Average (over regions 10 arcsec wide in the inner 100 arcsec, 30 arcsec wide at larger distance) age, metallicity, [α/Fe], and M/L_V profiles along the bar minor axis of M 31 (black full lines) tracing the CB component of M 31 (see Fig. 3). The black dashed line in the M/L_V plot shows the average (over the same regions) of the M/L_V 20% values. The black dashed line in the age plot shows the 20% percentile of the distribution of values in the bins; the black dotted lines in the other plots show the 34 and 84 percentile of the distributions of values in the bins. The straight lines (red for the inner bulge, magenta for the outer bulge; see Fig. 3) show the fitted gradients (see Table 2). The blue lines show the composite stellar population model according to Eq. (6) and Table 4, the dotted red and green lines the assumed profiles for the CB and B/P components, respectively. The blue dashed lines show the age and M/L_V profiles obtained using the age values denoted with “20%” in Table 4. The vertical dashed line indicates 0.13r_bar.