4.2 Iron Emission Lines

To fit the iron emission lines, we added four Gaussian components (zgauss ) at 6.4keV (FeK$\alpha$), 6.67keV (FeHe$\alpha$), 6.96keV (FeLy$\alpha$), and 7.05keV (FeK$\beta$) in the rest frame to the continuum model as follows: $\textsf{tbnew}~\times \textsf{highecut}~ \times (\textsf{diskbb}~+ \textsf{zpowerlw}~+ \sum_{i=1}^{4} \textsf{zgauss}~(i))$.

As seen in Figure 3, the data are consistent with three Gaussian lines at energies between 6keV and 7keV, namely the K$\alpha$ fluorescent iron line at 6.4keV, the He$\alpha$ iron line at 6.67keV, and the Fe Ly$\alpha$ iron line at 6.96 keV blended with K$\beta$ fluorescent iron lines at 7.05. To measure the Ly$\alpha$ line flux correctly, we set the K$\beta$ line flux to the theoretical iron K$\beta$/K$\alpha$ flux ratio of 0.135 (e.g. see Palmeri et al., 2003), then estimated the Ly$\alpha$ line in the presence of a possible K$\beta$ contribution, whose absolute width and relative energy were also tied to the Fe K$\alpha$. The lines that we associate with fluorescent iron and He-like iron emission are significantly detected with positive equivalent widths.