Absolute values of χ² obtained from the fits of three data sets: all stars (top left panel), population I (bottom left), and population II (bottom right) for the observations along the major axis of the simulated galaxy. The results for the modeling of two populations (top right) were obtained as an algebraic sum of values for populations I and II. To avoid large numbers in the figure, Υ₀ was divided by the mean mass of a stellar particle.