Relativistic Winds in Quasars

Some of the most fascinating properties of quasars arise from the
strong gravitational field that dominates over all other forces near
the supermassive black hole (SMBH). Observations of the X-ray spectra
of quasars have the potential of testing the theory of General
Relativity in a region of strong gravity, constraining the structure
of the X-ray emitting region, and further our understanding of the
quasars' role in feedback, quenching of star formation and galaxy
evolution.  I will present results from the detection of
near-relativistic winds launched near the innermost stable circular
orbits of SMBHs. A recent detection of a powerful wind in the X-ray
bright quasar HS 0810 strengthens the case that quasars play a
significant role in feedback.  The two main mechanisms proposed for
accelerating ultra-fast quasar outflows are radiation and magnetic
driving. I will briefly review these acceleration mechanisms and test
them against current observations of ultra-fast outflows.