Mass outflow constraints in active nuclei and quasars from X-ray spectroscopy

Absorption in the X-ray spectra of active galactic nuclei from outflowing gas can be modeled to yield critical physical information on the outflows. The outflow rate of mass ejected back into the ISM of the host galaxy and the resulting feedback could potentially have an impact on evolution. We give a brief overview of the current observational constraints on the outflows that should be taken into account by models of evolution and feedback.