Presentation #224.02 in the session “AGN and Quasars II”.
Evidence is growing that the interaction between outflows from active galactic nuclei (AGN) and their surrounding medium may play an important role in galaxy evolution, i.e. in the regulation of star formation in galaxies, through AGN feedback processes. Indeed, powerful outflows, such as the ultra-fast outflows (UFOs) that can reach mildly relativistic velocities of 0.2-0.4c, could blow away a galaxy’s reservoir of star-forming gas and hence quench the star formation in host galaxies. The low-redshift (z=0.184) radio-quiet quasar PDS 456 has shown the presence of a strong and blueshifted absorption trough in the Fe K band above 7 keV, which has been associated with the signature of such a fast and highly ionized accretion disk wind of a velocity of 0.25-0.3c. This persistent and variable feature has been detected in many observations of PDS 456, in particular by XMM-Newton, Suzaku and NuSTAR, together with other blueshifted absorption lines in the soft energy band. I will present the results of the analysis of contemporaneous high-resolution Chandra/HETGS and NuSTAR observations of PDS 456, and compare them with the previous findings, highlighting the detection of an even faster persistent UFO with a velocity of 0.48c.