(Obscured) Supermassive Black Holes Ezequiel Treister (IfA) Meg Urry, Shanil Virani, Priya Natarajan (Yale), Julian Krolik (JHU), Eric Gawiser (Rutgers), Anton Koekemoer (STSCI)

3C-273: Bright Quasar Credit: SDSS

NGC1068: Obscured AGN Credit: SDSS

NGC2595: Non Active Credit: SDSS

SDSS J : ??? Credit: SDSS

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”

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.

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 (Euclidean) Treister et al. in prep.

CT AGN Log N-Log S 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.

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

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)

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 )

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 Apparent lack of CT AGN in the local Universe compared to space density at high-z. Number of CT AGN still roughly consistent with XRB, but can be increased ~4x Strong decrease in the number of UMBHs -> Self regulation process. (???) Apparent lack of CT AGN in the local Universe compared to space density at high-z. Number of CT AGN still roughly consistent with XRB, but can be increased ~4x Strong decrease in the number of UMBHs -> Self regulation process. (???)