(Obscured) Supermassive Black Holes Ezequiel Treister (IfA) Meg Urry, Shanil Virani, Priya Natarajan (Yale) Credit: ESO/NASA, the AVO project and Paolo Padovani The Space Density of CT AGN and the XRB

Supermassive Black Holes Credit: ESO/NASA, the AVO project and Paolo Padovani Many obscured by gas and dust How do we know that?  Local AGN Unification  Explain Extragalactic X-ray “Background”

Compton Thick AGN Defined as obscured sources with N H >10 24 cm -2. Very hard to find (even in X-rays). Observed locally and needed to explain the X-ray background. Number density highly uncertain. High energy (E>10 keV) observations are required to find them.

Swift INTEGRAL

ISDC Swift Sources Tueller et al. 2007

Significance Image, keV Deep INTEGRAL Survey (3 Msec)

Log N-Log S Treister et al. in prep.

Log N-Log S Treister et al. in prep.

Fraction of CT AGN Treister et al. in prep. X-ray background does not constrain density of CT AGN

CT AGN and the XRB CT AGN Space Density Most likely solution Gilli et al Treister et al. in prep.

X-Ray Background Synthesis Treister et al. in prep.

Contribution of CT AGN to the XRB Treister et al. in prep. Only 1% of the XRB comes from CT AGN at z≥2.  We can increase the # of CT AGN by ~10x and still fit the XRB. Only 1% of the XRB comes from CT AGN at z≥2.  We can increase the # of CT AGN by ~10x and still fit the XRB.

CT AGN at High Redshift Treister et al. in prep.

How Many CT AGN? At low redshift (z<0.05), ~5-10 CT AGN from HEAO, BeppoSAX, INTEGRAL, Swift, etc. At high redshift, candidates from X-ray and mid-IR selections. Nothing at intermediate redshifts (z~0.5-1), when most of the XRB is emitted until EXIST, NuSTAR and Simbol-X. At low redshift (z<0.05), ~5-10 CT AGN from HEAO, BeppoSAX, INTEGRAL, Swift, etc. At high redshift, candidates from X-ray and mid-IR selections. Nothing at intermediate redshifts (z~0.5-1), when most of the XRB is emitted until EXIST, NuSTAR and Simbol-X.

CT AGN Space Density (L x >10 45 ) Treister et al. in prep. Polletta+06

Treister et al. in prep. Polletta+06 CT AGN Space Density (L x >10 45 )

Treister et al. in prep. Tozzi+06 Alexander+08 CT AGN Space Density (L x >10 44 )

Treister et al. in prep. Tozzi+06 Alexander+08 CT AGN Space Density (L x >10 44 )

Treister et al. in prep. Tozzi+06 Fiore+08 Risaliti+99 INTEGRAL CT AGN Space Density (L x >10 43 )

Treister et al. in prep. INTEGRAL Tozzi+06 Fiore+08 Risaliti+99 CT AGN Space Density (L x >10 43 )

Treister et al. in prep. Daddi+07 CT AGN Space Density (L x >10 42 )

Treister et al. in prep. Daddi+07 CT AGN Space Density (L x >10 42 ) Mid-IR selection: - No N H - Ref-dominated AGN - Interlopers

SMBHs Spatial Density Natarajan & Treister, 2008

UMBHs Spatial Density Natarajan & Treister, 2008

UMBHs Spatial Density Natarajan & Treister, 2008 Self-Regulation  Momentum-driven winds (Murray et al. 2004).  Radiation pressure (Haehnelt et al. 98)  Energy Driven Superwind (King 05) Self-Regulation  Momentum-driven winds (Murray et al. 2004).  Radiation pressure (Haehnelt et al. 98)  Energy Driven Superwind (King 05)

Summary The number of CT AGN in the local Universe can be constrained, thanks to Swift and INTEGRAL. Number of CT AGN still roughly consistent with XRB, but can be increased by ~4x. Strong decrease in the number of UMBHs -> Self regulation process. (???) The number of CT AGN in the local Universe can be constrained, thanks to Swift and INTEGRAL. Number of CT AGN still roughly consistent with XRB, but can be increased by ~4x. Strong decrease in the number of UMBHs -> Self regulation process. (???)

Observed X-ray “Background” Frontera et al. (2006)

AGN in X-rays Increasing N H Photoelectric absorption affect mostly low energy emission making the observed spectrum look harder.

How to find high-z CT AGN NOW? X-rays? Tozzi et al Trace rest-frame higher energies at higher redshifts  Less affected by obscuration Tozzi et al. claimed to have found 14 CT AGN (reflection dominated) candidates in the CDFS. Polletta et al. (2006) report 5 CT QSOs (transmission dominated) in the SWIRE survey.

Extremely Red X-ray Objects (ERXOs) ERXOs are new class of X-ray emitters about which little is known  7 found in CDFS (Koekemoer et al, 2004)  Defined by very red colors: R-K > 7 (Vega)  Given X-ray detection and very red optical-IR spectrum, either: 1.very high redshift AGN – z > 6 2.very obscured AGN with old or dusty host galaxies at z~2-3 Probably a heterogeneous population?

ERXOs Examples in the ECDF-S Urry et al. in prep.

ECDF-S K band vs Hard X-ray Flux Urry et al. in prep. * ERXOs

Confirming the ERXOs Nature No GALEX or GEMS counterparts NIR spectroscopy crucial to determine the intrinsic nature → no ERXO has a measured spectroscopic redshift 4 ERXOs in ECDFS are bright enough to perform NIR spectroscopy. Targeted with VLT/SINFONI IFU. Three sources observed. No GALEX or GEMS counterparts NIR spectroscopy crucial to determine the intrinsic nature → no ERXO has a measured spectroscopic redshift 4 ERXOs in ECDFS are bright enough to perform NIR spectroscopy. Targeted with VLT/SINFONI IFU. Three sources observed.

Sinfoni Spectroscopy Urry et al. in prep. L x = 4.1x10 44 erg/s  = 1.2±0.4 L x = 2.6x10 43 erg/s  = 1.5±0.4 L x = 1.2x10 43 erg/s  = 1.3±1.0

Fiore et al How to find high-z CT AGN NOW? Mid-IR? X-ray Stacking F 24 /F R >1000 F 24 /F R <200 4  detection in X-ray stack. Hard spectral shape, harder than X- ray detected sources.  Good CT AGN candidates. Similar results found by Daddi et al. (2007)

Energy Range5-600 keV Angular resolution~80” Field of View~half sky CoverageFull sky every 95’ Flux Limit5x (20-50keV) Launch Date???? ~2015 PIJosh Grindlay

NuSTAR Energy Range6-80 keV Angular resolution40” Field of View12’x12’ Flux Limit~2x in 1 Msec Launch DateAugust 2011 PIFiona Harrison