Binary pulsar B1259-63 spectrum evolution: detailed study

TL;DR

This study investigates how the radio spectrum of pulsar B1259-63 varies with orbital phase, proposing models involving free-free absorption and cyclotron resonance, and links this to the broader GPS pulsar phenomenon.

Contribution

It introduces a detailed analysis of spectrum evolution in B1259-63 and suggests environmental factors as key to understanding GPS pulsar spectra, bridging binary and solitary pulsar observations.

Findings

Spectrum shape depends on orbital phase.

Proposed models involve free-free absorption and cyclotron resonance.

Links GPS pulsars to environmental effects similar to B1259-63.

Abstract

We studied the radio spectrum of PSR B1259-63 in an unique binary with Be star LS 2883 and showed that the shape of the spectrum depends on the orbital phase. We proposed a qualitative model which explains this evolution. We considered two mechanisms that might influence the observed radio emission: free-free absorption and cyclotron resonance. Recently published results have revealed a new aspect in pulsar radio spectra. There were found objects with turnover at high frequencies in spectra, called gigahertz-peaked spectra (GPS) pulsars. Most of them adjoin such interesting environments as HII regions or compact pulsar wind nebulae (PWN). Thus, it is suggested that the turnover phenomenon is associated with the environment than being related intrinsically to the radio emission mechanism. Having noticed the apparent resemblance between the B1259-63 spectrum and the GPS, we suggest that the same mechanisms should be responsible for both cases. Therefore, the case of B1259-63 can be treated as a key factor to explain the GPS phenomenon observed for the solitary pulsars with interesting environments and also another types of spectra (e.g. with break).