M. Dovciak, G. Matt, et al.
Copious amounts of intervening gas are frequently present within AGN along our line of sight at larger distances from the black hole, resulting in additional spectral signatures superposed on the X-ray continuum and emission features.
Orbiting clouds and outflowing winds are likely present up to a few light days from the black hole, while at scales of 0.1–1 pc a low ionization, dusty torus-like structure is present. Primary X-rays are reprocessed in all of these regions, and strong absorption and emission features are produced.
The combination of the large effective area and fine energy resolution of Athena will enable the various spectral components to be de-convolved.