Jet brightness asymmetry
= Jet brightness asymmetry
An approaching <jet> can be enhanced and its receding counterpart suppressed by different <Doppler factors>. A discrete moving emitter with rest-frame power-law spectrum $F_\nu\propto\nu^{-s}$ has the usual boost $\delta_D^{3+s}$, whereas a steady continuous-jet convention changes the exponent. Absorption and environmental asymmetry can also affect the contrast.