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