Living on a Flare: Relativistic Reflection in V404 Cyg Observed by NuSTAR During its Summer 2015 Outburst

Understand

We present first results from a series of $NuSTAR$ observations of the black hole X-ray binary V404 Cyg obtained during its summer 2015 outburst, primarily focusing on observations during the height of this outburst activity.

• The $NuSTAR$ data show extreme variability in both the flux and spectral properties of the source.
• This is partly driven by strong and variable line-of-sight absorption, similar to previous outbursts.
• The latter stages of this observation are dominated by strong flares, reaching luminosities close to Eddington.