Optimal L1L1 rate of decay to diffusion waves for the Hamer model of radiating gases

We are concerned with the asymptotic behavior of the solutions of a simplified model describing the evolution of a radiating gas. More precisely, we shall prove the convergence of HsHs solutions toward the classical diffusion wave of the viscous Burgers equation by means of entropy methods. The result is also endowed with the same L1L1 rate of convergence as that case.