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      Permanent link:
      https://www.ias.ac.in/article/fulltext/joaa/040/01/0006

    • Keywords

       

      Galaxies: active; galaxies: quasars; general.

    • Abstract

       

      In this paper, we use the distributions of luminosity ($P$) and radio size ($D$) to re-examine the consistency of the unified scheme of high-excitation radio galaxies and quasars in the recently updated 3CRR sample. Based on a standard cosmology, we derive theoretically and show from observed data, the luminosity limit above which the 3CRR objects are well-sampled. We find, on average, a quasar fraction $\sim$0.44 and galaxy-to-quasar size ratio $\approx$2. Assuming a relativistic outflow of jet materials, we find a mean angle to the line of sight in the range 35$^{\circ} \leq \phi \leq 44^{\circ}$ for the quasars. On supposition of luminosity and orientation-dependent linear size evolution, expressed in a general functional form $D_{\rm (P,z,\phi)} \approx P^{\pm q}(1+z)^{−w} \sin \phi$, we show that above the flux detection threshold of the 3CRR sample, high-excitation galaxies and quasars undergo similar evolutionwith $q = −0.5$; $w = −0.27$ and luminosity independent evolution parameter $x = 2.27$, when orientation effect is accounted for. The results are consistent with orientation-based unified scheme for radio galaxies and quasars.

    • Author Affiliations

       

      F. C. ODO1 P. E. OKOBI1 J. A. ALHASSAN1 A. A. UBACHUKWU1

      1. Department of Physics and Astronomy, University of Nigeria, Nsukka, Nigeria.
    • Dates

       
  • Journal of Astrophysics and Astronomy | News

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