1. AGN demography and evolution
Fabio La Franca
Dipartimento di Fisica
Universita` degli Studi ROMA TRE

2. Schmidt & Green 1983: i primi passi
~200 AGN1

3. 20 years after…and two order of magnitude larger samples
Schmidt & Green 1983
Croom+04, 2dF QSO Redshift Survey
~24000 AGN1
~200 AGN1

4. Parameterization SIMPLE POINTS:
There is no difference in PDE vs. PLE for power-law LF;
But LF will eventually turn over for the total number to converge;
The real LF is likely more complex

5. Parameterization
Quasar LF: double power-law

6. PLE: L(z)=L(0)(1+z)3.4 L(z)=L(0)e6.15
Schmidt & Green 83, ~200 AGN1
20 years of evolution of the evolution
of the QSO (AGN1) luminosity
function
Boyle, Shanks & Peterson 88, ~700 AGN1
LF & Cristiani 97
~ 1200 AGN1
Croom+04
~24000 AGN1
L(z)=L(0)e6.15
PLE: L(z)=L(0)(1+z)3.4

7. What’s the Faint End Slope of QLF?
Hao et al. 2004
NLR H and [OIII] LF
Faint slope measurement
Ranges from -1.o to -2.0…
lead to large uncertainties in
in the total luminosity and
mass density of quasar pop.
z=0

8. High redshift QSO (AGN1) density optical (grism) selection
Schmidt, Schneider & Gunn 1995
Fan+04
SDSS
See also Fontanot+07

9. High redshift QSO (AGN1) density
radio selection
Miller, Peacock & Mead 90
Dunlop & Peacock 90

10. Often rapidly varying: small emission region
Broad spectral energy distribution
High-excitation emission
Non-stellar emission produced at the core of a galaxy (not always visible at optical wavelengths)
Broad wavelength SED: bright from X-rays (even gamma rays) to radio wavelengths, unlike stars
High-excitation emission lines not found in star-forming galaxies
Sometimes highly variable, indicating very compact emission region

11. Before XMM and Chandra:
the X-ray LF from ROSAT
(Miyaji, Hasinger, Schmidt 2000)
0.5-2keV --> mainly AGN1
Previous works from Einstein data:
e.g. Della Ceca+92

12. the need for the AGN2/absorbed population
X-ray background
the need for the AGN2/absorbed population

13. the need for the AGN2/absorbed population
X-ray background
the need for the AGN2/absorbed population
AGN1
AGN2-thin
AGN2-thick
Comastri, Setti, Zamorani, Hasinger 1995
Some other CXRB synthesis models: Matt & Fabian (94); Madau, Ghisellini & Fabian (94);
Gilli+99; Pompilio, LF & Matt (1996); Treister & Urry (05); Gilli, Comastri & Hasinger (07)

14. X-ray Evidence for Absorption
X-ray observations show Type 2 AGNs have larger column densities of gas than Type 1 AGNs (they are more absorbed)
Type 1 AGN
Type 2 AGN
There is rough correspondence
between optical AGN1/AGN2 classification
and column densities

15. First Spectroscopic identification of Chandra sources
XBONG
(X-ray Bright Optically Normal Galaxy)
Fiore, LF, Vignali et al. (2000)

16. The Lx-z plane and the modeld
LF, Fiore, Comastri+05

17. The fitting method
The number of observed AGN in the LX-z space is compared with the number of expected AGN taking into account: 1) a spectroscopic completeness correction, and 2) and an NH distribution and corresponding X-ray absorption effects.
spectroscopic completeness correction
X-ray absorption dependent sky-coverage
NH column density distribution

18. Luminosity Dependent Density Evolution (LDDE)
(see previous results from
Ueda et al. 2003)
Lower luminosity AGN
peak at lower redshifts:
DOWNSIZING
(see models of galaxy and
AGN formations)
LF, Fiore, Comastri+05
Marconi+04

19. X-ray AGN LF Brusa+09 0.5-2 keV: Hasinger, Miyaji, Schmidt 05
See also:
-Ueda+03 (selection effects included)
-Barger+05
-Silverman+08
-Della Ceca+08
-Ebrero+09 (selection effects included)
-Yencho+09
-Aird+10
Downsizing of AGN activity
Quasar density peaks at z~2-3
AGN density peaks at z~
Most of BH accretion happens in quasars at high-z
Most of X-ray background in Seyfert 2s at low-z

20. LDDE found also for optically selected AGN1
once the faint end of the LF is probed
Bongiorno, Zamorani+08
See also e.g. Fontanot+07, Shankar & Mathur 07

21. Downsizing in all bands
Hopkins, Richards & Hernquist (2007)
Bongiorno+10 find LDDE also for the AGN2 [OIII] LF

22. General Evolutionary Trends
Hopkins, Richards & Hernquist (2007)
And a calculator:

23. The fraction of absorbed AGN as function of LX and z
INCREASE WITH THE REDSHIFT
assumed *)
predicted
*) Assuming no luminosity and redshift dependences
DECREASE WITH LUMINOSITY
Earlier evidences of a decrease of the fraction of absorbed AGN with luminosity from Lawrence & Elvis (1982) and Lawrence (1991). Confirmed by Ueda et al. (2003).
LF, Fiore, Comastri+05

24. The fraction of absorbed AGN as function of LX and z
- Type 2 fraction a strong function of luminosity
a) At high (quasar) luminosity: type 2 <20%; optical color selection is highly complete since all are type 1s, and includes most of luminosity AGN population emitted in the Universe
b) At low (Seyfert) luminosity: type 2 ~80%; optical color selection miss most of the AGNs in the Universe in terms of number

25. The decrease of absorbed AGN with increasing luminosity
(possible explanations)
Model 1
Model 2
The Receding Torus Model: the opening angle
of the torus increases with ionizing luminosity
(e.g. Simpson 1998;
Lawrence 1991;
Grimes et al )
The gravitational effects of the BH/Bulge on the molecular gas disk of galaxies
Lamastra, Perola & Matt (2006)

26. The fraction of absorbed AGN as function of LX and z
Best fit: assuming L and z dependence z L
We confirm the evidences of a decrease of the fraction of absorbed AGN with luminosity and
find for the first time an increase of absorbed AGN with redshift.
LF, Fiore, Comastri+05

27. The fraction of absorbed AGN as function of LX and z
1815 AGN with intrinsic LX>1042 erg/s
Lx~45
Lx~44
Z~2.5
Lx~43
Z~1.8
Z~1.2
Z~0.7
Z~0.3
Melini, Thesis RmTre, 2009
Confirmed by: Treister & Urry 06, Ballantyne 06, Hasinger+08, Della Ceca+08
See discussion on possible selection effects in Akylas+06

28. The very hard (14-195 keV) XLF
See also: Beckmann+06 and Sazonov+07
using INTEGRAL (20-40 keV)
Tueller, Mushotzky+08 (SWIFT/BAT)
Tueller, Mushotzky+08 (SWIFT/BAT)
CT about 20%
A sample of
~500 SWIFT/BAT
AGN are going to
be investigated
by the INAF/Brera
and
INAF/Palermo-IASF
groups

29. Highly obscured Mildly Compton thick INTEGRAL survey ~ 100 AGN
Sazonov et al. 2006

30. The very hard (>20 keV) XLF
Malizia+09 (INTEGRAL/IBIS)
Taking into account the
selection effects the NH
distribution is fully
compatible with [OIII]
selected samples
(e.g. Risaliti+99)
Estimate a fraction
of CT AGN >25%

31. The fraction of absorbed AGN as a function of flux
and the synthesis of the CXRB
L & z dependence (LDDE)
LF, Fiore, Comastri+05

32. Both the z=0 BH mass function and the cosmic X-ray
The studies of the local galaxy bulges allow to estimate the z=0 BH mass funtion
Both the z=0 BH mass function and the cosmic X-ray
background are the “fossil” integrated result of the
AGN evolution, i.e. of the total of accreted mass and
of the total energy released in the Universe via accretion
X-ray background
z=0 BH mass function
Integrated luminosity history
Integrated history of accretion
Marconi et al. (2004)

33. Putting things together: Soltan’s argument
Soltan’s argument: QSO luminosity function Y(L,t) traces the accretion history of local remnant BHs (Soltan 1982), if BH grows radiatively
Total mass density accreted = total local BH mass density

34. Accretion history of the Universe
Luminosity density evolution
BH mass density evolution
Luminosity density
Accretion rate density
Bolometric correction
(Marconi et al. 04)
ε=0.1, radiative efficiency
Mass density in BH
Marconi et al. (2004): 4.6 (+1.9;-1.4) M๏ Mpc-3
McLure & Dunlop (2004): 2.8 (+/- 0.4) M๏ Mpc-3

35. The history of BH mass density accreted during quasar phase
Yu and Tremaine 2002

36. QSO mean lifetime
~(3-13)107 yr
The mean lifetime of QSOs is comparable to the Salpeter time (the time for a BH accreting with the Eddington luminosity to e- fold in mass).

37. Expanding Soltan’s Argument
Fitting QLF with local BHMF

38. Evidences for missing SMBH
While the CXB energy density provides
a 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
43-44
Marconi
Menci , Fiore et al. 2004, 2006, 2008

39. Completing 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
Dusty torus
Central engine

40. The MIR 15um LF from ISO AGN1: L(z)=L(0)(1+z)2.9
Matute, LF, Pozzi+06

41. IR surveys Difficult to isolate AGN from star-forming galaxies
(Lacy+04, Barnby+05, Stern+05, Polletta+06, Gruppioni+08, Sacchi, LF, Feruglio+09 and many others). See e.g. discussion of the wedge (Stern) selection in Gorgantopoulos+08 or the analysis by Brusa+10
Georgantopulos+08
Stern+05 selection
Martinez-Sansigre+05
Sacchi, LF, Feruglio+09
Lacy+04 selection

42. MIR selection of AGN SED library from Polletta+07 The problem is:
Gruppioni+08
Gruppioni+08
SED library from Polletta+07
The problem is:
1) to separate the AGN from the galaxy SF contribution:
e.g. Polletta+08, Fritz+06, Pozzi+07+10, Vignali+09
2) Need to deeply observe in the X-ray band in order
to measure the column densities

43. MIR selection of CT AGN R-K Fiore+08 Fiore+09 CDFS X-ray HELLAS2XMM
see also Daddi+07
Fiore Fiore+09
CDFS X-ray
HELLAS2XMM
GOODS 24um galaxies
COSMOS X-ray
COSMOS 24um galaxies
R-K
Open symbols = unobscured AGN
Filled symbols = optically obscured AGN
* = photo-z

44. MIR AGNs
Fiore+08+09
Stack of Chandra images of MIR sources not directly detected in X-rays
F24um/FR>1000 R-K>4.5
logF(1.5-4keV) stacked logLobs(2-8keV) stacked sources ~41.8
log<LIR>~44.8 ==> logL(2-8keV) unabs.~43
Difference implies logNH~24
Sacchi, LF+09 VLT observations
showed that about 70% of the
300<X/R<1000 DOGs have an
AGN optical spectrum
See also Lanzuisi+09
Sacchi, LF, Feruglio+09

45. Flux 0.5-10 keV (cgs) Pizza Plot Area -16 -15 -14 -13 C-COSMOS
HELLAS2XMM
1.4 deg2
Cocchia et al. 2006
Champ 1.5deg2
Silverman 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

46. AGN host galaxies Obscured (no AGN1) AGN in the
most massive and redder galaxies
A significant fraction of obscured
AGN live in massive, dusty star-forming
galaxies with red optical colors
AGN preferentially reside
in the red sequence and
in the “green valley”
(Nandra+07, Silverman+08,
Hickox+09)
Brusa+10

47. Z>3 AGN counts Flat evolution completely ruled out
Lower bound: 22 spectro-z
Upper-bound: adding 10 EXOs
Dashed line:
Expectations from XRB models extrapolating Hasinger+05 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)
Models: Gilli, Comastri & Hasinger 2007, A&A

48. Space densities Red curve: predictions 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
Brusa+09

49. The radio LF and the sub-mJy radio counts
La Franca+05 X
L 1.4GHz/LX
P(R| LX, z) from LF, Melini & Fiore, ApJ, subm =
La Franca+05 (& Brusa+09 at z>2.7)
Brusa+09

50. The sub-mJy radio counts and the radio LF
LF, Melini & Fiore, ApJ, subm

51. SUMMARY
-AGN LF (in the optical, [OIII], X-soft, X-hard bands ) evolves accordingly to
the LDDE model (-->downsizing)
-X-ray obscuration increases with increasing redshift and decreasing
luminosity
-Integrating the AGN LF, the CXRB and the local BH mass
function are fairly well (roughly ?) reproduced
-MIR search for obscured AGN do not seem to find a new (huge)
population of X-ray obscured AGN which clearly show an
AGN like SED in the MIR.
-SWIFT and INTEGRAL have not found column densities significantly
different from expectations (taking into account selection effects)
-The radio AGN LF is in agreement with the XLF if the Radio/X distribution
is taken into account
-X-ray surveys are starting to probe the z>3 XLF which results in rough
agreement with the AGN1 evolution in the optical (and radio)