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Feedback Limits Rapid Growth Seed BHs at High Redshift

Feedback Limits Rapid Growth Seed BHs at High Redshift. Jianmin Wang, Yanmei Chen , Chen Hu Institute of High Energy Physics. Outline. Background and Motivation Growth: Feedback Limit Radiation pressure Compton heating Outflow Discussion Conclusion. Background: observations.

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Feedback Limits Rapid Growth Seed BHs at High Redshift

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  1. Feedback Limits Rapid Growth Seed BHs at High Redshift Jianmin Wang,Yanmei Chen, Chen Hu Institute of High Energy Physics

  2. Outline • Background and Motivation • Growth: Feedback Limit Radiation pressure Compton heating Outflow • Discussion • Conclusion

  3. Background: observations • Early reionization epoch needs a large population of BHs • SDSS indicates that there are BHs with at

  4. Background: two questions • What is the relation between the seed & supermassive BHs? • How to form supermassive BHs?

  5. Background: Rees’ diagram

  6. 108~9 103 Super Eddington accretion SMBH merge Seed BH Background: Volonteri & Rees (2005) One way to form supermassive BHs:

  7. Volonteri & Rees (2005) For MBHs in halos with , the accretion radius is then well within the disc, surrounded by gas with almost constant density , and thus a quasi-spherical geometry

  8. Background: Volonteri & Rees (2005)

  9. 108~9 103 Super Eddington accretion SMBH merge Seed BH feedback Compton Heating Radiation Pressure Outflow Motivation: Can supermassive BHs form with feedback ? feedback

  10. Feedback Limit: radiation pressure The feedback from the radiation pressure is negligible

  11. Feedback Limit: Compton heating Ionization parameter:

  12. Feedback Limit: Compton heating

  13. Feedback Limit : Outflow (Begelman 2004) • Outflow is a generic property of the accretion disk: quasar PG 1211+143 ( Pounds et al. 2003) some X-ray sources (Mukai et al. 2003, Fabbiano et al. 2003) SS 433 (Kotani et al. 1996) • When the outflow is damped by it’s surroundings, its most kinetic energy will dissipate at sonic radius • For a typical outflow, the timescale reaching the sonic point is 33 yr

  14. Discussions • Considering the anisotropic from the slim disk will suppress the Compton heating in some degree. • Some other ways to form supermassive BHs at high redshift ( ) 1、Direct collapse of primordial clouds (Loeb 1993, Loeb & Rossio 1994) 2、Accretion of dark matter will not suffering from feedback (Hu et al. 2005) 3、The inevitable fate of a compact cluster is the formation of a supermassive black hole (Quinlan & Shapiro 1990)

  15. Summary A rapid growth of the seed BH are greatly suppressed and they are hardly able to grow up unless the strong feedback can be avoided, for example considering the anisotropy of the radiation from the tiny accretion disk。

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