NuSTAR view of Swift/BAT AGN: The $R$-$\Gamma$ correlation
  The reflection hump is a prominent feature in the hard X-ray spectrum of
active galactic nuclei (AGN). Its exact shape and its correlation to other
quantities provide valuable information about the inner and outer regions of an
AGN. Our main goal is to study the reflection hump in a large sample of nearby
AGN. We aim to investigate the evolution of reflection with absorption and its
correlation with the spectral index. We analysed archived NuSTAR observations
of the 70-month BAT catalogue AGN. By performing a detailed spectral analysis,
we were able to constrain the spectral parameters and to investigate the
reflection emission in a large sample of individual sources. The reflection
strength was found to be strongly correlated with the power-law slope in
unabsorbed sources, pointing towards disc reflection for these sources.
Different possible explanations were tested and the most likely one is that the
corona is moving either towards or away from the disc with a moderately
relativistic velocity. An $R-\Gamma$ correlation was not detected for absorbed
sources. In addition, these AGN feature harder spectra, suggesting intrinsic
differences between the two classes or a slab geometry for the X-ray source.
