RELATIVISTIC BEAMING EFFECTS AND STRUCTURAL ASYMMETRIES IN HIGHLY ASYMMETRIC DOUBLE RADIO SOURCES

Abstract

We have studied the comparative importance of the relativistic beaming model (RBM) and the density variation model (DVM) in our understanding of asymmetries in double radio sources, using their lobe separation ratio (Q) and flux density ratio (F). Our result shows an F − Q correlation in the sense expected for the RBM but contrary to the DVM. We attributed the result for the DVM to varying beam power, as its efficiency is density profile-dependent. From the coredominant parameter-linear size R − D relation for the RBM subsample, we found that sources in this subsample are beamed within an optimum cone angle Phi_c≈8°. We posit that relativistic beaming is largely accountable for the observed structural asymmetries in radio sources, though other effects cannot be ruled out.