Testing accretion disk instabilities in X-ray binaries

Testing accretion disk instabilities in X-ray binaries

Patrycja Bagińska, Agata Różańska, Agnieszka Janiuk and Bożena Czerny

We study disk instabilities in black hole binaries in which X-ray novae outbursts were observed. Typically, one outburst occurs in each light curve, with total duration from 30 up to 400 days. The shape of an outburst can be very regular fast rise exponential decay (FRED) characteristic for ionisation instability mechanism that occurs in accretion disks, or irregular suggesting that, beside FRED, additional ickering occurs. We use the model which predicts time dependent evolution of ionisation instability in an accretion disk around black hole, assuming viscosity parameter to be proportional to the total pressure. We test it in detail for two objects: GX 339-4 and XTE J1818-245. The modelled light curves agree with the collected RXTE light curves, indicating that disk instability works in those objects.

Proceedings of the Polish Astronomical Society, vol. 1, 140-143 (2014)

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