Fabio La Franca

Dipartimento di Fisica

AGN demography and evolutionAGN demography and evolution

Universita` degli Studi ROMA TRE

Schmidt & Green 1983: i primi passi

~200 AGN1

Schmidt & Green 1983

~200 AGN1

Croom+04, 2dF QSO Redshift Survey

~24000 AGN1

20 years after…and two order of magnitude larger samples

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

Parameterization● Quasar LF: double power-law

€

Ψ(L) =Ψ*

(L /L*)β h + (L /L*)β l

€

Ψ(M) =Ψ '*

100.4[M −M * ][β h +1] +100.4[M −M * ][βl+1]

Schmidt & Green 83, ~200 AGN1

Boyle, Shanks & Peterson 88, ~700 AGN1

LF & Cristiani 97 ~ 1200 AGN1

20 years of evolution of the evolutionof the QSO (AGN1) luminosityfunction

Croom+04~24000 AGN1

L(z)=L(0)e6.15

PLE: L(z)=L(0)(1+z)3.4

What’s the Faint End Slope of QLF?

z=0 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.

Hao et al. 2004NLR H and [OIII] LF

Schmidt, Schneider & Gunn 1995

Fan+04 SDSS

High redshift QSO (AGN1) densityoptical (grism) selection

See also Fontanot+07

High redshift QSO (AGN1) densityradio selection

Dunlop & Peacock 90Miller, Peacock & Mead 90

●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

Often rapidly varying:small emission region

Broad spectral energy distribution

High-excitation emission

Before XMM and Chandra:the X-ray LF from ROSAT (Miyaji, Hasinger, Schmidt 2000)0.5-2keV --> mainly AGN1Previous works from Einstein data:e.g. Della Ceca+92

X-ray backgroundthe need for the AGN2/absorbed population

Comastri, Setti, Zamorani, Hasinger 1995

X-ray backgroundthe need for the AGN2/absorbed population

AGN1

AGN2-thin

AGN2-thick

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)

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 2 AGN

Type 1 AGN

There is rough correspondencebetween optical AGN1/AGN2 classificationand column densities

First Spectroscopic identification of Chandra sources

Fiore, LF, Vignali et al. (2000)

XBONG(X-ray Bright Optically Normal Galaxy)

The Lx-z plane and the modeld

LF, Fiore, Comastri+05

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

NH column density distribution

X-ray absorption dependent sky-coverage

Luminosity Dependent Density Evolution (LDDE)

(see previous results fromUeda et al. 2003)

Lower luminosity AGNpeak at lower redshifts:DOWNSIZING(see models of galaxy andAGN formations)

LF, Fiore, Comastri+05

Marconi+04

X-ray AGN LF

Downsizing of AGN activity

– Quasar density peaks at z~2-3

– AGN density peaks at z~0.5 - 1

● Most of BH accretion happens in quasars at high-z● Most of X-ray background in Seyfert 2s at low-z

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

Brusa+09

LDDE found also for optically selected AGN1once the faint end of the LF is probed

Bongiorno, Zamorani+08

See also e.g. Fontanot+07, Shankar & Mathur 07

Downsizing in all bandsHopkins, Richards & Hernquist (2007)

Bongiorno+10 find LDDE also for the AGN2 [OIII] LF

General Evolutionary Trends

• And a calculator: www.cfa.harvard.edu/~phopkins/Site/qlf.html

Hopkins, Richards & Hernquist (2007)

The fraction of absorbed AGN as function of LX and z

*) Assuming no luminosity and redshift dependences

assumed *)

predicted

DECREASE WITH LUMINOSITYEarlier 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).

INCREASE WITH THE REDSHIFT

LF, Fiore, Comastri+05

- 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

The fraction of absorbed AGN as function of LX and z

The decrease of absorbed AGN with increasing luminosity(possible explanations)

Lamastra, Perola & Matt (2006)

The Receding Torus Model: the opening angleof the torus increases with ionizing luminosity(e.g. Simpson 1998; Lawrence 1991;Grimes et al. 2003)

Model 1 Model 2

The gravitational effects of the BH/Bulge on the molecular gas disk of galaxies

Best fit: assuming L and z dependence

The fraction of absorbed AGN as function of LX and z

L

z

We confirm the evidences of a decrease of the fraction of absorbed AGN with luminosity andfind for the first time an increase of absorbed AGN with redshift.

LF, Fiore, Comastri+05

1815 AGN with intrinsic LX>1042 erg/s

The fraction of absorbed AGN as function of LX and z

Melini, Thesis RmTre, 2009

Z~0.3Z~0.3

Z~0.7Z~0.7Z~1.2Z~1.2

Z~1.8Z~1.8

Z~2.5Z~2.5

Lx~43Lx~43

Lx~44Lx~44

Lx~45Lx~45

Confirmed by: Treister & Urry 06, Ballantyne 06, Hasinger+08, Della Ceca+08See discussion on possible selection effects in Akylas+06

The very hard (14-195 keV) XLF

See also: Beckmann+06 and Sazonov+07using INTEGRAL (20-40 keV)

Tueller, Mushotzky+08 (SWIFT/BAT)

A sample of~500 SWIFT/BATAGN are going tobe investigatedby the INAF/Breraand INAF/Palermo-IASFgroups

Tueller, Mushotzky+08 (SWIFT/BAT)

CT about 20%

Highly obscured

Mildly Compton thick

INTEGRAL survey ~ 100 AGN

Sazonov et al. 2006

The very hard (>20 keV) XLF

Malizia+09 (INTEGRAL/IBIS)

Taking into account theselection effects the NH

distribution is fully compatible with [OIII]selected samples(e.g. Risaliti+99)

Estimate a fractionof CT AGN >25%

The fraction of absorbed AGN as a function of flux

and the synthesis of the CXRB

L & z dependence (LDDE)

LF, Fiore, Comastri+05

Marconi et al. (2004)

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-raybackground are the “fossil” integrated result of theAGN evolution, i.e. of the total of accreted mass andof the total energy released in the Universe via accretion

z=0 BH mass functionX-ray background

Integrated history of accretion

Integrated luminosity history

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

0

0

0

bol

2

bol

20 0 0

( , ) : local BH mass function,

( , ) : QSO luminosity function,

(1 ): efficiency,

(1 )( , ) d d ( , );

local accreted

.

M

M

t

n M t

L t

LM

c

LMn M t dM t L L t

c

ψ

εε

ε

ε ψε

∞ ∞

−=

−=∫ ∫ ∫

&

Total mass density accreted = total local BH mass density

Accretion history of the Universe

Luminosity density

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

Accretion rate density

Bolometric correction (Marconi et al. 04)

ε=0.1, radiative efficiency

Luminosity density evolution

BH mass density evolution

The history of BH mass density accretedduring quasar phase

Yu and Tremaine 2002

QSO mean lifetime

● 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).

'0

'

)( 0

)d,(

)d(d)(

0

MtMn

tL,tLM

M M

ML

t

∫∫ ∫

∞

∞

=ψ

~(3-13)107 yr

Expanding Soltan’s Argument

Fitting QLF with local BHMF

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

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

● 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

Cen

tral eng

ine

Matute, LF, Pozzi+06

The MIR 15um LF from ISO

AGN1: L(z)=L(0)(1+z)2.9

AGN2: L(z)=L(0)(1+z)1.8-2.6

IR surveysDifficult 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

Martinez-Sansigre+05

Georgantopulos+08

Sacchi, LF, Feruglio+09

Stern+05 selection

Lacy+04 selection

MIR selection of AGN

Gruppioni+08

Gruppioni+08

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 orderto measure the column densities

SED library from Polletta+07

MIR selection of CT AGN

CDFS X-rayHELLAS2XMM GOODS 24um galaxies

COSMOS X-ray COSMOS 24um galaxies

R-K

Fiore+08 Fiore+09

Open symbols = unobscured AGNFilled symbols = optically obscured AGN* = photo-z

see also Daddi+07

MIR AGNsFiore+08+09

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

Sacchi, LF+09 VLT observationsshowed that about 70% of the300<X/R<1000 DOGs have anAGN optical spectrum

Sacchi, LF, Feruglio+09See also Lanzuisi+09

Flu

x 0

.5-1

0 k

eV

(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

Brusa+10

AGN host galaxies

Obscured (no AGN1) AGN in themost massive and redder galaxies

A significant fraction of obscuredAGN live in massive, dusty star-forminggalaxies with red optical colors

AGN preferentially residein the red sequence andin the “green valley”(Nandra+07, Silverman+08,Hickox+09)

Z>3 AGN countsLower bound: 22 spectro-zUpper-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 outTightest constraints to date (largest and cleanest sample)

Models: Gilli, Comastri & Hasinger 2007, A&A

Space densities

Red curve: predictionslogLx>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

La Franca+05

La Franca+05 (& Brusa+09 at z>2.7)

Brusa+09

X

L 1.4GHz/LX

P(R| LX, z) from LF, Melini & Fiore, ApJ, subm

=

The radio LF and the sub-mJy radio counts

The sub-mJy radio counts and the radio LF

LF, Melini & Fiore, ApJ, subm

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 decreasingluminosity

-Integrating the AGN LF, the CXRB and the local BH massfunction 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 anAGN like SED in the MIR.

-SWIFT and INTEGRAL have not found column densities significantlydifferent 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 roughagreement with the AGN1 evolution in the optical (and radio)