Desorption behaviour of N₂ in the different regimes, colour coded for the abundance of nitrogen in the ice with respect to water. Each column shows the different desorption events for N₂ with the integration limits for the desorption events given in Table 2. The data points indicated with a diamond are the H₂O:N₂ ices, with negligible amounts of CO₂ in the mixture. The colour assignment is the same as in Fig. 2. Top row: desorption behaviour of N₂ as a function of the total N₂ in the mixture, the total CO₂ abundance in the mixture, and the H₂O abundance respectively. The N₂ desorption occurring at the pure N₂ desorption peak and the CO₂ co-desorption have been fitted with a linear function and the resulting best fit is shown in the corresponding panel (grey, dashed line). The grey shaded region indicates the standard deviation of the fit. For the water co-desorption no overall fit has been done, however, trends for the different N₂ abundances have been indicated and colour coded. Bottom row: same data as in the top row, but plotted as a function of the total N₂ abundance in the ice mixture.