Graph of b₁, selectively for N = 32 and N = 16, corresponding to FWHM = 320′ and FWHM = 640′, presenting an enlarged view of the concerned resolutions. The observational curve is presented in yellow, and the curves corresponding to the average of simulations are presented in gray. Error bands corresponding to (1σ : 4σ) are also drawn. The bottom two panels present the visualization of the scalar temperature field in order to facilitate an appreciation of the structure of the field.