Particle injection in the Circinus X-1 radio outbursts

A particle injection model has been applied to the radio outbursts of the X-ray binary Circinus X-1. The radio outbursts of this system have often been observed to exhibit a double peaked structure, i.e., with two apparent consecutive maxima. We show here that particle injection models can account for such observed behaviour provided that a time variable particle injection rate is adopted. Several possible time dependences are assumed and the corresponding predicted radio light curves compared with multi-frequency observations collected from the literature.