The high energy resolution view of warm absorbers

A number of absorption features are expected to be visible in high energy r esolution spectra of type 1 AGN with ionized gas along the line of sight (s o called "warm absorbers"). These include photoelectric absorption K and L edges along with many strong K alpha, K beta and L resonance absorption lin es from the most abundant elements. We present detailed simulations of our "photoelectric + resonant absorption" model with the high energy resolution gratings and calorimeters of AXAF, XMM and Constellation-X, and discuss th e relevant physics which can be addressed with the new generation of X-ray spectrometers.