Mass-to-light ratio as a function of galactocentric radius according to the BVIgi stellar surface density map (filled triangles, in black in the online version). This is computed by averaging the stellar mass map and the V-band surface brightness along ellipses corresponding to the tilted ring model. We then compute M_∗/L_V as the ratio between these two quantities in units of M_⊙/L_⊙. We show for comparison the same ratio relative to the BVI stellar surface density map (open triangles, in red in the online version). The error bars are the standard deviations relative to azimuthal averages and do not take into account uncertainties in the mass determination.