Radiation from a relativistic Poynting jet: some general considerations

We provide estimates for the flux and maximum frequency of radiation produced when the magnetic field in a relativistic, highlymagnetized, jet is dissipated and particles are accelerated using general considerations. We also provide limits on the jet Lorentz factor and magnetization parameter from the observed flux. Furthermore, using the Lorentz invariance of scalar quantities produced with electromagnetic tensor, we provide constraints on particle acceleration, and general features of the emergent radiation. We find that the spectrum below the peak softens with decreasing frequency. This spectral feature might be one way of identifying a magnetic jet.