Observed galaxy luminosity functions (blue data points) in the J- (top) and Ks-band (bottom) for XDCP J0044.0-2033 extracted within a cluster-centric radius of 30′′ (≃250 kpc). The red lines show the best fit Schechter functions for three (φ*, m*, α) free parameters (dotted), two free parameters with a fixed faint end slope of α = − 1 (solid), and a single parameter normalization fit (dashed) using a SSP model magnitude for m* (green dashed vertical line). The dark blue vertical line with the grey shaded area indicates the best fit solution of the characteristic magnitude m* of the two parameter fit with 1σ uncertainties. The vertical black (dashed) solid lines on the right indicate the 100% (50%) completeness limits.