Panels a) and b) ΔT_eff (ours minus GCSII) as a function of our T_eff (upper) and  [Fe/H]  (lower) for stars in the irfm sample. Panels c) and d) same as before, but for all remaining GCS stars in the clbr sample (see discussion in Sect. 2.1). Contour levels are computed on abscissa intervals of 25 K and 0.025 dex, respectively, to equally represent regions with fewer stars. Dashed and dotted lines indicate the mean difference and standard deviation of the entire sample; because they are symmetric and are dominated by regions with the highest overdensity of stars, the dashed and dotted lines are in some cases offset from the local 1σ contour levels.