V-band attenuation of the sample as a function of the stellar mass surface density. The black dot-dashed line is the best-fit line for our sample, and the gray shaded region is its corresponding 3σ uncertainty. The black open circles around some sources are the 3σ outliers of the –Σ_star relation, as shown in Fig. 6 and discussed in Sect. 4.1. The A_V values of our sample have a mean uncertainty of 0.12 mag.