Extended Data Fig. 1: The effect of varying model parameters.
From: The diffuse γ-ray background is dominated by star-forming galaxies
The plots presented here show the result of our calculations when varying the model parameters as discussed in the Supplementary Information. Our fiducial choice is plotted as a solid blue line, with the dashed and dash-dotted lines showing the spectrum for the upper and lower limits respectively of the varied parameter. The black points correspond to the Fermi data as in Fig. 4. Plot a shows MA plotted for reasonable values of 1.6 and 2.3, and extremal values of 1.1 and 3.0; b the ionization fraction χ for values of 10−2 and 10−6; c the injection index q for values 2.1 and 2.3; and finally d the conversion fraction of supernova energy to CR electrons for values of 1% and 3%, which is equivalent to 10% and 30% of the total energy injected in all cosmic ray species. Note that varying the total CR energy budget results in a trivial scaling of the result by the same fraction, and thus is not shown
