Best-fit values of n as a function of τ_V for the fitted DES galaxies with DECam global (left panel) and local (right panel) griz photometry. Results for the different galaxies are shown in gray. A Gaussian Process Regression is shown in solid blue, with dashed blue lines defining a 68% credible interval. The mean relation found for similar simulated galaxies by Chevallard et al. (2013) is shown in dashed orange, with ±25% error margins shown in dotted orange.