Disk Instability Model for Flares and Multiple Jet Ejections in a Black Hole Microquasar Candidate A0620-00

A time-dependent disk model is presented to account for possible multiple ejection events evidenced by the radio observations of A0620-00 during the early phase of the 1975 outburst. The model is based on the prescription of a time-dependent, irradiated, thermally unstable disk. The computed optical light curve and corresponding time-dependent behavior of the mass accretion rate in the disk are compared to the observed light curves in the radio, optical and X-rays. The model outburst consists of three flares: two precursor flares and a primary flare with maximum light, in which the peaks are enhanced according to the different local origins in the disk. In the second precursor and primary flares, the mass accretion rate of all the disk exceeds 10 percent of the Eddington value. Based on the result of the model, we show that the proposed multiple jet ejections seem to be related to multiple flares originating from a time-varying mass accretion rate in a thermally unstable disk.