Dataset and results for NGC 5457. The top row shows the 250 μm image, the molecular gas column density derived from CO observations for , the same for ; the central row shows the atomic gas column density N_H I, and the total column density N_H for the two choices of X_CO; the bottom rowI_ν(250 μm)/I_ν(500 μm), and ϵ_ν(250 μm) for the two X_CO. Maps of gas column densities have the same scale (top-right color bar), as well as the two ϵ_ν(250 μm) maps (bottom-right color bar). Contours on the ϵ_ν(250 μm) maps show the central value of the I_ν(250 μm)/I_ν(500 μm) bins used in the analysis. All images are convolved to FWHM ≈ 36″ (white circle in the top-left panel).