Transcript Slide 1

Evolution of Supermassive
Black Holes from deep &
large area X-ray surveys
Marcella Brusa
(Max Planck Institut fuer
Extraterrestrische Physik)
Outline
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Introduction: AGN evolution
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What we know: observations & models
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Still missing (among others..):
 high-redshift population
 Compton Thick AGN census
Summary & future
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Main actors in this game
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XMM/Chandra COSMOS teams
CDFS/GOODS/MUSIC team
ELAIS-S1 team
HELLAS2XMM team
.. and in particular thanks to:
A.Comastri, F.Fiore, R.Gilli, A.Bongiorno, N.Cappelluti,
F.Civano, G.Hasinger, K. Iwasawa, V. Mainieri, A.
Merloni, M. Mignoli, S.Puccetti, M.Salvato, C. Vignali,
G.Zamorani, C.Feruglio, A.Grazian, F.LaFranca, F.Pozzi,
P.Santini…
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introduction AGN evolution
Once upon a time… (1960s-70s):
QSO/AGN are triggered by accretion on SMBH
QSO/AGN are 1% of galaxy population:
 transient phase or rare objects?
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[45 years of observations]
Nowadays:
SMBH can be revealed in almost 100% of local
galaxies
AGN transient phase!
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Co-evolution of galaxies and SMBH
MAIN OBSERVATIONAL RESULT: The discovery of dead SMBH in
most local bulges & tight correlation between MBH and bulge properties
Ferrarese & Merritt 2000
Gebhardt et al. 2000
Marconi & Hunt 2003
Marconi &
Hunt 2003
Large scale Galaxy properties strongly depend on BH mass
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AGN and galaxy co-evolution
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Early on
Strong galaxy interactions;
Mergers between gas rich
galaxies drive gas which fuel
both SF and BH activity;
Violent starbursts episodes;
Heavily obscured
BH this
growth
To prove
scenario
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Li et al. 2007
we need:
When galaxies
1) Complete SMBH census,
coalesce
Accretion2)
peaks;
Physical models for AGN feedbacks
SMBH becomes optically
3) Observational
constraints to these models
“visible” (QSO
phase) as
AGN winds blow out gas
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Later times
SF & BH accretion quenched;
Dead quasars (or slowly
accreting BH) in red
galaxies (passive evolution)
[see also Granato+2004, Di Matteo,
Springel & Hernquist 05, Hopkins+07]
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How to study AGN evolution?
Count and detect AGN at different phase/stages of
their evolution
 Surveys
 Accretion Luminosity is emitted over a broad range of
wavelengths, BUT the X-ray emission is the AGN
footprint
 X-ray surveys
 AGN come in 2 flavours: unobscured and
obscured,obscuration affects mostly the soft X-ray
and optical wavelengths
 Hard (>2 keV) X-ray surveys (unbiased)
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Multiwavelength follow-up (redshifts!)
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Evolution of Obscured AGN – why
bother? (1) XRB fit
Gilli, Comastri, Hasinger 07
Red -> unobscured AGN
Blue + Black -> obscured AGN
Obscured AGN
are needed to
reproduce the XRB
peak
[e.g. Setti & Woltjer 1989
…….
Gilli, Comastri & Hasinger 2007]
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Evolution of Obscured AGN – why
bother? (2) BH growth
(Soltan 1982)
Soltan’s argument:
mass accreted is equal to the energy
released (E = mc2…)
IF all galaxies undergo an AGN phase
and
IF dead SMBH observed today are the remnants/witnesses of this phase
 The BH mass density obtained integrating the luminosity emitted by
AGN over the cosmic time is expected to be similar to that measured
in local bulges
ρ(direct) ~ ρ ● ~ 3-5.5 x 105 M⊙ Mpc-3
INCLUDING ALSO
OBSCURED / CT AGN
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[see e.g. Shankar et al. 2008
Marconi et al. 2004, Fabian 2003,
Fabian & Iwasawa 1999 etc]
Survey of surveys - X-rays + multiwave
CDFN-CDFS 0.1deg2
Barger et al. 2003; Szokoly et al. 2004
Flux 2-10 keV (cgs)
-16
E-CDFS 0.3deg2
Lehmer et al. 2005
C-COSMOS 0.9 deg2
Lockman Hole 0.2 deg2
Brunner et al. 2008
EGS/AEGIS 0.5deg2
Nandra et al. 2006
Contiguous
-15
-14
XMM-COSMOS 2 deg2
ELAIS-S1 0.5deg2
Puccetti et al. 06, Feruglio et al. 08
SEXSI 2 deg2
Eckart et al. 2006
HELLAS2XMM 1.4 deg2
Fiore et al. 20003
Cocchia et al. 2006
Champ 1.5deg2
Silverman et al. 2005
-13
(see Brandt & Hasinger 2005 ARA&A 43, 827)
XMM HBS ~25 deg2
Della Ceca+04,08
XBOOTES 9 deg2
Murray et al. 2005,
Brand et al. 2005
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Area
Evolution
Hasinger+05
Fiore +03
La Franca +05

Bongiorno+07
picture quite clear from optical/soft/hard X-ray surveys:
Luminosity-Dependent Density Evolution (LDDE)
[see also Ueda+03, Cirasuolo+05, Della Ceca+08]

Anti-hierarchical growth/Downsizing
[Cowie et al. 1996, Merloni 2004, De Lucia et al. 2006]
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Fraction of absorbed sources:
Luminosity dependence
Black: X-ray
Hasinger 2008
Hasinger et al. 2005
(see also
La Franca +05, Treister+05, Della Ceca+08)
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Green: IR
Maiolino et al. 2007
Red: Optical
Simpson et al. 2005
fraction of obscured AGN is a strong function of L: most luminous,
less obscured
Same result in DIFFERENT bands despite the very different
selections!!
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Fraction of absorbed sources:
Redshift dependence
La Franca +05

more debated!
Hasinger 2008
Seen in (some) data [e.g. La Franca+05, Treister+06, Hasinger08],
not seen in others (Ueda+03, Dwelly&Page 2006), not needed in XRB
models (Gilli+07) but expected/predicted in feedback models
(Menci+08)
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Still missing (open problems)
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Compton Thick objects / census
number density and evolution of high-z
population (z>3)
Interplay between AGN and SF / feedback models
[see Marulli/Fontanot]
Bolometric output/reprocessing [see Severgnini/Bellocchi/Lusso]
BH mass / accretion rate evolution [see Labita]
Elusive AGN (e.g. XBONGs/EXOs) [see Civano/Del Moro/Lanzuisi]
Role of the envinronment in triggering nuclear activity
[e.g. results from AEGIS/Groth strip – Georgakakis+07,08]
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The population of z>3 QSOs
(XMM-COSMOS)
Brusa, Comastri, Gilli et al. 2008, ApJ, submitted
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The population of z>3 QSO
Radio QSO
(Wall et al., 2005)
Optical QSOs
(Schmidt et al., 1995, Fan et al.
2001,2004)
COSMOS
?
X-ray: What happens at z>3?
decline or ~costant ?
Soft X-ray ROSAT/Chandra/ XMM
(Hasinger, Miyaji & Schmidt 2005)
Chandra/ROSAT
(Silverman et al. 2005/2007)
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statistics still low at z~3-5
(NO statistics at z>6)
Cosmos
Survey
2 deg2 (PI: N. Scoville)
>150 team members
worldwide!
COSMOS major components (in order
of appearance) :
XMM-Newton
PI: G. Hasinger
HST/ACS (I-band – 590 orbits – I(AB)~27)
2002-2003:
Subaru imaging (~25 nights - b,v,r,i,z=26/27)
VLA (265 hours – 24 μJy)
GALEX deep (200 ks, AB~25)
XMM-Newton (800 ks – 10-15 cgs)
2004-2005:
XMM-Newton (600 ks)
VLT (540 hours) & Magellan (12+ nights)
SPITZER-IRAC (200 hours - ~1 μJy)
2006:
SPITZER-MIPS (200 hours - ~70 μJy)
Chandra (1.8 Ms)
http://cosmos.astro.caltech.edu
+ MAMBO,
ApJS special issue vol. 172 (>550
pages!) CFHT, Bolocam and (future) others
http://www.astro.caltech.edu/cosmos/
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soft 0.5-2.0 keV
medium 2.0-4.5 keV
hard 4.5-10.0 keV
Hasinger et al. 2007
AGN redshift distribution in
XMM-COSMOS
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X-ray sample (AGN)
Empty: specz+photz
Filled: specz
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Sources extracted from a flux
limited sample in XMM-COSMOS
(50% of the area coverage in at least
one band)
1651 XMM sources
- 10% problematic ID using
IR+Chandra info
~670 “secure” spectroscopic
redshifts (40%), incompleteness
especially for high-z and Type 2
AGN
Accurate photometric redshifts
available (Salvato et al. 2008)
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AGN photometric redshifts
434 objects with
“super-secure”
spectro-z (further
refinement/analysis)
Photo-z computed using
>30 bands:
SDSS, Subaru including
IB, CFHT, J, K, IRAC..
LESS than 10%
catastrophic outliers
(to be compared with
COMBO-17, Wolf et al. 2004)
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Salvato et al. (in prep)
AGN redshift distribution in
XMM-COSMOS
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X-ray sample (AGN)
Empty: specz+photz
Filled: specz
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z>3 sample: 40
Sources extracted from a flux
limited sample in XMM-COSMOS
(50% of the area coverage in at least
one band)
1651 XMM sources
- 10% problematic ID using
IR+Chandra info
~670 “secure” spectroscopic
redshifts (40%), incompleteness
especially for high-z and Type 2
AGN
Accurate photometric redshifts
available (Salvato et al. 2008)
objects (22 specz + 18 photoz)
Additional 14 objects, no photoz available. Candidates very high-z AGN (EXOs,
Koekemoer et al. 2004)
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Examples of images, spectra & photoz
XID 54439
z=4.241
B
g
v
r
I
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z
IRAC 3.6
X-ray properties
HR vs.
redshift
Ratio of obscured/
unobscured objects
in agreement
with XRB models
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Contribution to source counts
Lower bound: 22 spectro-z
Upper-bound: adding 10 EXOs
Dashed line:
Expectations from XRB models
using Hasinger et al. 2005 LF
Solid line:
Exponential decay introduced at
z=2.7 (Schmidt+95)
Flat evolution completely
ruled out
Tightest constraints to date
(largest and cleanest sample)
z>4 point:
Models: Gilli, Comastri & Hasinger 2007, A&A
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Rhook & Haenelt 08 predict a factor
of ~3 higher wrt data
Space densities
Red curve:
predictions from XRB models
logLx>44.2 AGN (unobs+obs)
[Gilli+07 using Hasinger+05
and La Franca+05]
Dashed area:
(rescaled) space density for
optically selected bright QSO
[Richards+2006, Fan+2001]
Blue curve:
Silverman+08 LF, I<24 sample
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The census of z~1-3 CT AGN/QSOs
(CDFS+COSMOS)
Fiore et al. 2008a, ApJ, 672, 94
Fiore, Puccetti, Brusa et al. 2008b, ApJ, submitted
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Unveiling obscured accretion
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X-ray surveys:
miss most highly obscured (Compton Thick) AGN
[e.g. Comastri 2004, Worsley et al. 2005]
IR surveys:
highly obscured AGN shine in the MIR – dust reprocessing
[e.g. Martinez-Sansigre et al. 2005, Polletta et al. 2006]
Goal:
combining X-ray and IR surveys to get the SMBH census and
compile AGN bolometric LF
X-ray-MIR surveys:
CDFS/GOODS/MUSIC [Grazian et al. 2006, Brusa et al. in prep, CDFS team papers]
ELAIS-S1/SWIRE [Feruglio et al. 2008, La Franca et al. 2008]
COSMOS [XMM-COSMOS: Brusa et al. 2008; + C-COSMOS/S-COSMOS papers]
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MIR selection of CT AGN
All sources
BL AGN
NOT BL AGN
High MIR/O
Select candidate,
luminous obscured AGN
by imposing:
24 micron bright fluxes
(luminous) +
optically faint red sources
(optically obscured)
high MIR/O ratio
XMM-COSMOS sample
HR distribution [Brusa et al. 2008b]
See also results from ELAIS-S1, Feruglio et al. 2008, Lanzuisi’s talk
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Combining MIR/O and R-K criteria:
selection of CT AGN at z~2
GOODS CDFS field
(1 Ms Chandra data)
+
MUSIC MW catalog
(Spitzer+HST+VLT)
~110 obscured AGN
candidates
Tracks of obscured AGN
Stack of Chandra
images excluding X-ray
detections in two
different MIR/O and
R-K bins
[Pozzi et al 2007]
Fiore et al. 2008a
See also Daddi et al. 2007
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A new population of CT AGN
Daddi et al. 2007
Fiore et al. 2008
Martinez-Sansigre et al. 2005
Polletta et al. 2006
Low R-K or
The observed MIR luminosity
and the observed HR imply
(unobs) Lx>43 and NH>24 for
~80% of the sources
Curves: model predictions from
Gilli, Comastri & Hasinger
(2007) for L> 42, 43, 44, 45
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COSMOS MIR AGN
Fiore et al. 2008b
High AGN fraction (~65%) in MIPS selected samples
(deeper X-ray data + more comprehensive analysis)
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Summary
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The fraction of obscured sources depend
strongly on luminosity
The fraction of obscured sources evolves
(increases) with redshift
Flat evolution at z>3 definitively ruled out
(space densities & number counts)
Significant population of CT QSO at z~2
detected
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What’s next?
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Compton Thick AGN/quasars:
 XMM ultra deep 1.3 Ms (this fall)
 exploit stacking… (Chandra 2 Ms)
 Simbol-X (high-energy)
 Herschel (reprocessing)
High-z quasars:
 eROSITA (high-L)
 XEUS (low-L and very high-redshift)
 joint multiwavelength campaigns
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