Panel a: count rate spectrum of Mrk 273 from NuSTAR plotted with the best-fit absorbed power-law model (Model (i) of Table 1 in histogram). The model includes a Gaussian line for the Fe K line at 6.4 keV. The data to model ratio is plotted in the bottom line. The best-fit slope is very hard (Γ = 1.26). Panel b: the same data plotted with the two source model, Model (iii). The best-fit models for the two absorbed continuum sources (labelled SW and N) and the total Fe K line (labelled Fe K) are drawn in light grey histograms.