Six normalized quantities (see legend) as a function of time, where t/t′ = 90 Myr or about 1/3 of a dynamical time of the potential. To limit the total mass so that it does not become too large compared to the observations, the accretion ended at t′ = 6 (about 540 Myr or two dynamical times). The top panel is for a relatively high assumed efficiency of coupling of the mechanical energy output of the stellar population to the ISM (12%), whereas the bottom panel is for a relatively low coupling efficiency (5%). The scalings for these normalized quantities are provided in the text (see Elmegreen & Burkert 2010).