(B − V)_T distributions towards the Galactic north pole showing the effect of changing the age–velocity dispersion relation (AVR) against the default model B. Tycho-2 data (dashed green line) and the simulations based on the default model B (solid blue line) are shown. The dotted red line is based on simulations using an AVR of Holmberg et al. (2009) rather than of Gómez et al. (1997) but leaving all other parameters unchanged.