G. Matzeu

TL;DR: In this article, the authors present evidence for the rapid variability of the high-velocity iron K-shell absorption in the nearby quasar PDS 456, showing that the equivalent width of iron K absorption increases by a factor of ∼5 during the observation, increasing from <105 eV within the first 100 ks of the observation to a maximum depth of ∼500 eV near the end.

TL;DR: In this article, a spectral-variability analysis of the low-redshift quasar PDS 456 using principal component analysis is presented, showing that the absorption feature is more variable than the continuum, and that it is responding to the continuum.

TL;DR: A comparison of two Suzaku X-ray observations of the nearby (z = 0184), luminous (L bol ~ 1047 erg s−1) type I quasar, PDS 456, is presented in this article.

Abstract: 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 $v_{\rm w}/c \propto L_{7-30}^{\gamma}$ where $\gamma=0.22\pm0.04$. 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.