Figure adopted from Harfst et al. (2010) in their Fig. 13, and compares the mass function slopes from the best-fitting models of N-body simulations of the Arches cluster to the observed values of this work and also from Stolte et al. (2005). The black filled symbols represent the models with a Salpeter IMF with different lower mass limits, while green open symbols correspond to a model with a flat IMF. The models deviate primarily at larger radii (r > 0.4 pc). The derived slope from a model starting with a Salpeter IMF at birth in the radius of 1 pc is α ~  − 3, which is in good agreement with our finding of α_Nishi ~  − 3.21 ± 0.30 in the outskirts of the Arches cluster.