Jeans models for the globular cluster NGC 1851 compared to the datapoints obtained in this work (black bullets) and the outer data points obtained by Scarpa et al. (2011, open squares). Panel a) shows the comparison of a model with and without fitting a M/L_V profile. The corresponding M/L_V profiles are shown in panel b). The panels c) and d) show various Jeans models with the varying M/L_V profile and with different black-hole masses and their χ² values. The best fit model is plotted as a black solid line and the blue shaded area in panel d) indicates the 1σ error on the black-hole mass.