Optical/X-ray correlations during the V404 Cyg June 2015 outburst

Understand

We present a multiwavelength analysis of the simultaneous optical and X-ray light curves of the microquasar V404 Cyg during the June 2015 outburst.

• We have performed a comprehensive analysis of all the INTEGRAL/IBIS, JEM-X, and OMC observations during the brightest epoch of the outburst, along with complementary NuSTAR, AAVSO, and VSNET data, to examine the timing relationship between the simultaneous optical and X-ray light curves, in order to understand the emission mechanisms and physical locations.
• We have identified all optical flares which have simultaneous X-ray observations, and performed cross-correlation analysis to estimate the time delays between the optical and soft and hard X-ray emission.
• We have also compared the evolution of the optical and X-ray emission with the hardness-ratios.