  Active galactic nuclei host an accretion disc with an X-ray producing corona
around a supermassive black hole. In bright sources, such as the Seyfert 1
galaxy Mrk 335, reflection of the coronal emission off the accretion disc has
been observed. Reflection produces spectral features such as an iron emission
line, which allow for properties of the inner accretion disc and the corona to
be constrained. We perform a multi-epoch spectral analysis of all XMM-Newton,
Suzaku, and NuSTAR observations of Mrk 335, and we optimize our fitting
procedure to unveil correlations between the Eddington ratio and the spectral
parameters. We find that the disc's ionization parameter correlates strongly
with the Eddington ratio: the inner disc is more strongly ionized at higher
flux. The slope of the correlation is less steep than previously predicted.
Furthermore, the cut-off of the power-law spectrum increases in energy with the
Eddington ratio, whereas the reflection fraction exhibits a decrease. We
interpret this behaviour as geometrical changes of the corona as a function of
the accretion rate. Below ~10% of the Eddington limit, the compact and
optically thick corona is located close to the inner disc, whereas at higher
accretion rates the corona is likely optically thin and extends vertically
further away from the disc surface. Furthermore, we find a soft excess that
consists of two components. In addition to a contribution from reflection in
low ionization states, a second component is present that traces the overall
flux.
