Sérsic index at rest-frame 1.5 μm (left panel) and rest-frame 0.5 μm (right panel) as a function of stellar mass. Dots in the background represent n_λ of the individual star-forming (blue) and quiescent (red) galaxies. Filled circles show the median n_λ in stellar mass bins of width 0.25 dex and four redshift bins from low-z (light) to high-z (dark). Error bars identify the statistical uncertainties computed as $\sigma /\sqrt{N}$ with N the number of galaxies within the bin and σ the standard deviation of the distribution. Solid lines show spline-quantile regression obtained using the COBS library (Ng & Maechler 2007, 2022). 16-50-84 percentiles of n at each redshift and mass bins are reported in Appendix B. The median uncertainty on the Sérsic index is shown in the bottom right corner as a black error bar. We report the number of galaxies in each redshift bin in the top right corner of each panel. In any redshift bin massive galaxies have higher n_λ than at lower mass.