Probing the Extent of Fe Kα Emission in Nearby Active Galactic Nuclei Using Multi-order Analysis of Chandra High Energy Transmission Grating Data

We present a study of the narrow Fe K$\alpha$ line in seven bright, nearby AGN that have been observed extensively with Chandra High Energy Transmission Grating (HETG). The HETG data reveal wider first order spectrum than second and third spectra, which we interpret as result spatially extended emission. utilize these differences widths multi-order spectra to determine spatial extent intrinsic velocity width emitting material each object. find there is modest evidence for emission object, corresponding extension $r\sim5-100$ pc. These distances are significantly larger those inferred from assuming gravitational motions, give $r\sim0.01-1$ This implies either gas at range radii, smaller radii dominating extent, or exhibiting non-gravitational suggest would be outflows due slight excess redshift velocities exceed freefall velocity. also use information estimate mass by counting fluorescing iron atoms, finding masses on $M_\mathrm{gas}\sim10^5-10^8\,M_\odot$. Future work observatories like XRISM will able extend this number decrease uncertainties arise low signal-to-noise higher data.