The outburst of V404 Cygni in 2015

The outburst of V404 Cygni in 2015

Piotr Lubiński

Black hole binary systems are either permanent or transient X-ray sources. Transient sources are much more numerous and spend most of their time in a quiescent state. The outburst happens after some years or dozens of years and the object becomes one of the brightest X-ray sources in the sky. One of the most spectacular examples of transients is the microquasar V404 Cygni consisting of a black hole and a K-type star. Recent outburst of this object started on June 15th, 2015, after 31 years of quiescence. Contrary to the previous outburst, this time V404 Cygni was observed by dozens of satellites and on-ground facilities. This resulted in a substantial progress in our understanding of the physics of transient systems. In particular, the INTEGRAL satellite spent about a month observing the source in the X-ray and gamma-ray domains. A short review of the INTEGRAL results is presented here, with an emphasis on the broad band spectral study.

Proceedings of the Polish Astronomical Society, vol. 7, 304-309 (2018)

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