Ionization Distributions in Outflows of Active Galaxies: Universal Trends and Prospect of Future XRISM Observations

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, 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,𝜉. The slope of log𝑁𝐻vs. log𝜉is found to be universally between 0.0 and 0.5. We find an anti-correlation between the total column density of the outflow and the AGN luminosity. A major improvement in the diagnostics of AGN outflows will potentially occur with the launch of the XRISM/Resolve spectrometer.

In this work, we study the abilities of Resolve reveal the outflow ionization structure. We construct the absorption measure distributions using simulated Resolve spectra, utilizing its superior resolution and effective area. Resolve constrains the column density of the high-𝜉components better than HETG, even with much shorter observations. These components carry the highest column densities.