for non-thermal high-energy emission in pulsars.

Abstract

The high-energy emission mechanisms based on the radio photon reprocessing by the ultrarelativistic plasma particles in the open field line tube of a pulsar are considered. The particles are believed to acquire relativistic gyration energies as a result of resonant absorption of pulsar radio emission. The spontaneous synchrotron re-emission of these particles falls into the optical and soft X-ray ranges and can at least partially account for the pulsar non-thermal high-energy emission. Besides that, the radio photons, which are still below the resonance, can be deposited into the high-energy range by means of the scattering off the gyrating particles. This process can also markedly contribute to the pulsar high-energy emission and underlie the potentially observable features of the radio -- high-energy connection. Based on the theory developed, we interpret the manifestations of the radio -- high-energy connection already observed in the Crab and Vela pulsars. Furthermore, it is shown that generally the most prominent connection is expected at the lowest radio frequencies, beyond the low-frequency turnover of a pulsar.