X-Ray Absorption of AGN Outflows: Prospects for the future XRISM telescope

The physics behind the ionization structure of outflows from black holes is yet to be fully understood. Using archival observations with the Chandra/HETG gratings over the past two decades, we measured an absorption measure distribution for a sample of outflows in eight active galaxies (AGNs), namely the dependence of outflow column density, NH, on the ionization parameter, xi. The slope of log(NH) vs. log(xi) is found to be universally between 0.0 and 0.5. We find an anti-correlation between total column density of the outflow and the AGN luminosity, and none with the black hole mass and accretion efficiency. A major improvement in the diagnostics of AGN outflows will potentially occur with the launch of the XRISM/Resolve spectrometer. We study the ability of Resolve to reveal the outflow ionization structure by constructing the absorption measure distribution from simulated Resolve spectra, utilizing its superior resolution and effective area. Resolve constrains the column density of the high-xi components better than HETG, even with much shorter observations. These components carry the highest column densities