X-ray narrow line region variability as a geometry probe: The case of NGC 5548.

We present results on the geometry and location of the X-ray narrow line region in NGC 5548 obtained by analyzing multiple high-resolution X-ray grating observation covering an almost 10 year period. Variability combined with the high spectral resolution of the gratings aboard Chandra and XMM-Newton are key for obtaining these results. The goal is to extend this method to other type 1 AGN as well. [ABSTRACT FROM AUTHOR]