Dynamics of energy supply to bright hot spots associated with 10 extragalactic radio sources

Abstract

For a representative sample of 10 bright hot spots associated with classical double radio sources and for the jets presumed to be feeding these hot spots, the authors have estimated some basic physical parameters, employing the beam model and making some reasonable assumptions about the geometry, spectra and energetics of the hot spots. Useful constraints are thus placed on the densities, bulk velocities, mass-flow rates and efficiencies of the jets. Continuing the same analysis, the authors have also estimated the bulk outflow velocities, Vout, of the relativistic electrons present inside the hot spots; it is found that Vout increases with the jet velocity and attains a maximum value of ≡0.25c for the case of an ultra-relativistic jet. In all the 10 hot spots the energy distribution of the relativistic electrons responsible for the radio output is estimated to cut off below a Lorentz factor of 250±50.