Evidence for a radiatively driven disc-wind in PDS 456?

We present a newly discovered correlation between the wind outflow velocity and the X-ray luminosity in the luminous ($L_{\rm bol}\sim10^{47},\rm erg,s^{-1}$)nearby($z=0.184$) quasar PDS,456. All the contemporary XMM-Newton, NuSTAR and Suzaku observations from 2001–2014 were revisited and we find that the centroid energy of the blueshifted Fe,K absorption profile increases with luminosity. This translates into a correlation between the wind outflow velocity and the hard X-ray luminosity (between 7–30,keV) where we find that $v_{\mathrm{w}}\mathrm{/}c\propto L_{7-30}^{\gamma }$ where $\gamma =0.22\pm 0.04$. We also show that this is consistent with a wind that is predominately radiatively driven, possibly resulting from the high Eddington ratio of PDS,456.