Title: Statistical analysis of the X-ray emission properties of type-1 AGN in the XMM-2dF Wide Angle Survey
1Statistical analysis of the X-ray emission
properties of type-1 AGN in the XMM-2dF Wide
Angle Survey
- Silvia Mateos
- Leicester University (UK)
-
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- M.G. Watson, J. A. Tedds and Y. Xu Leicester
University (UK) - M. Page Mullard Space Science Laboratory-UCL
(UK) - F.J. Carrera and A. Corral Instituto de Física de
Cantabria CSIC-UC (Spain) - A. Schwope and M. Krumpe Astrophysikalisches
Institut Potsdam (Germany)
2- Motivation
- The sample of type-1 AGN in XMM-2dF Wide Angle
Survey is one of the largest samples of X-ray
selected type-1 AGN assembled so far - Unique resource to characterise the X-ray
emission properties of the dominant population of
sources at fluxes 10-14 erg cm-2 s-1, where the
bulk of the Cosmic X-ray Background (CXRB)
emission originates - Broad band continuum shape and intrinsic
dispersion - Fraction of X-ray absorbed type-1 AGN and
distribution of absorbing column densities -
- Dependence of emission properties on the X-ray
luminosity of the objects and redshift
3- XMM-2dF Wide Angle Survey
- 2dF optical multi-fibre spectroscopy on the AAT
obtained for 68 XMM-Newton fields (texp few
tens of ksec) over a total area gt15 deg2 - More than 3000 sources with X-ray fluxes above
10-14 cgs and optical counterparts brighter than
V21 observed and reduced - 978 serendipitous X-ray sources with
- 0.5-4.5 keV flux gt10-14 erg cm-2 s-1
spectroscopically identified
Type Number
BLAGN 641 (65.5)
NELG 157 (16)
Gal 57 (5.8)
Stars 123 (12.6)
4- Type-1 AGN in the XMM-2dF Wide Angle Survey
496 type-1 AGN with 75 EPIC counts selected for
X-ray spectral analysis
2-10 keV flux
Typical fluxes break in the X-ray source counts
5- X-ray spectral analysis
- Power law and absorbed power law (both absorbed
by the Galaxy) models fitted to all 0.2-12 keV
X-ray spectra - Single-source analysis of brightest objects (down
to 200 EPIC counts, 300 objects) now completed - F-test significance 95 to accept additional
spectral components -
-
- Overal results of spectral fits
- 381 (77) best fitted with a power law
- 37 (7.5) objects with detected
absorption - 78 (15.7) objects with detected soft
excess emission -
6Broad band continuum shape(I)
The 0.2-12 keV X-ray spectra type-1 AGN best
fitted with a power law of ?1.9. However
significant intrinsic dispersion in measured
values detected
?1.95 0.04 ?0.20 0.03
7Broad band continuum shape(II)
No clear cosmic evolution of the mean continuum
shape of type-1 AGN up to z3
8Broad band continuum shape(III)
2-10 keV lum
The 0.2-12 keV continuum shape does not show
obvious dependence with X-ray luminosity from
1043-1045 erg s-1
9Excess absorption in type-1 AGN(I)
X-ray absorption detected (F-test95) in 37
type-1 AGN (7)
No correlation between ? and NH
Typical values of absorbing column density NH
few 1021cm-2 For sources with NHgt1022 cm-2
existing correlation of optical and X-ray
emission properties unclear
10Excess absorption in type-1 AGN(II)
Detection of X-ray absorption in type-1AGN does
not occur at any preferred X-ray luminosity or
redshift
ltL2-10gt 44.17 unabsorbed type-1 AGN ltL2-10gt
44.25 absorbed type-1 AGN
11Excess absorption in type-1 AGN(III)
No evident dependence of X-ray absorbing column
densities detected in type-1 AGN with luminosity
or redshift
12- Conclusions
- 0.2-12 keV emission of most type-1 AGN best
fitted with a power law - mean continuum shape 1.95
- intrinsic dispersion 0.20
- Continuum shape
- no significant evolution up to redshifts of 3
- no luminosity dependence in range 1043-1045erg
s-1 - X-ray absorption detected in 7 of our type-1
AGN - absorbed type-1 AGN do not seem to occur
preferentially at - any particular redshift or luminosity
- no obvious dependence of NH with redshift or
luminosity - typical values 1021 cm-2 a substantial
fraction with detected - NHgt1022 cm-2
- Existing correlation of optical and X-ray
properties unclear -
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16Broad band continuum shape(IV)
2-10 keV flux
0.5-2 keV flux
The hardening of ? with X-ray flux known to be
mostly due to undetected X-ray absorption