2021RNAAS...5...65P

I have studied the variability of the FeKα emission line flux in response to changes in the 2-10 keV unabsorbed flux in a sample of Compton thin type-II active galactic nuclei. All of the 20 sources in the sample studied by Laha et al., exhibit the presence of a narrow FeKα emission line. Except for one source (NGC 2992), all other sources show no correlations between the FeKα emission line flux and 2-10 keV unabsorbed flux. This implies that although most of the sources have shown significant variations in their 2-10 keV flux, the FeKα emission line did not get enough time to respond to those changes. This helps us put lower limits on the distance of the FeKα emitters to >10 lt-yr from the central engine, equivalent to ∼3 pc which is consistent with the standard torus/narrow-line-region distance. I conclude that the FeKα emission lines of these sources arise from reflection of the hard X-ray photons off neutral materials located beyond pcscale.