N(H₂) vs. CO(1–0) flux of the synthetic emission maps for the disk and dwarf galaxies. The blue and red points correspond to the pixels of the disk and dwarf galaxies respectively. The solid black line is the W_CO(1−0) = X_CO,MWN(H₂) curve, with the observed ±30% uncertainty band (Bolatto et al. 2013) shown by the black dashed lines. This uncertainty could be up to a factor of two under a variety of conditions. X_CO for pixels with W_CO(1−0) < 10K km s^-1 diverges from that of the Milky way, where the mean X_CO for the pixels is plotted in green. We note that 99% of the luminosity of the disk galaxy emanates from pixels whose W_CO(1−0)> 1K km s^-1 indicated by the dot-dashed line.