The mutual relationship between β and . Left panel: − β relation of our models (left panel) evolved without galactic winds. All the relationships are nearly identical passing from models with large radii to those with smaller radii (by a factor of 4), and the corresponding solutions of the equations for β and , and finally changing only the photometric passband in use. The relationships seem to depend only on the galaxy mass. Right panel: − β relation for the artificial galaxies of Illustris-1. Each color corresponds to a different redshift epoch: green (z = 4), blue (z = 3), yellow (z = 2.2), brown (z = 1.6), magenta (z = 1.0), dark gray (z = 0.6), red (z = 0.2), and light gray (z = 0).