Further measures of [α/Fe], and [Mg/Fe]. Top panel: [α/Fe]–σ relation obtained by fitting the SDSS data over different wavelength ranges: 4000–4800 Å (blue), 4800–5400 Å (green), and 5400–6600 Å including the Hβ region (red). Bottom panel: [X/Fe]–σ relation using magnesium-enhanced models (orange). These models combine the MILES Vazdekis et al. (2015) and the Conroy & Dokkum (2012b) predictions (see details in the text). For reference, the filled purple circles in both panels represent the results from Fig. 1.