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The cosmic spin of SMBHs from radio observations

The cosmic spin of SMBHs from radio observations. Alejo Martínez Sansigre (ICG-Portsmouth) & Steve Rawlings (Oxford). Assumptions:. Bolometric Luminosity. Jet power. e.g. Mckinney (2005), Hawley & Krolik (2006), Nemmen et al. (2007), Benson & Babul (2009), Tchekhovskoy et al. (2010).

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The cosmic spin of SMBHs from radio observations

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  1. The cosmic spin of SMBHs from radio observations Alejo Martínez Sansigre (ICG-Portsmouth) & Steve Rawlings (Oxford)

  2. Assumptions: Bolometric Luminosity Jet power e.g. Mckinney (2005), Hawley & Krolik (2006), Nemmen et al. (2007), Benson & Babul (2009), Tchekhovskoy et al. (2010). Leiden, Feb 2011

  3. Assumptions: Bolometric Luminosity Accretion rate Jet power e.g. Mckinney (2005), Hawley & Krolik (2006), Nemmen et al. (2007), Benson & Babul (2009), Tchekhovskoy et al. (2010). Leiden, Feb 2011

  4. Assumptions: Radiative efficiency Bolometric Luminosity Accretion rate Jet power Jet efficiency e.g. Mckinney (2005), Hawley & Krolik (2006), Nemmen et al. (2007), Benson & Babul (2009), Tchekhovskoy et al. (2010). Leiden, Feb 2011

  5. Radio loudness of quasars?

  6. Radio-loudness of quasars Spin Accretion Data from Cirasuolo et al. (2003) Martinez-Sansigre & Rawlings (2011) Leiden, Feb 2011

  7. Can we explain the radio luminosity function?

  8. The radio LF P. Best private communication Leiden, Feb 2011

  9. Modelling the HEGs with QSOs Can convert Lx to accretion rate Silverman et al. (2008) Leiden, Feb 2011

  10. Modelling the LEGs with ADAFs BH mass function Graham et al. (2007) Leiden, Feb 2011

  11. Modelling the LEGs with ADAFs Distribution of Eddington ratios (flat prior due to ignorance) BH mass function Graham et al. (2007) Leiden, Feb 2011

  12. Fit to the RLF Leiden, Feb 2011

  13. Best-fitting distributions Leiden, Feb 2011

  14. Prediction z=1 RLF Radio LFs from Willott et al. (2001) and Smolcic et al. (2009) Martinez-Sansigre & Rawlings (2011) Leiden, Feb 2011

  15. Compare to cosmological simulations Fanidakis et al. (2010) Martinez-Sansigre & Rawlings (2011) Leiden, Feb 2011

  16. Spin history Low-z Low accn rate High spin peak High-z High accn rate All spin low Leiden, Feb 2011

  17. Chaotic accretion + mergers Chaotic accretion leads to low spins Martinez-Sansigre & Rawlings (2011) Leiden, Feb 2011

  18. Chaotic accretion + mergers Chaotic accretion leads to low spins Recent major mergers lead to high spins Martinez-Sansigre & Rawlings (2011) Leiden, Feb 2011

  19. Interpretation • Physically, at z=0 the radio LF is dominated by low-accretion rate objects with high spins • A small fraction, however, originates in high-accretion rate objects with low spin • At higher redshifts, the density of high-accretion low-spin objects increases, an they eventually dominate the radio LF. • This means that the mean spin is higher at low redshift, and lower at high redshift. • This is consistent with the picture of chaotic accretion spinning SMBHs down, and major mergers spinning them up. Leiden, Feb 2011

  20. Thank you! For more info: Martínez-Sansigre & Rawlings, MNRAS (2011), ArXiv: 1102.2228 Leiden, Feb 2011

  21. Parametric forms for spin distribution Power-law distribution Leiden, Feb 2011

  22. Parametric forms for spin distribution Single-gaussian distribution Leiden, Feb 2011

  23. Parametric forms for spin distribution Double gaussian distribution Leiden, Feb 2011

  24. Parametric forms for spin distribution Bayesian evidence chooses the double gaussian Leiden, Feb 2011

  25. Jet efficiency e.g. Mckinney (2005), Hawley & Krolik (2006), Nemmen et al. (2007), Benson & Babul (2009), Tchekhovskoy et al. (2010). Leiden, Feb 2011

  26. Comparison to entire RLF Leiden, Feb 2011 Martinez-Sansigre & Rawlings (2011)

  27. Spin-down: chaotic accretion Infalling gas from the galaxy is NOT expected to all be in the same angular momentum plane Co- or counter-alignment will occur depending on relative J and orientation Overall effect is for chaotic accretion to spin down a rapidly rotating SMBH, typically to a~0.1 King et al. (2006,2008) Leiden, Feb 2011

  28. Spin history Martinez-Sansigre & Rawlings (2011) Leiden, Feb 2011

  29. Spin-up mechanism: BH mergers Major mergers of low spin BHs leads to high spin coalesced BHs. BH merger formula from Rezzolla et al. (2008) Leiden, Feb 2011

  30. Spin-up mechanism: BH mergers Assume a Poisson distribution with a mean of 0.7 major mergers (following Robaina et al. 2010) BH merger formula from Rezzolla et al. (2008) Leiden, Feb 2011

  31. ADAF component Leiden, Feb 2011

  32. QSO component Leiden, Feb 2011

  33. Radiative efficiency Novikov & Thorne (1973), Mckinney & Gammie (2004), Beckwith et al. (2008,) Noble et al. (2009), Penna et al. (2010) Leiden, Feb 2011

  34. Producing jets Figure from: J. Krolik’s webpage Leiden, Feb 2011

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