Contour plot of ﹩{\chi }^{2}﹩ for the spiral-arms model. Similar to Figures 2 and 3, the red contours correspond to the ⁵¹V/⁵¹Cr fit, the blue contours correspond to the ⁴⁹Ti/⁴⁹V fit, and the dashed purple lines correspond to the combined ﹩{\chi }^{2}﹩ calculation. Note the discrepancy between the two observations is somewhat larger, but still similar in size to the disk-like model.