A study of the properties of twin radio arms of FR-II extragalactic radio sources within z ≤ 1

We carried out a comparative analysis on the properties the two arms (the longer arm and the shorter arm) on a sample of 98 FR-II radio galaxies comprising of 15 quasars, 11 broad-line radio galaxies, 57 narrow line radio galaxies and 15 low excitation radio galaxies within z <= 1. Our result indicates that in general, the arm lengths (lobe linear sizes) and luminosity, jets (lengths and luminosities), hotspots (sizes and luminosities), of the longer arm are larger than those of the shorter arm, while the lobe width and polarization of the shorter arm are larger than those of the longer arm. The differences are more in quasars, broadline radio galaxies than in the narrow-line radio galaxies and low excitation radio galaxies. Our result generally indicates that beaming plays a role in the structure of more powerful radio sources while environmental factors seems more important in the structure and dynamics of the less powerful radio sources.