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4.6.3 Host galaxies of AGN 4.6.4 The unified model of AGN

4.6.3 Host galaxies of AGN 4.6.4 The unified model of AGN. 28 th Feb. 2007 Skarma Kim. Host galaxies of AGN. Some LINERs reside in the centers of E The majority of these systems appear to be fairly normal spiral galaxies. But radio galaxies are found to be elliptical galaxies.

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4.6.3 Host galaxies of AGN 4.6.4 The unified model of AGN

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  1. 4.6.3 Host galaxies of AGN4.6.4 The unified model of AGN 28th Feb. 2007 Skarma Kim

  2. Host galaxies of AGN • Some LINERs reside in the centers of E • The majority of these systems appear to be fairly normal spiral galaxies. • But radio galaxies are found to be elliptical galaxies

  3. Radio galaxies

  4. Quasar? QSO? • Quasars all seem to be hosted by giant elliptical galaxies. • The morphologies of the QSO host galaxies is less clear-cut: although some of these galaxies are gE, others are probably disk galaxies. • Thus it is not clear whether QSOs are more closely related to quasars or Seyferts. NGC7319

  5. Quasar? QSO? z=5.15, wfsj2245+0024

  6. Interactions with other galaxies • Imaging with HST has revealed multiple nuclei, close companions and tidal tails in several systems

  7. Every rule has an exception • The vast majority of BL Lacs, like other radio-bright AGN, appear to be hosted by elliptical galaxies, but an HST image of one BL Lac, PKS1413+135, reveals that it is located in an edge-on spiral galaxy.

  8. The unified model of AGN

  9. The unified model of AGN • The differences of AGN in observational properties 1) significantly more luminous 2) produce jets 3) a given AGN can have very different observational properties depending on the direction from which one views it

  10. Direct evidence • The emission from ionized material in the core of the seyfert 2 galaxy NGC1068. • The wedge-shaped geometry suggests that the ionizing radiation is being beamed out from an AGN in a cone.

  11. The unified model of AGN

  12. The unified model

  13. Spectrum for the component of the light of NGC1068

  14. Very high dynamic range radio map fo the blazar 3C 371

  15. Eddington luminosity • The power emitted by an AGN is believed to be derived from the accretion of matter on to a BH. • A bright QSO with a luminosity of ~1012L⊙ requires a black hole of mass > 3x107M⊙ • The primary factor which affects the luminosity produced by a given black hole is the rate at which it accretes material

  16. Unsolved problem • Many other questions about AGN are also as yet unresolved. • The fact that radio-loud AGN are generally located in elliptical galaxies while radio-quiet AGN tend to be found in spirals must be relevant.

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