Particle injection in the LSI+61º303 radio outbursts

Abstract

The binary radio, X-ray and gamma-ray star LSI+ 61 °303 presents periodic radio outbursts, of variable amplitude, with a period of 26.5 d. We propose a description of the radio outbursts using the adiabatic expansion model of a synchrotron emitting source, modified to incorporate a prolonged injection of energetic particles, and including the synchrotron and inverse Compton losses in the energy loss equation. We examine the two-frequency simultaneous radio observations of the 1981 August-September radio outburst. The agreement obtained between the observed and the calculated radio outburst is satisfactory and seems to indicate the important role played by particle injection in the LSI +61'303 radio outbursts.