Tachyonic Cherenkov radiation in the absorptive aether

•Tachyonic Maxwell–Proca radiation fields in a dispersive and dissipative spacetime.•Transversal/longitudinal Poynting flux vector & associated spectral energy density.•Energy dissipation quantified by absorption term in the energy conservation law.•Dissipative Cherenkov densities (classical) and tachyonic attenuation lengths.•Cherenkov energy flux from the shocked electron plasma of SNR RX J1713.7 − 3946.

Dissipative tachyonic Cherenkov densities are derived and tested by performing a spectral fit to the γ-ray flux of supernova remnant (SNR) RX J1713.7 − 3946, measured over five frequency decades up to 100 TeV. The manifestly covariant formalism of tachyonic Maxwell–Proca radiation fields is developed in the spacetime aether, starting with the complex Lagrangian coupled to dispersive and dissipative permeability tensors. The spectral energy and flux densities of the radiation field are extracted by time averaging, the energy conservation law is derived, and the energy dissipation caused by the complex frequency-dependent permeabilities of the aether is quantified. The tachyonic mass-square in the field equations gives rise to transversally/longitudinally propagating flux components, with differing attenuation lengths determined by the imaginary part of the transversal/longitudinal dispersion relation. The spectral fit is performed with the classical tachyonic Cherenkov flux radiated by the shell-shocked electron plasma of SNR RX J1713.7 − 3946, exhibiting subexponential spectral decay.