The dust sublimation radius as an outer envelope to the bulk of the narrow Fe Kalpha line emission in Type 1 AGN

Understand

The Fe Kalpha emission line is the most ubiquitous feature in the X-ray spectra of active galactic nuclei (AGN), but the origin of its narrow core remains uncertain.

• Here, we investigate the connection between the sizes of the Fe core emission regions and the measured sizes of the dusty tori in 13 local Type 1 AGN.
• The observed Fe K emission radii (R_fe) are determined from spectrally resolved line widths in X-ray grating spectra, and the dust sublimation radii (R_dust) are measured either from optical/near-infrared reverberation time lags or from resolved near-infrared interferometric data.
• This direct comparison shows, on an object-by-object basis, that the dust sublimation radius forms an outer envelope to the bulk of the Fe K emission.