A χ² scan of PO models in the plane of masses HR 8799e and HR 8799c (left panels) and HR 8799d and HR 8799b (right panels) for the data set with (top row; ﹩{ \mathcal D }﹩) and without (bottom row; ﹩{{ \mathcal D }}_{1}﹩) the GPI measurements. The red filled symbols and circles/ellipses reference astrophysical masses ﹩{m}_{{\rm{e}}}=(7.2\pm 0.7){m}_{\mathrm{Jup}}﹩ and ﹩{m}_{{\rm{c}}}=(7.2\pm 0.7){m}_{\mathrm{Jup}}﹩ (left panels) and ﹩{m}_{{\rm{d}}}=(7.2\pm 0.7){m}_{\mathrm{Jup}}﹩ and ﹩{m}_{{\rm{b}}}=(5.8\pm 0.5){m}_{\mathrm{Jup}}﹩ (right panels) following Wang et al. (2018). The green filled point denotes the position of the minimum of χ² function, while the green contour denotes the level of ﹩\min {\chi }^{2}+1﹩. The white and black curves denote the levels of ﹩\min {\chi }^{2}+2,\,...,\,+6﹩, apart from the bottom left panel, in which the white contours denote the confidence levels of ﹩\min {\chi }^{2}+0.1,+0.3,+0.5﹩.