residuals plotted against effective temperature T_eff (rv_template_teff; see footnote 7) for stars with grvs_mag ≤ 12 mag. The black line shows the median relation. For stars cooler than T_eff ∼ 3500 K, grvs_mag is fainter than . This is because of the positive gradient produced by TiO absorption in the spectra of such stars, as shown by the inset spectrum of a star with grvs_mag = 10.3 and T_eff = 3300 K.