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

2. Bolometric Luminosity
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. Bolometric Luminosity
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. Bolometric Luminosity
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-z High spin peak 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:
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