Massless Maxwell fields on sub-extremal Kerr-Newman exteriors

We study the massless Maxwell system on fixed sub–extremal Kerr-Newman exteriors. In the weak Kerr–Newman regimes with $0<\mathrm{\mid }a\mathrm{\mid }\le c_{a}M$, $0<\mathrm{\mid }Q\mathrm{\mid }\le c_{Q}M$, and $c_a,c_Q\in (0,1)$, we prove non–degenerate boundedness, Morawetz / integrated local energy decay, the outgoing $r^p$ hierarchy, radiation fields, polynomial decay, and two–sided scattering for the stationary-subtracted Maxwell field. In the axisymmetric relative slow–rotation regime $0<\mathrm{\mid }a\mathrm{\mid }\le {\epsilon }_{\mathrm{K}\mathrm{N}}\mathrm{\mid }Q\mathrm{\mid }<M$ with ${\epsilon }_{\mathrm{K}\mathrm{N}}\in (0,1)$, the same conclusions hold on the axisymmetric sector, with no perturbative restriction on $\mathrm{\mid }Q\mathrm{\mid }\mathrm{/}M$ beyond sub–extremality. For the full sub-extremal range $a^2+Q^2<M^2$, by adding one order–zero radiative local–energy estimate for this master system, we could obtain similar results as the weak regimes. This separates the unconditional weak theory from the conditional full–range theory within one reconstruction/scattering framework.