The XMM-Newton EPIC spectra of quasar J0439+1634. The upper panel shows the observed counts from the pn camera (black), MOS1 (red), and MOS2 (blue). The solid lines represent the spectral fits using an absorbed power-law model consistent of a power-law model, Galactic absorption, and quasar intrinsic absorption, with the assumption of an intrinsic photon index of Γ = 1.9 (Nanni et al. 2017). The dashed lines denote the spectral fits with a free Γ (see details of spectral fitting in Section 3.2). The bottom panel shows the residuals, with filled circles for the fixed-Γ fits and open squares for the Γ-free fits. The spectral fitting is applied to the spectra grouped to one count per bin, and the data have been rebinned for plotting purpose here using XSPEC.