1. The History of Black Hole Accretion from X-ray Stacking Ezequiel Treister (IfA, Hawaii) Collaborators: Meg Urry, Priya Natarajan, Kevin Schawinski (Yale), Carie Cardamone (MIT), Eric Gawiser (Rutgers), Dave Sanders (IfA), Marta Volonteri (Michigan) Credit: Treister & Natarajan

2. Swift INTEGRAL Local Universe (z~0)

3. Log N-Log S Treister et al. 2009a

4. Contribution of CT AGN to the XRB Only 0.1% of the XRB comes from CT AGN in the local Universe. Treister et al. 2009a ~10% of the XRB due to CT AGN. XRB not useful to constrain CT AGN at z>1.

5. Fiore et al. 2008, Treister et al. 2009b Mid-IR Intermediate Redshifts (z~1-3) This technique selects mostly high luminosity sources (quasars). All Sources X-ray Detected X-ray Undetected

6. Stacking of f 24 /f R >10 3 Sources Soft (0.5-2 keV)Hard (2-8 keV) - ~4  detection in each band. - f soft =2.1x10 -17 erg cm -2 s -1. f hard = 8x10 -17 erg cm -2 s -1 - Sources can be detected individually in ~10 Msec. Treister et al. 2009b

7. Rest-Frame Stacking N H =10 24 cm -2  =1.9  =1.9 (reflected) Thermal kT=0.7 keV HMXBs Combination of heavily- obscured AGN and star- formation. Treister et al. 2009b

8. The Merger-Quasar Connection Treister et al. 2010a

9. Morphologies Mrk 273NGC 7674 NGC 6240 HUDFGOODS-S Treister et al. 2010a

10. The Merger-Quasar Connection  t=96  23 Myrs The obscured phase represents ~30% of total accretion onto supermassive black holes Treister et al. 2010a Quasars outflows can get rid of most of the surrounding material

11. Lower Luminosity Obscured AGN Treister et al. 2010b CDF-S 4 Msec data!!! X-ray stacking of IR-selected galaxies Harder X-ray spectrum for more luminous sources -> More AGN in these samples.

12. Rest-frame Spectral Analysis Treister et al. 2010b Combination of thermal emission, X-ray binaries and obscured AGN AGN Luminosities -6x10 42 erg/s L IR >10 11 L o -3x10 42 erg/s L IR >5x10 10 L o -5x10 41 erg/s 5x10 10 >L IR (L o )>10 10 -7x10 41 erg/s L IR >10 10 L o Much flatter evolution -> different triggering mechanism?

13. Bouwens et al. 2010 Lyman Break Selection High Redshift (z>7)

14. Treister et al. submitted X-Ray Stacking Soft (0.5-2 keV) 4-16 keV rest-frame Hard (2-8 keV) 16-64 keV rest-frame -CDF-S 4 Msec data -75 sources (300 Msec!!!) -No detection! -Rest frame 2-10 keV average L<4.2x10 41 erg/s -  BH (z>7)<1143M o Mpc -3 (3  )

15. Accreted Mass vs Redshift Observed z=0 BH MF X-ray detected X-ray stackedz>7 stacking Treister et al. submitted

16. Accreted Mass vs Redshift Soltan Argument. X-ray LF More CT quasars Treister et al. submitted

17. Accreted Mass vs Redshift Dir. Coll. Self-regulated Pop III Self-regulated Dir. Coll., no Self-reg. Pop III, no Self-reg Treister et al. submitted

18. Summary Most BH accretion up to z~3 identified in X-rays, either directly or via stacking. Vast majority of accretion, ~70%, is obscured. ~20% of BH accretion is Compton Thick. X-ray background not a strong constrain for heavily- obscured accretion. Self-regulation appears to be important for BHs at all masses. Observations of accreting BHs cannot identify nature of BH seeds.