The extreme velocities of the Ultra-fast Outflow components in the Quasar PDS 456

I will present the spectral analysis of Chandra/HETGS and NuSTAR observations of the quasar PDS 456 from 2015, and XMM-Newton and NuSTAR archival data from 2013-2014, together with Chandra/HETGS data from 2003. These Chandra/HETGS data, never analyzed before, represent a great value for studying UFOs in the low and medium X-ray energy bands, at high energy resolution. We analyzed the three different epochs in a consistent way, looking for absorption features corresponding to highly ionized blueshifted absorption lines from H-like and He-like ions of iron and nickel, as well as of other elements (O, Ne, Si, and S) in the soft band. We confirm the presence of a persistent ultra-fast outflow (UFO) with a velocity of v_out = -0.24--0.29c, previously detected in several works. We also report the detection of an additional faster component of the UFO with a relativistic velocity of v_out = -0.48c. Such fast UFOs have already been found in some AGN at high redshift, but outflows with such a huge velocity have never been detected in AGN from the local Universe. We implemented photoionization modeling, using XSTAR analytic model warmabs, to characterize the physical properties of the different kinematic components of the ultra-fast outflow and of the partial covering absorber detected in PDS 456. These two relativistic components of the ultra-fast outflow observed in the three epochs analyzed here are powerful enough to impact the host galaxy of PDS 456 through AGN feedback.