Maxwell response and eccentric tidal forcing spectrum. The rows show decreasing eccentricity, corresponding to tidal migration along a constant angular momentum track; columns show decreasing n_fτ_M, corresponding to heating and a shorter tidal relaxation time. Black curves show the Maxwell response ﹩{\rm{Im}}({k}_{2})﹩, and solid vertical black lines mark the Maxwell peak, ∣ω∣τ_M = 1. Colored vertical lines show the relative modal heating weights ﹩(| {\omega }_{mN}| /{n}_{{\rm{f}}}){{ \mathcal F }}_{mN}﹩ for m = 0, ±2, where ﹩{{ \mathcal F }}_{mN}=| {W}_{2m}{F}_{mN}{| }^{2}﹩. Frequencies are measured in the planetary rotating frame and normalized by the final circular mean motion n_f. Gray dotted lines and circles mark the dissipation-weighted effective forcing frequency ω_eff. At high eccentricity, the heating is produced by the overlap of many high-order harmonics with the viscoelastic response, rather than by a single forcing frequency.