• Unification of Radio Galaxies and their Accretion Jet Properties

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      https://www.ias.ac.in/article/fulltext/joaa/032/01-02/0223-0226

    • Keywords

       

      Black hole physics; accretion; galaxies: jets.

    • Abstract

       

      We investigate the relation between black hole mass, 𝑀bh, and jet power, 𝑄jet, for a sample of BL Lacs and radio quasars. We find that BL Lacs are separated from radio quasars by the FR I/II dividing line in 𝑀bh-𝑄jet plane, which strongly supports the unification scheme of FR I/BL Lac and FR II/radio quasar. The Eddington ratio distribution of BL Lacs and radio quasars exhibits a bimodal nature with a rough division at 𝐿bol/𝐿Edd ∼ 0.01, which imply that they may have different accretion modes. We calculate the jet power extracted from advection-dominated accretion flow (ADAF), and find that it requires dimensionless angular momentum of black hole 𝑗 ≃ 0.9 - 0.99 to reproduce the dividing line between FR I/II or BL Lac/radio quasar if dimensionless accretion rate $\dot{m} = 0.01$ is adopted, which is required by the above bimodal distribution of Eddington ratios. Our results suggest that black holes in radio galaxies are rapidly spinning.

    • Author Affiliations

       

      Qingwen Wu1 Ya-Di Xu2 Xinwu Cao3

      1. Physics Department, Huazhong University of Science and Technology, Wuhan, China.
      2. Physics Department, Shanghai Jiao Tong University, Shanghai, China.
      3. Shanghai Astronomical Observatory, CAS, Shanghai, China.
    • Dates

       
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