Upper panel: Selene stellar disc age profile. Middle panel: Selene stellar disc metallicity profile. Bottom panel: Selene total velocity dispersion profile (disc stars). Red (blue) vertical dashed lines are located at the surface brightness break (minimum age) radius. The errorbars indicate the standard deviation of the values of every particle within each radial bin. h_in is the inner disc scale length in SDSS r-band mock images from SUNRISE (Jonsson 2006). These mock images can be seen in Few et al. (2012). Vertical arrows are located at the beginning and the end of the four regions defined in Table 2. Blue, region 1; green, region 2; red, region 3; black, region 4.