(obscured) supermassive black holes
DESCRIPTION
The Space Density of CT AGN and the XRB. (Obscured) Supermassive Black Holes. Ezequiel Treister (IfA) Meg Urry, Shanil Virani, Priya Natarajan (Yale). Credit: ESO/NASA, the AVO project and Paolo Padovani. Supermassive Black Holes. Many obscured by gas and dust. How do we know that? - PowerPoint PPT PresentationTRANSCRIPT
(Obscured) Supermassive (Obscured) Supermassive Black HolesBlack Holes
Ezequiel Treister (IfA)Ezequiel Treister (IfA)Meg Urry, Shanil Virani, Priya Natarajan Meg Urry, Shanil Virani, Priya Natarajan
(Yale)(Yale)
Credit: ESO/NASA, the AVO project and Paolo Padovani
The Space Density of The Space Density of CT AGN and the XRBCT AGN and the XRB
Supermassive Black Supermassive Black Holes Holes
Credit: ESO/NASA, the AVO project and Paolo Padovani
Many obscured by gas and dustMany obscured by gas and dust
How do we know that?How do we know that?
Local AGN Unification
Explain Extragalactic X-ray “Background”
Compton Thick AGNCompton Thick AGN
Defined as obscured sources with NH>1024 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.
SwiftSwift INTEGRALINTEGRAL
ISDC
Swift Sources
Tueller et al. 2007
Significance Image, 20-50 keV
Deep INTEGRAL Survey (3 Msec)Deep INTEGRAL Survey (3 Msec)
Log N-Log SLog N-Log S
Treister et al. in prep.
Log N-Log SLog N-Log S
Treister et al. in prep.
Fraction of CT AGNFraction of CT AGN
Treister et al. in prep.
X-ray background does not constrain density of CT AGN
CT AGN and the XRBCT AGN and the XRB
CT AGN Space Density
Most likely solution
Gilli et al. 2007
Treister et al. in prep.
X-Ray Background X-Ray Background SynthesisSynthesis
Treister et al. in prep.
Contribution of CT AGN to the Contribution of CT AGN to the XRBXRB
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 RedshiftCT AGN at High Redshift
Treister et al. in prep.
How Many CT AGN?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 CT AGN Space Density (L(Lxx>10>104545))
Treister et al. in prep.
Polletta+06
Treister et al. in prep.
Polletta+06
CT AGN Space Density CT AGN Space Density (L(Lxx>10>104545))
Treister et al. in prep.
Tozzi+06
Alexander+08
CT AGN Space Density CT AGN Space Density (L(Lxx>10>104444))
Treister et al. in prep.
Tozzi+06
Alexander+08
CT AGN Space Density CT AGN Space Density (L(Lxx>10>104444))
Treister et al. in prep.
Tozzi+06
Fiore+08
Risaliti+99
INTEGRAL
CT AGN Space Density CT AGN Space Density (L(Lxx>10>104343))
Treister et al. in prep.
INTEGRAL
Tozzi+06
Fiore+08
Risaliti+99
CT AGN Space Density CT AGN Space Density (L(Lxx>10>104343))
Treister et al. in prep.
Daddi+07
CT AGN Space Density CT AGN Space Density (L(Lxx>10>104242))
Treister et al. in prep.
Daddi+07
CT AGN Space Density CT AGN Space Density (L(Lxx>10>104242))
Mid-IR selection:- No NH
- Ref-dominated AGN- Interlopers
SMBHs Spatial DensitySMBHs Spatial Density
Natarajan & Treister, 2008
UMBHs Spatial DensityUMBHs Spatial Density
Natarajan & Treister, 2008
UMBHs Spatial DensityUMBHs Spatial Density
Natarajan & Treister, 2008
Self-RegulationSelf-Regulation
Momentum-driven Momentum-driven winds (Murray et winds (Murray et al. 2004).al. 2004).
Radiation Radiation pressure pressure (Haehnelt et al. (Haehnelt et al. 98)98)
Energy Driven Energy Driven Superwind (King Superwind (King 05)05)
Self-RegulationSelf-Regulation
Momentum-driven Momentum-driven winds (Murray et winds (Murray et al. 2004).al. 2004).
Radiation Radiation pressure pressure (Haehnelt et al. (Haehnelt et al. 98)98)
Energy Driven Energy Driven Superwind (King Superwind (King 05)05)
SummarySummary
• 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 Observed X-ray “Background”“Background”
Frontera et al. (2006)
AGN in X-raysAGN in X-rays
Increasing NH
Photoelectric absorptionaffect mostly low energy emission making the observed spectrum look harder.
How to find high-z CT AGN NOW?How to find high-z CT AGN NOW?
X-rays?X-rays?
Tozzi et al. 2006
Trace rest-frame higher energies at higher redshifts Less affected by obscurationTozzi 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 Extremely Red X-ray Objects (ERXOs)(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-SERXOs Examples in the ECDF-S
Urry et al. in prep.
ECDF-S K band vs Hard X-ray FluxECDF-S K band vs Hard X-ray Flux
Urry et al. in prep.
* ERXOs
Confirming the ERXOs NatureConfirming 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 SpectroscopySinfoni Spectroscopy
Urry et al. in prep.
Lx= 4.1x1044 erg/s = 1.2±0.4
Lx= 2.6x1043 erg/s = 1.5±0.4
Lx= 1.2x1043 erg/s = 1.3±1.0
Fiore et al. 2008
How to find high-z CT AGN NOW?How to find high-z CT AGN NOW?
Mid-IR?Mid-IR? X-ray StackingX-ray Stacking
FF2424/F/FRR>1000>1000
FF2424/F/FRR<200<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)
NuSTARNuSTAR