Top: SFR surface density vs. total gas surface density (left) and vs. H₂ (right) for the MW disk, in the region between 2 and 13 kpc. In both panels, curves represent the same quantities as in Fig. B.1; the long dashed curve (SFR ∝ Σ(H₂)) corresponds quantitatively to the fit of Bigiel et al. (2008) to extragalactic data and fits the adopted “observed” SFR profile in the MW disk quite well. Bottom: the “observed” SFR vs. gas relation in the MW is compared to a compilation of extragalactic data from Krumholz et al. (2012).