AGN deep multiwavelength AGN deep multiwavelength surveys:surveys:
the case of the Chandra Deep Field South the case of the Chandra Deep Field South
AGN deep multiwavelength AGN deep multiwavelength surveys:surveys:
the case of the Chandra Deep Field South the case of the Chandra Deep Field South
Fabrizio FioreFabrizio FioreSimonetta Puccetti, Giorgio LanzuisiSimonetta Puccetti, Giorgio Lanzuisi
Table of contentTable of content Introduction
Big scenario for structure formation: AGN & galaxy co-evolution
SMBH census: search for highly obscured AGN X-ray surveys
Unobscured and moderately obscured AGN density Infrared surveys
Compton thick AGN CDFS 2Msec observation: the X-ray view of IR
bright AGN: Spectra of IR sources directly detected in X-rays X-ray “stacking” analysis of the sources not directly
detected.
Introduction Big scenario for structure formation: AGN & galaxy
co-evolution SMBH census: search for highly obscured AGN
X-ray surveys Unobscured and moderately obscured AGN density
Infrared surveys Compton thick AGN
CDFS 2Msec observation: the X-ray view of IR bright AGN: Spectra of IR sources directly detected in X-rays X-ray “stacking” analysis of the sources not directly
detected.
Co-evolution of galaxies and SMBHCo-evolution of galaxies and SMBH
Two seminal results:1. The discovery of SMBH in the
most local bulges; tight correlation between MBH and bulge properties.
2. The BH mass density obtained integrating the AGN L.-F. and the CXB ~ that obtained from local bulges
most BH mass accreted during luminous AGN phases!
Most bulges passed a phase of activity:
1) Complete SMBH census, 2) full understanding of AGN
feedback are key ingredients to understand
galaxy evolution
QuickTime™ e undecompressore
sono necessari per visualizzare quest'immagine.
AGN and galaxy co-evolutionAGN and galaxy co-evolution Early on
Strong galaxy interactions= violent star-bursts
Heavily obscured QSOs
When galaxies coalesce accretion peaks QSO becomes
optically visible as AGN winds blow out gas.
Later times SF & accretion
quenched red spheroid,
passive evolution
Early on Strong galaxy
interactions= violent star-bursts
Heavily obscured QSOs
When galaxies coalesce accretion peaks QSO becomes
optically visible as AGN winds blow out gas.
Later times SF & accretion
quenched red spheroid,
passive evolution
To prove this scenario we need to have:
1) Complete SMBH census, 2) Physical models for AGN feedbacks 3) Observational constraints to these models
Evidences for missing SMBH Evidences for missing SMBH While the CXB energy density providesa statistical estimate of SMBH growth, the lack, so far, of focusing instrument above 10 keV (where the CXB energy density peaks), frustrates our effort to obtain a comprehensive picture of the SMBH evolutionary properties.
Gilli et al. 2007
Marconi 2004-2007Menci , Fiore et al. 2004, 2006, 2008
43-44
44-44.5
AGN densityAGN density
43-44
44-44.5
44.5-45.5
>45.5
42-43
La Franca, Fiore et al. 2005Menci, Fiore et al. 2008
Paucity of Seyfert like sources @ z>1 is real? Or, is it, at least partly, a selection effect?
Are we missing in Chandra and XMM surveys highly obscured (NH1024 cm-2) AGN? Which are common in the local Universe…
Paucity of Seyfert like sources @ z>1 is real? Or, is it, at least partly, a selection effect?
Are we missing in Chandra and XMM surveys highly obscured (NH1024 cm-2) AGN? Which are common in the local Universe…
Highly obscured
Mildly Compton thick
INTEGRAL survey ~ 100 AGN
Sazonov et al. 2006
Completing the census of SMBHCompleting the census of SMBH
X-ray surveys: very efficient in selecting
unobscured and moderately obscured AGN
Highly obscured AGN recovered only in ultra-deep exposures
IR surveys: AGNs highly obscured at optical
and X-ray wavelengths shine in the MIR thanks to the reprocessing of the nuclear radiation by dust
X-ray surveys: very efficient in selecting
unobscured and moderately obscured AGN
Highly obscured AGN recovered only in ultra-deep exposures
IR surveys: AGNs highly obscured at optical
and X-ray wavelengths shine in the MIR thanks to the reprocessing of the nuclear radiation by dust
Dusty
torus
Central engine
X-ray-MIR surveysX-ray-MIR surveys CDFS-Goods MUSIC catalog (Grazian et al. 2006, Brusa, FF et al. 2008) Area
0.04 deg2 ~200 X-ray sources, 2-10 keV down to 210-16 cgs, 0.5-2 keV down to 510-17
cgs 150 spectroscopic redshifts 1100 MIPS sources down to 40 Jy, 3.6m detection down to 0.08 Jy Ultradeep Optical/NIR photometry, R~27.5, K~24 ELAIS-S1 SWIRE/XMM/Chandra survey (Puccetti, FF et al. 2006, Feruglio,FF et
al. 2007, La Franca, FF et al. 2008). Area 0.5 deg2 500 XMM sources, 205 2-10 keV down to 310-15 cgs, >half with spectroscopic
redshifts. 2600 MIPS sources down to 100 Jy, 3.6m detection down to 6 Jy Relatively deep Optical/NIR photometry, R~25, K~19 COSMOS XMM/Chandra/Spitzer. Area ~1 deg2
~1700 Chandra sources down to 610-16 cgs, >half with spectroscopic redshifts. 900 MIPS sources down to 500 Jy, 3.6m detection down to 10 Jy, R~26.5 In future we will add: CDFS-Goods, Chandra 2Msec observation CDFN-Goods COSMOS deep MIPS survey
CDFS-Goods MUSIC catalog (Grazian et al. 2006, Brusa, FF et al. 2008) Area 0.04 deg2
~200 X-ray sources, 2-10 keV down to 210-16 cgs, 0.5-2 keV down to 510-17 cgs 150 spectroscopic redshifts
1100 MIPS sources down to 40 Jy, 3.6m detection down to 0.08 Jy Ultradeep Optical/NIR photometry, R~27.5, K~24 ELAIS-S1 SWIRE/XMM/Chandra survey (Puccetti, FF et al. 2006, Feruglio,FF et
al. 2007, La Franca, FF et al. 2008). Area 0.5 deg2 500 XMM sources, 205 2-10 keV down to 310-15 cgs, >half with spectroscopic
redshifts. 2600 MIPS sources down to 100 Jy, 3.6m detection down to 6 Jy Relatively deep Optical/NIR photometry, R~25, K~19 COSMOS XMM/Chandra/Spitzer. Area ~1 deg2
~1700 Chandra sources down to 610-16 cgs, >half with spectroscopic redshifts. 900 MIPS sources down to 500 Jy, 3.6m detection down to 10 Jy, R~26.5 In future we will add: CDFS-Goods, Chandra 2Msec observation CDFN-Goods COSMOS deep MIPS survey
40
arcmi
n
52
arcmin
z = 0.73 structure
z-COSMOS faint
Color: XMM first year
Full COSMOS field
Chandra deep and wide fieldsChandra deep and wide fieldsCDFS 2Msec 0.05deg2 CCOSMOS 200ksec 0.5deg2 100ksec 0.4deg2
~400 sources 1.8 Msec ~1800 sources Elvis et al. 2008
20 arcmin 1 deg
AGN directly detected in X-raysAGN directly detected in X-rays
Open circles=logNH>23 Open squares = MIR/O>1000 sources
(Tozzi et al. 2003)
MIR selection of CT AGNMIR selection of CT AGN
ELAIS-S1 obs. AGN ELAIS-S1 24mm galaxies HELLAS2XMMCDFS obs. AGN
Fiore et al. 2003
Open symbols = unobscured AGNFilled symbols = optically obscured AGN
Unobscured obscured
X/0
MIR/O
MIR selection of CT AGNMIR selection of CT AGN
CDFS X-rayHELLAS2XMM GOODS 24um galaxies
COSMOS X-ray COSMOS 24um galaxies
R-K
Fiore et al. 2008a Fiore et al. 2008b
Open symbols = unobscured AGNFilled symbols = optically obscured AGN* = photo-z
GOODS MIR AGNsGOODS MIR AGNs
Fiore et. al. 2008a
Stack of Chandra images of MIR sources not directly directly detected in X-rays
F24um/FR>1000 R-K>4.5logF(1.5-4keV) stacked sources=-17 @z~2 logLobs(2-8keV) stacked sources ~41.8log<LIR>~44.8 ==> logL(2-8keV) unabs.~43Difference implies logNH~24
F24/FR>1000 R-K>4.5 <SFR-IR>~200!! Msun/yr <SFR-UV>~7!! Msun/yr <SFR-X>~65 Msun/yrF24um/FR<200 R-K>4.5 <SFR-IR> ~ 18 Msun/yr
<SFR-UV> ~13 Msun/yr
<SFR-X>~20 Msun/yr
F24/FR>1000 R-K>4.5 <SFR-IR>~200!! Msun/yr <SFR-UV>~7!! Msun/yr <SFR-X>~65 Msun/yrF24um/FR<200 R-K>4.5 <SFR-IR> ~ 18 Msun/yr
<SFR-UV> ~13 Msun/yr
<SFR-X>~20 Msun/yr
Program of the project (1) Program of the project (1)
Selection of IR sources with X-ray detection which are likely to host a highly obscured AGN
Extraction of the Chandra spectra of these sources from the event files
Characterization of the X-ray spectra: estimate of the absorbing column density
Evaluation of systematic errors: Background evaluation Combination of data from
different observations
Selection of IR sources with X-ray detection which are likely to host a highly obscured AGN
Extraction of the Chandra spectra of these sources from the event files
Characterization of the X-ray spectra: estimate of the absorbing column density
Evaluation of systematic errors: Background evaluation Combination of data from
different observations
Program of project (2)Program of project (2) Selection of IR
sources without a direct X-ray detection which are likely to host a highly obscured AGN
‘Stacking’ of X-ray images at the position of these sources
Analysis of the ‘stacked’ images
Selection of IR sources without a direct X-ray detection which are likely to host a highly obscured AGN
‘Stacking’ of X-ray images at the position of these sources
Analysis of the ‘stacked’ images
X-ray (and multiwavelength) surveys
X-ray (and multiwavelength) surveys
Fabrizio FioreFabrizio Fiore
Table of contentTable of content
A historical perspective Tools for the interpretation of survey data
Number counts Luminosity functions
Main current X-ray surveys What next
A historical perspective Tools for the interpretation of survey data
Number counts Luminosity functions
Main current X-ray surveys What next
A historical perspectiveA historical perspective First survey of cosmological objects:
radio galaxies and radio loud AGN The discovery of the Cosmic X-ray
Background The first imaging of the sources making
the CXB The resolution of the CXB What next?
First survey of cosmological objects: radio galaxies and radio loud AGN
The discovery of the Cosmic X-ray Background
The first imaging of the sources making the CXB
The resolution of the CXB What next?
Radio sources number counts
First results from Cambridge surveys during the 50’: RyleNumber counts steeper than expected from Euclidean universe
Number countsFlux limited sample: all sources in a given region of the sky with flux > thansome detection limit Flim.
• Consider a population of objects with the same L • Assume Euclidean space
€
n(r) = space density; dN(r) = n(r)dV = n(r)r2drdΩ total number of sources
dN(r)
dΩ= n(r)r2dr surface density; F =
L
4πr2 Flux; F > Flim rmax =
L
4πFlim
⎛
⎝ ⎜
⎞
⎠ ⎟
1/ 2
N(Flim) =dN
dΩ∫ F > Flim( ) =
dN
dΩ∫ r < rmax( ) n(r)r2dr
0
rmax
∫
Total number of sources per unit solid angle (cumulative distribution)
Uniform density of objects ⇒ n(r) = n0
N(Flim ) = n0
rmax3
3=
n0
3
L
4πFlim
⎛
⎝ ⎜
⎞
⎠ ⎟
3 / 2
log N(Flim )( ) = logn0L
3 / 2
3 4π( )3 / 2
⎛
⎝ ⎜ ⎜
⎞
⎠ ⎟ ⎟−
3
2log Flim( ) ⇒ α = −1.5
Number counts
Test of evolution of a source population (e.g. radio sources). Distances of individual sources are not required, just fluxes or magnitudes: the number of objects increases by a factor of 100.6=4 with each magnitude.So, for a constant space density, 80% of the sample will be within 1 mag from the survey detection limit.
( ) ( )
( ) m. N(m)mF
m . -F F.m
60log 6.0log2
3
40log so log52
lim
limlim
∝⇒=−
∝−∝
If the sources have some distribution in L:
€
n(r,L)drdL = n(r)Φ(L)drdL
Φ(L)dL ≡ Luminosity Function
N(r) = n(r,L)r 2drdL =0
rmax(L)
∫∫ n0
34πFlim( )
−3/ 2L3/ 2∫ Φ(L)dL
Problems with the derivation of the number counts
• Completeness of the samples.
• Eddington bias: random error on mag measurements can alter the number counts. Since the logN-logFlim are steep, there are more sources at faint fluxes, so random errors tend to increase the differential number counts. If the tipical error is of 0.3 mag near the flux limit, than the correction is 15%.
• Variability.
• Internal absorption affects “color” selection.
• SED, ‘K-correction’, redshift dependence of the flux (magnitude).
Galaxy number counts
Optically selected AGN number counts
z<2.2B=22.5 100 deg-2
B=19.5 10 deg-2
z>2.2B=22.5 50 deg-2
B=19.5 1 deg-2
B-R=0.5
X-ray AGN number counts
<X/O> OUV sel. AGN=0.3
R=22 ==> 310-15 1000deg-2 R=19 ==> 510-14 25deg-2
The surface density of X-ray selected AGNis 2-10 times higher than OUV selected AGN
The cosmic backgrounds energy densities
The Cosmic X-ray BackgroundThe Cosmic X-ray BackgroundGiacconi (and collaborators) program:1962 sounding rocket1970 Uhuru1978 HEAO11978 Einstein1999 Chandra!
The Cosmic X-ray BackgroundThe Cosmic X-ray Background The CXB energy density: Collimated instruments:
1978 HEAO1 2006 BeppoSAX PDS 2006 Integral 2008 Swift BAT
Focusing instruments: 1980 Einstein 0.3-3.5 keV 1990 Rosat 0.5-2 keV 1996 ASCA 2-10 keV 1998 BeppoSAX 2-10 keV 2000 RXTE 3-20 keV 2002 XMM 0.5-10 keV 2002 Chandra 0.5-10 keV 2012 NuSTAR 6-100 keV 2014 Simbol-X 1-100 keV 2014 NeXT 1-100 keV 2012 eROSITA 0.5-10 keV 2020 IXO 0.5-40 keV
The CXB energy density: Collimated instruments:
1978 HEAO1 2006 BeppoSAX PDS 2006 Integral 2008 Swift BAT
Focusing instruments: 1980 Einstein 0.3-3.5 keV 1990 Rosat 0.5-2 keV 1996 ASCA 2-10 keV 1998 BeppoSAX 2-10 keV 2000 RXTE 3-20 keV 2002 XMM 0.5-10 keV 2002 Chandra 0.5-10 keV 2012 NuSTAR 6-100 keV 2014 Simbol-X 1-100 keV 2014 NeXT 1-100 keV 2012 eROSITA 0.5-10 keV 2020 IXO 0.5-40 keV
The V/Vmax test
Marteen Schmidt (1968) developed a test for evolution not sensitive tothe completeness of the sample.Suppose we detect a source of luminosity L and flux F >Flim at a distance
r in Euclidean space:
€
r =L
4πF
⎛
⎝ ⎜
⎞
⎠ ⎟
1/ 2
the same source could have been detected at a distance rmax =L
4πFlim
⎛
⎝ ⎜
⎞
⎠ ⎟
1/ 2
So we can define 2 spherical volumes : V =4πr3
3 ; Vmax =
4πrmax3
3
If we consider a sample of sources distributed uniformly, we expect that half will be found in the inner half of the volume Vmax and half in the outerhalf. So, on average, we expect V/Vmax=0.5
The V/Vmax test
€
V =
4πr3 / 3( )0
rmax
∫Ω
∫ n(r)r2drdΩ
n(r)r2drdΩ0
rmax
∫Ω
∫=
4πn0
3r5dr
0
rmax
∫
n0 r2dr0
rmax
∫
=4π
3
rmax6 /6
rmax3 / 3
=4π
3
rmax3
2 so :
V
Vmax
= 0.5
In an expanding Universe the luminosity distance must be used in placeof r and rmax and the constant density assumption becomes one ofconstant density per unit comuving volume .
∑=
=N
i i
i
zV
zV
V
V
1 maxmax )(
)(
Luminosity function
In most samples of AGN <V/Vmax> > 0.5. This means that the luminosityfunction cannot be computed from a sample of AGN regardless of their z.Rather we need to consider restricted z bins.
maxmax
1
)(
:sample limited volumea fromdrawn are sources theIf
V
N
VlL L==ΔΦ ∑
More often sources are drawn from flux-limited samples, and the volumesurveyed is a function of the Luminosity L. Therefore, we need to accountfor the fact that more luminous objects can be detected at larger distances and are thus over-represented in flux limited samples. This is done by weighting each source by the reciprocal of the volume over whichit could have been found:
∑=Φi i zV
dLzL)(
1),(
max
Assume that the intrinsicspectrum of the sourcesmaking the CXB has E=1
I0=9.810-8 erg/cm2/s/sr
’=4I0/c
Optical (and soft X-ray) surveys gives values 2-3 times lower than those obtained from the CXB (and of the F.&M. and G. et al. estimates)
Flu
x 0.
5-10
keV
(cg
s)
Area
HELLAS2XMM 1.4 deg2
Cocchia et al. 2006Champ 1.5deg2Silverman et al. 2005
XBOOTES 9 deg2
Murray et al. 2005, Brand et al. 2005
XMM-COSMOS 2 deg2
-16
-15
-14
-13
CDFN-CDFS 0.1deg2 Barger et al. 2003; Szokoly et al. 2004
EGS/AEGIS 0.5deg2
Nandra et al. 2006
SEXSI 2 deg2 Eckart et al. 2006
C-COSMOS 0.9 deg2
E-CDFS 0.3deg2
Lehmer et al. 2005
ELAIS-S1 0.5 deg2
Puccetti et al. 2006
Pizza Plot
A survey of X-ray surveysA survey of X-ray surveys
A survey of X-ray surveysA survey of X-ray surveys
Point sources Clusters of galaxies
A survey of surveysA survey of surveysMain areas with large multiwavelength coverage:
CDFS-GOODS 0.05 deg2: HST, Chandra, XMM, Spitzer, ESO, Herschel, ALMA
CDFN-GOODS 0.05 deg2: HST, Chandra, VLA, Spitzer, Hawaii, Herschel
AEGIS(GS) 0.5 deg2: HST, Chandra, Spitzer, VLA, Hawaii, Herschel
COSMOS 2 deg2: HST, Chandra, XMM, Spitzer, VLA, ESO, Hawaii, LBT, Herschel, ALMA
NOAO DWFS 9 deg2 : Chandra, Spitzer, MMT, Hawaii, LBT SWIRE 50 deg2 (Lockman hole, ELAIS, XMMLSS,ECDFS):
Spitzer, some Chandra/XMM, some HST, Herschel
eROSITA! 20.000 deg2 10-14 cgs 200 deg2 310-15 cgs
Main areas with large multiwavelength coverage:
CDFS-GOODS 0.05 deg2: HST, Chandra, XMM, Spitzer, ESO, Herschel, ALMA
CDFN-GOODS 0.05 deg2: HST, Chandra, VLA, Spitzer, Hawaii, Herschel
AEGIS(GS) 0.5 deg2: HST, Chandra, Spitzer, VLA, Hawaii, Herschel
COSMOS 2 deg2: HST, Chandra, XMM, Spitzer, VLA, ESO, Hawaii, LBT, Herschel, ALMA
NOAO DWFS 9 deg2 : Chandra, Spitzer, MMT, Hawaii, LBT SWIRE 50 deg2 (Lockman hole, ELAIS, XMMLSS,ECDFS):
Spitzer, some Chandra/XMM, some HST, Herschel
eROSITA! 20.000 deg2 10-14 cgs 200 deg2 310-15 cgs
40
arcmi
n
52
arcmin
z = 0.73 structure
z-COSMOS faint
Color: XMM first year
Full COSMOS field
Chandra deep and wide fieldsChandra deep and wide fieldsCDFS 2Msec 0.05deg2 CCOSMOS 200ksec 0.5deg2 100ksec 0.4deg2
~400 sources 1.8 Msec ~1800 sources Elvis et al. 2008
20 arcmin 1 deg
XMM surveysXMM surveysCOSMOS 1.4Msec 2deg2
Lockman Hole 0.7Msec 0.3deg2
Chandra surveysChandra surveysAEGIS: Extended Groth Strip Bootes field
Spitzer large area surveys: SWIRE
Spitzer large area surveys: SWIRE
Elais-N1 Elais-N2
XMM-LSS
Elais-S1
Lockman Hole
eROSITAeROSITA
~30ks on poles, ~1.7ksec equatorial
What next? The X-ray survey discovery space
What next? The X-ray survey discovery space
-13 -15 -17 cgs
log Sensitivity
log
Ene
rgy
rang
e
1
10
100
keV
Log
Area
deg2
4
2
0
Einstein ROSATEinstein ROSAT
ROSAT ROSAT eROSITAeROSITA
ASCA/BSAX ASCA/BSAX XMM ChandraXMM Chandra IXOIXO
IXOIXO
NS NeXT SXNS NeXT SX
BSAX/ASCA BSAX/ASCA XMMXMMSwiftSwift