A Compton-thick Wind in the High Luminosity Quasar, PDS 456
  PDS 456 is a nearby (z=0.184), luminous (L_bol ~10^47 erg/s) type I quasar. A
deep 190 ks Suzaku observation in February 2007 revealed the complex, broad
band X-ray spectrum of PDS 456. The Suzaku spectrum exhibits highly
statistically significant absorption features near 9 keV in the quasar
rest--frame. We show that the most plausible origin of the absorption is from
blue-shifted resonance (1s-2p) transitions of hydrogen-like iron (at 6.97 keV
in the rest frame). This indicates that a highly ionized outflow may be present
moving at near relativistic velocities (~0.25c). A possible hard X-ray excess
is detected above 15 keV with HXD (at 99.8% confidence), which may arise from
high column density gas (Nh>10^24cm^-2) partially covering the X-ray emission,
or through strong Compton reflection. Here we propose that the iron K-shell
absorption in PDS 456 is associated with a thick, possibly clumpy outflow,
covering about 20% of $4\pi$ steradian solid angle. The outflow is likely
launched from the inner accretion disk, within 15-100 gravitational radii of
the black hole. The kinetic power of the outflow may be similar to the
bolometric luminosity of PDS 456. Such a powerful wind could have a significant
effect on the co-evolution of the host galaxy and its supermassive black hole,
through feedback.
