Castel Gandolfo, Ottobre 2005Agn and Galaxy Evolution

Paolo Tozzi

AGN and Galaxy evolution from

Deep X-ray surveys: latest

results from the CDFS

Deep X-ray Surveys: open issues

The unresolved fraction of the XRB at high energies, and its relation with obscured cosmic matter accretion

The two epochs of cosmic accretion

X-ray properties of optically or radio selected sources: star formation at high z

Effects of Large Scale Structure on AGN activity

0.3-1 keV

1-3 keV

3-7 keV

Rosati et al. 2002

National Geographic, Dec 2002

AGN Contribution to the hard XRBBeppo SAX Vecchi et al. 1999ASCA2 Ishisaki et al. 1999ASCA1 Ueda et al. 1999HEAO1 Marshall et al. 1980

CDFS (1Ms): XRB(S> 4.5×10 -16) = (1.70±0.15)×10 -11 erg s -1cm -2deg -2

90% resolved in 0.5-2 keV

93% resolved in 2-8 keV

AGN contribution

83% in 0.5-2 keV

95% in 2-8 keV(Bauer et al. 2004)

CDFN (2Ms): XRB(S> 2 ×10 -16) = (2.07±0.15)×10 -11 erg s -1cm -2deg -2

Worsley et al. 2004; 2005Missing XRB: NH=4.5 1023 cm-2 @ z=0.8

~50% not resolved yet

for E> 5 keV(Worsley et al. 2004, 2005)

The unresolved fraction increases with the energy band

Compton thick candidates

NH vs redshifts for the whole sample

Detected fraction as a function of NH and z

Sampling different luminosities and spectral population at different z

z < 0.7

0.7 < z <1.5

z > 1.5

Tozzi et al. 2004

NH histogram corrected for completeness

The NH distribution

tells us about the fractionof the sky seen from theblack hole coveredby a given column density

Tozzi et al. 2005

NH distribution vs Optical Type

Whole sample (321)Cthick candidates (14)

Consistent with evolutionary sequence:pre-QSO phaseC-thin absorbed QSO (QSOII @ high z)unobscured QSO activityquiescent spheroidal galaxyAlexander et al. 2005; Stevens et al. 2005

Model: Granato et al. 2005

Part of the missing XRB is fromintermediate z strongly absorbedmoderate luminosity, possibly C-thick sources, in a secondary, relatively low-z phase of accretion(see “downsizing” or anti-hierarchical behaviour)

Whole sample (321)QSOII (44)

Ueda et al 2003Hasinger et al. 2005

Luminosity dependent density evolution:downsizing or anti-hierarchical behaviour

Merloni 2005

It is crucial to understand the properties of accretion through acareful analysis of the X-ray emission properties(luminosity, intrinsic absorption and its dependence on luminosity and redshift)

Compute the contribution of the absorbed sources to the XRB

Worsley et al. 2004This work

After computing the skycoverage according to the spectral shape of each source

Submm detection of a Type II QSOMainieri et al. 2004

As expected in the starburst/BH model (Fabian 1999)

Use secure spectral identifications in CDFS and CDFN

Norman et al. 2004

29 galaxies with good spectra in the CDFS and emission line ratios consistent with starbursts or normal galaxies give the X-ray priors. A Bayesian approach allows us to identify 74 galaxies in the CDFS and 136 in the CDFN (2 Ms)

SFR densities

Compilation from Tresse et al. 2002:

Gallego et al. 1995 (H )

Gronwall 1999

Hopkins et al. 2000

Pascual et al. 2001

Tresse et al. 2002

Sullivan et al. 2000

Lilly et al. 1996

Lines from 60 m

Saunders et al. 1990, Takeuchi et al. 2003

Norman et al. 2004

XLF consistent with a PLE ~ (1+z)2.7

Consistent with an evolution of SFR Q (1+z)2.7 for 0<z<1.

XLF of Star Forming Galaxies is a goal for future X-ray missions (Con-X, XEUS)

Daddi et al. 2004

K20 survey

IR selected galaxies at z~2 with massive SF

Daddi et al. 2004

Stacked image of 23 BzK galaxies; HR< -0.5 @ 2sigma ; L2-10

~1042 erg/secSFR ~ 170 MA yr-1 (4 higher than LBG). SFRD of 0.04 MA /yr/Mpc3

We are witnessing the massive spheroid formation epoch(the peak of just the low-z tail?)

Soft Hard

ExtendedCDFS

PI N. Brandt~1000 sources(Lehmer et al. 2005)

1Ms+

4 X 240 ks

Radio Catalog236 sourceson ~ the same ECDFS area

Match Radio Sources with

366+644 sources in the

1Ms+ECDFS(new only)

Combined X-ray images of

all the remaining

radio sources

With K. Kellerman, Ed Fomalont, J. Kelly, P. Shaver, & the CDFSTeam.

X-ray Radio matches:48 sources (out of 366 in the 1Msec catalog)83 sources (in the 1Ms+EXT cat)45 sources have:spectroscopic redshift and optical type (27)photometric redshift (18)soft and hard band luminosityIntrinsic absorption, spectral shape

160 Radio sources without X-ray counterpartBut with sub-treshold X-ray emission:83 within the 1Ms+ECDFS exposure+77 within the ECDFS (only 240 ks)

13 sources with LX<1042 erg s-1

8 LEX2 HEX3 non id

LR-L

X correlation

for sources with X-raydetection for 45 sourceswith z (luminosity from best fit X-ray model)(soft hard)

Distribution of intrinsic NH

Distribution of intrinsicabsorption for 45 sourceswith spec or photometric z, compared with the distribution of the whole X-ray sample

17 sources with high LR

28 sources with low LR

NH>1022 cm-2 ~ Type II AGN

1021 < NH < 1022 cm-2 ~ Type I AGN

NH<1021 cm-2 ~ Type I AGN – SF Gal

Photometry for the 83 sourceswithin the 1Ms fielddetected only in the radio:485 +- 80 soft (0.5-2 keV)260 +- 80 hard (2-7 keV)

X-ray photometry for the remaining Radio sources

Gilli et al. 2003

Large Scale structures in CDFS

AGN and Early Type galaxies

(from K20 survey, Cimatti et al.

2002) are tracing

the same structures.

Weak hints for enhanced X-ray

activity in large scale structures.

X-ray to K-band number ratio is

0.33±0.07 in the field

0.36±0.10 at z=0.73

0.7±10.22 z=0.67

Gilli et al. 2004

Γ = 1.33 ± 0.11

r0 = 8.6 ± 1.2 h-1 Mpc CDFS

r0 = 4.2 ± 0.4 h-1 Mpc CDFN

consistent with that of early type galaxies

Gilli et al. 2004

Prospects for the current X-ray surveys

Extended CDFS COSMOS XMM

2 deg2, 25 pointings, 60 ksec each

Hasinger et al. 2006

Other wide X-ray surveys: Bootes (9 deg2); ELAIS (1 deg2)

Lehmer et al. 2005

0.3 deg2, 4 pointings, 250 ksec each

COSMOS area

galaxy formation simulation :

gas red – yellow stars blue

credit : Takeda 4D2U/NOAJ -- Saitoh & Koda

Expected clustering significance

Credits to R. Gilli

CONCLUSIONS

Hard XRB resolved at 90 % level at fluxes S ~ 2×10-16 below 5 keV (but ~50% @5 keV: the energy density of the XRB peaks at 30 keV)

A hard, faint population still to be discovered (possibly Compton thick

sources detectable in submm with SCUBA/Spitzer)

Part of this “missing population can be already in the faintest part of the X-

ray sources population

Towards an universal distribution of intrinsic absorption

Evidence for strongly absorbed, C-thick sources @ z~1, and a substantial QSOII

population at z>~2

>~80% of the AGNs agree with simple unification models.

X-ray Emission from Normal Galaxies: SFR up to z~1; Star forming massive

galaxies at z~2 seen in X-ray

Mild effect of the Large Scale structures on nuclear activity, but larger efforts

under way

X-ray spectral analysis

Power law+

intrinsic absorption

+ Gaussian line @ 6.4 /(1+z) keV

+ scattered componentunabsorbed power law (same slope)

Galactic absorption

Synthesis Models for the Cosmic XRB (Setti & Woltjer 1989, Madau,

Ghisellini & Fabian 1994, Comastri et al. 1995, Gilli, Salvati &

Hasinger 2001)

were built on the following assumptions:

The Cosmic X-ray Background is largely due to accretion

onto supermassive black holes integrated over cosmic time.

The X-ray observations are consistent with a mixture of

absorbed and unabsorbed AGN, folded with the corresponding

luminosity function and cosmological evolution.

Most of the AGN spectra are heavily absorbed, and ~ 80% of

the light produced by accretion is absorbed by gas and dust

(in the nuclear starburst region that feeds the AGN).

Obscured fraction vs L

Tozzi et al. 2005

Ueda et al. 2003

ROSAT and ASCA resolved most of the Soft XRB. The spectral index of AGNs detected with ROSAT/ ASCA is Γ= 1.7 -2.0 steeper than the Hard XRB (Γ= 1.4). ASCA and SAX resolved ~ 30% of the hard XRB. The remaining ~ 70% is due to a population of absorbed sources seen with Chandra and XMM

The XRB is the echo of the formation of Massive Black Holes

through the history of the Universe

Compton Thick sources

Norman et al. 2002

QSOII6 x 1023 cm-2

if Compton thin

Evidence that the NIR light of QSOII is dominated by the host galaxy20% of EROS among X-ray selected AGN ~ 20-40% of the QSOII pop (Brusa et al. 2004)

Very Hard LogN -LogS (5 -10 keV)

CDFS 940 ks

XMM LH

(Hasinger et al. 2001)

Steep slope (~ Euclidean)

Hardest sources

missed by Chandra?

The population of absorbed sources is still increasing at low fluxes

How to detect these sources???

α = 1.35

R-K vs NH

BLAGNHEXLEXGAL

Szokoly et al. 2004

A mixed optical-X-ray classification

BLAGNHEXLEXABS

43% of X-ray detected AGN are classifiedas LEX+ABS

CDFS Spectral IDObject class z<2 z>2

AGN -1 26-5 5-0AGN -2 41-41 1-1QSO -1 12-0 5-2QSO -2 1-0 7-2Galaxy 28-5 0Clusters 5-1 0Star 7 0

Total 138-57

Szokoly et al. 2004Unsecure = 1 single line (OII, Ly)

Contribution from resolved sources below

S= 10 -15 erg s-1 cm-2 in the 1 -2 keV band is

6.25 10 -13 erg cm-2 s-1 deg-2 (14% of the ROSAT value).

A total of 83% of the ROSAT-XRB value is resolved.

After adding a 6% from bright Clusters, we have a strict

upper limit of 11% for the diffuse emission from warm

gas (the hidden WHIM).

Soft X -ray Background

X-ray galaxies detected in the infrared, high FhardX

/Fopt

colors consistent with reddened elliptical at z ~ 1-2

possibly heavily obscured AGN and/or LMXBsee also Crawford et al. 2001

Early Type Galaxies

Active SF Galaxies?Leitherer et al. 1995

Kennicutt 1992

For 9 emission line galaxies

in the Lynx field (180 ks with

Chandra) (Stern et al. 2001)

Buried AGN rather than OB and HMXB in “normal”

galaxies at high fluxes (XBONG).

SFR X= 2 -20 ×10 -40 L

2-10 M⊙yr-1

SFR X

= 10 3 ×SFROII

First results from Deep Chandra Surveys:

looking at galaxies at bright fluxes (2001)

Zheng et al. 2004

Photometric redshifts: check on spectroscopic redshiftsHyperz: NUV U V B V R I Z J H K

Comparing CDFS and

K20 surveys (Cimatti et al.

2002): clear large scale

structures are detected

as two narrow (dz<0.02)

spikes at

z = 0.67 (19 obj)

z = 0.73 (19 obj)

+

z=1.04 (6 obj)

z=1.22 (4 obj)

z=1.62 (5 obj)

z= 2.57 (4 obj)

Gilli et al. 2003

Gilli 2003

Tracing the accretion power is not straightforward even in X-ray (see Brandt et al. 2004)

25 ksec

118 ksec

303 ksec

174 ksec

333 ksec

392 ksec

515 ksec

645 ksec

740 ksec

808 ksec

939 ksec

0.5 -7 keVOCTOBER

1999

DECEMBER

2000Fsoft

= 5.5 × 10 -17 erg s -1 cm -2

Fhard

= 4.5 × 10 -16 erg s -1 cm -2

October 15, 1999

Szokoly et al. 2004

HEX

BLAGN

BLAGN

?

?

Szokoly et al. 2004

LEX

BLAGN

?

Zheng et al. 2004Mainieri et al. 2004

BPZ

F435w F606w F775w F850lp J H K (ISAAC)

Net detected counts in the 0.5-2 keV and 2-7 keV bands for the 366 sources in the CDFS

CDFS+CDFN XLF

Norman et al. 2004

CDFS spectroscopic galaxy sample with the 60 m warm LF, and spectral energy

distribution used for k-correction (hot gas from superwinds and X-ray binaries emission).

Better agreement with IR sample (maybe hint of some AGN contamination).

IR Bright Galaxies at z~2 with massive SFR

Daddi et al. 2004

Nine K-band luminous galaxies at 1.7 < z < 2.3, with SFR ~ 100-500 M⊙ /yr

(LX<1042 erg/s, stacked X-ray img gives 100 M⊙ /yr each, except one with

L2-10 ~3× 1042 erg/s, SFR~ 500M⊙/yr. Stellar masses M > 1011 M⊙ for most of them.

They contribute a SFR Density of 0.04 M⊙ /yr/Mpc

Therefore we are witnessing the massive spheroid formation epoch(the peak of just the low-z tail?)They already outnumber by more than 1 order of mag the predictions ofhierarchical models of galaxy formation (despite the spectral incompleteness)

VLT-ISAAC

ACS-F435W

ACS-F850LP

X-ray properties of Radio sources

To Do:Photometry of Radio-only sources in the new ECDFS sourcesSeparate pointlike sources from jets. Stacked spectra of X-ray non detections (1Ms and ECDFS)....

Science:Search for Radio emission from heavily obscured AGN (among the X-ray detected, not the missed ones as in Donley et al.)- Radio compactness vs N

H

Decoupling SF Galaxies from AGN? Distribution of AGN vs SF activity as a function of Radio flux for X-ray detected sources.X-ray non detected: SF high-z galaxies or strongly absorbed AGN? Average X-ray spectral properties of non-detections.....

Distribution of opticaltype among the 27 sources with good opticalspectroscopy(fluxes and luminosities)

Obscured fraction vs redshift

Ueda et al. 2003

Tozzi et al. 2005