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

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

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

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

Radio loudness of quasars?

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

Can we explain the radio luminosity function?

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

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

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

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

Fit to the RLF Leiden, Feb 2011

Best-fitting distributions Leiden, Feb 2011

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

ADAF component Leiden, Feb 2011

QSO component Leiden, Feb 2011

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

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