eROSITA cosmology contours for biased mass function for Ω_M versus σ₈. The cross shows the input (true) cosmology value. The black contours give the sum of the offset significance between the biased and fit mass function. The contours were obtained by interpolating the offset significance values calculated for the grid of cosmological parameters (see grey diamonds). The red contours show the 1 and 3σ confidence level. The plot shows more coarse and finer contour levels around the best-fit values.