on behalf of the xmm-newton survey science centre roberto della ceca inaf – osservatorio...
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On behalf of the
XMM-Newton Survey Science Centre
Roberto Della CecaINAF – Osservatorio Astronomico di
Brera,Milan
The Cosmological properties
of AGN in the XMM-Newton Hard Bright
Survey
Co-authors
A. Caccianiga (INAF –OABrera, Milan, Italy) P. Severgnini (INAF –OABrera, Milan, Italy)T. Maccacaro (INAF –OABrera, Milan, Italy)H. Brunner (Max Planck, Garching,
Germany) F.J. Carrera (IFCA, Santander, Spain)F. Cocchia (INAF-OARoma, Italy)S. Mateos (Leicester University, UK)M.J. Page (MSSL, UK)J.A. Tedds (Leicester University, UK)
Why hard X-ray surveys are important
Most direct probe of the SMBH accretion activity
SMBH census
Constraints to models for the formation and evolution of structures in the Universe
A few key questions….
Which are the cosmological properties (e.g. XLF) of the absorbed and unabsorbed AGN population?
Is the ratio absorbed/unabsorbed AGN a function of Lx and/or z?
How the results compare with the Unification models of AGN?
What about the heavily absorbed (NH>1024 cm-2) Compton Thick AGN?
The XMM Bright Survey is aimed at selecting and spectroscopically identifying a large and statistically representative sample of bright
(fx>~7x10-14 c.g.s) serendipitous XMM
sources in two complementary energy bands.
0.5-4.5 keV energy band: Bright Sample (BS) 4.5-7.5 keV energy band: Hard Bright Sample (HBSS)
The XMM-Newton Bright SurveyThe XMM-Newton Bright Survey
XMM fields used 237 Sources 400 (fx > ~7x10-14 cgs) Identified 348 (87%) (~240 sources from us)
Covered Area (deg2) 28 Spectroscopic Classification % Type 1 AGN 70% Type 2 AGN 10% Other Extragalactic 4% Stars 16%
The XMM-Newton Bright Survey in The XMM-Newton Bright Survey in pillspills
Optical and X-ray spectral analysis is possible for almost all the sources in the XBS!!
Della Ceca et al., 2004Caccianiga et al., 2008
The X-ray sky above 5 keV: the HBSS sampleThe X-ray sky above 5 keV: the HBSS sample
Intrinsic NH vs.
Intrinsic Lx
67 X-ray src65 with ID
Spectroscopic ID 97%
40 Unabsorbed AGN 22 Absorbed AGN
Int r
insic
NH
NH =4x1021
Intrinsic Luminosity
NH =4x1021 Av~2
Lx-z planeHBSS Sample
Unabsorbed AGN : 40 obj. Absorbed AGN : 22 obj.
<Log Lx> = 44.2<Log Lx> = 43.7
Redshift Distribution
Luminosity Distribution
Absorbed AGNvs.
Unabsorbed AGN
De-evolved (z=0) X-ray luminosity De-evolved (z=0) X-ray luminosity functionsfunctions
40 obj
22 obj
4x1021<NH<1024
NH<4x1021
Absorb
ed AGN h
ave a
ste
eper
XLF
than
the u
nabso
rbed o
nes1/Vmax method
(Schmidt, 1968),
correcting for the bias due
to the photoelectric absorption.
Fraction of absorbed AGN in the HBS Fraction of absorbed AGN in the HBS surveysurvey
Ab
sorb
ed
AG
N/A
ll A
GN
(N
H<
10
24 c
m-2)
HBSS
Beckman et al., 2006Bassani et al., 2006Markwardt et al., 2006Sazonov et al., 2007
Fraction = 0.570.11
Abs.AGN (4x1021<NH<1024 cm-2)----------------------------All AGN (NH<1024 cm-2)
Lx>3x1042 erg s-1
Fraction of absorbed AGN in the HBS Fraction of absorbed AGN in the HBS surveysurvey
Ab
sorb
ed
AG
N/A
ll A
GN
(N
H<
10
24 c
m-2)
HBSS
Beckman et al., 2006Bassani et al., 2006Markwardt et al., 2006Sazonov et al., 2007
From Integral/Swift• E> 10 keV
• fx>10-11 cgs
Lx>3x1042 erg s-1
Abs.AGN (4x1021<NH<1024 cm-2)----------------------------All AGN (NH<1024 cm-2)
Very
good a
greem
ent
Fraction of absorbed AGN vs. Intrinsic LxFraction of absorbed AGN vs. Intrinsic Lx
From the HBSS sample (z=0)using the best fit XLF
In agreement with e.g.: Ueda et al., 2003 La Franca et al., 2005Akylas et al., 2006Ballantyne et al., 2006
The frac
tion o
f obsc
ured A
GN
decreas
e with
L x
First pointed out by Lawrence and Elvis,1982
From the HBSS sample (z=0)
From Akylas et al., 2006
Fraction of absorbed AGN vs. Intrinsic LxFraction of absorbed AGN vs. Intrinsic Lx
<z>~0.8
<z>~1.2<z>~1.3
<z>~1.5
<z>~2.4
Redshift dependence?
From the HBSS sample (z=0)
Rescaled to z=0 using:~(1+z)0.4 from (Treister and Urry, 2006, Ballantyne et al., 2006)
Fraction of obscured AGN vs. Intrinsic LxFraction of obscured AGN vs. Intrinsic Lx
The frac
tion o
f obsc
ured A
GN
probab
ly in
creas
e with
z
See also La Franca et al., 2005
Comparison with Unification Comparison with Unification modelsmodels
The sim
plest
unifi
catio
n
schem
e of A
GN is ru
led o
ut
HBSS
Comparison with Unification Comparison with Unification modelsmodels
Standard receding torus modelLawrence (1991)
h
rtorustorus
AGN
h
r
torustorus
AGN
Comparison with Unification Comparison with Unification modelsmodels
Modified receding torus modelh L with =0.23
Simpson (2005); Honig and Beckert (2007)
Comparison with optical Comparison with optical samplessamples
HBSS
Fraction of optically Narrow line AGN Simpson (2005)
Compton ThinAND
Compton Thick
Only Compton Thin AGN
24214 EEThick NCN
)1(
)(
optx
xopt
FF
FFC
The intrinsic XLF of Compton Thick The intrinsic XLF of Compton Thick AGNAGN
The intrinsic XLF of Compton Thick The intrinsic XLF of Compton Thick AGNAGN
XLFThick = 2 x XLF4E21-E24
The intrinsic XLF of Compton Thick The intrinsic XLF of Compton Thick AGNAGN
XLFThick = 4 x XLF4E21-E24
XLFThick = XLF4E21-E24
The intrinsic XLF of Compton Thick The intrinsic XLF of Compton Thick AGNAGN
Thick AGN from Sazonov et al., (2007)INTEGRAL 17-60 keV Sample
ID rate = 93%; 4 CT AGN
Independent measurements
The intrinsic XLF of Compton Thick The intrinsic XLF of Compton Thick AGNAGN
Thick AGN from Daddi et al. (2007)
rescaled to z=0(Spitzer+Chandra) data
Independent measurements
The intrinsic XLF of Compton Thick The intrinsic XLF of Compton Thick AGNAGN
Thick AGN from Fiore et al. (2008)rescaled to z=0
(Spitzer+Chandra) dataONE OF THE NEXT TALKS
Independent measurements
The intrinsic XLF of Compton Thick The intrinsic XLF of Compton Thick AGNAGN
Very g
ood agre
ement w
ith
independent X
-ray-
infr
ared
sam
ples
of CT A
GN
Compton Thin AGN vs. Compton Thick Compton Thin AGN vs. Compton Thick AGNAGN
Compton Thick AGN NH>1024 cm-
2
----------------------------------------
Compton Thick AGN NH<1024 cm-
2
1.080.44
0.570.22
0.230.15The fr
actio
n of C
T AGN
decreas
e with
L x
ConclusionsWe have discussed here the HBSS AGN
sample. Absorbed AGN have a steeper XLF than the unabsorbed ones;
The intrinsic fraction of absorbed (Thin) AGN with Lx>~3x1042 cgs is 0.570.11. In excellent agreement with local samples of hard (>10 keV) selected AGN at a flux limit of 10-11 cgs; The fraction of abs. AGN is a function of Lx and, probably, of z;
Our results support the modified receding torus model;
We have derived, in an indirect way, the XLF of Compton Thick AGN and found that XLFThick ~ 2 x XLF4E21-E24;
The fraction Thick AGN/Thin AGN decreases with Lx.
The projects presented here have received partial financial support
from ASI, MIUR and INAF grants over the last few years.
THANKS
Astro-ph/0805.1919