X-ray emission properties of BLAGN in the XMM-2dF Wide Angle Survey

1. X-ray emission properties of BLAGN in the XMM-2dF Wide Angle Survey S. Mateos, M.G. Watson, J. A. Tedds and the XMM-Newton Survey Science Centre Department of Physics and Astronomy, University of Leicester

2. Motivation • Wide field surveys are essential to compile large enough samples • of objects at 2-10 keV fluxes ~10-15-10-14 cgs to characterise the dominant population contributing to the Cosmic X-ray Background (CXRB) • The sample of BLAGN in XMM-2dF Wide Angle Survey is one of the largest samples of X- ray selected BLAGN assembled so far • Unique resource to study the overall optical and X-ray emission properties of the population of faint Active Galactic Nuclei (AGN) • Continuum shape, soft excess and X-ray absorption properties • Constrain the fraction of X-ray absorbed BLAGN and the distribution of column densities • Cosmic evolution of the emission properties and dependence with X-ray luminosity

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 an area of >15deg2 • More than 3000 sources with X-ray fluxes above ~10-14 cgs and optical counterparts brighter than V~21 observed and reduced. 978 serendipitous X-ray sources with S (0.5-4.5 keV)>10-14 erg cm-2 s-1 spectroscopically identified: 641 BLAGN (65.5%) 157 NELG (16%) 57 Gal (5.8%) 123 Stars (12.6%)

4. BLAGN in the XMM-2dF Wide Angle Survey • All 119 XMM-Newton observations with overlap on the original area covered by the 2dF observations reprocessed using the latest pipeline of the second XMM-Newton Serendipitous Source Catalogue 2XMM (pre-release: 2XMMp available at http://xmmssc-www.star.le.ac.uk) 2-10 keV flux Typical fluxes~break in the X-ray source counts

5. X-ray spectral analysis • Co-added MOS and pn spectra obtained for each object • Selected 496 from 641 BLAGN with XMM-Newton X-ray spectra of sufficient quality for detailed X-ray spectral analysis • Simple power law and absorbed power law model fits • Single-source analysis of brightest objects to constrain the presence and properties of additional spectral components (such as soft excess) in progress >70% objects with more than 150 EPIC net cts

6. BLAGN overall emission properties: broad band continuum shape Most BLAGN spectra from 0.2-12 keV (observer frame) best fitted with a power law although significant intrinsic dispersion in measured values detected =1.96 ± 0.05 =0.22 ± 0.03

7. BLAGN overall emission properties: broad band continuum shape No clear trend with redshift up to z~4 The apparent hardening of  at higher z produced by undetected soft excess emission at lower z

8. BLAGN overall emission properties: broad band continuum shape 2-10 keV lum Continuum shape does not show obvious dependence with X-ray luminosity

9. BLAGN overall emission properties: intrinsic X-ray absorption X-ray absorption detected (F-test≥95%) in 38 BLAGN (~8%) BLAGN at z=0.132 =1.55 ± 0.2 NH=22.2 ± 0.3 cm-2 log (L2-10)=43.53 cgs kT=0.20 ± 0.04 keV

10. BLAGN overall emission properties: broad band continuum shape Best fit  values 0.5-2 keV flux 2-10 keV flux The hardening of  with X-ray flux known to be mostly due to undetected X-ray absorption

11. BLAGN overall emission properties: intrinsic X-ray absorption No correlation between  and NH Typical values of absorbing column density NH~1021cm-2 For sources with NH>1022 cm-2 existing correlation of optical and X-ray emission properties unclear

12. BLAGN overall emission properties: intrinsic X-ray absorption Fraction of absorbed BLAGN does not depend on X-ray luminosity or redshift <L2-10> = 44.2 unabsorbed BLAGN <L2-10> = 44.3 absorbed BLAGN

13. BLAGN overall emission properties: intrinsic X-ray absorption No evident dependence of absorbing column density with luminosity or redshift

14. Conclusions • 0.2-12 keV emission of most BLAGN is best fitted with a power law • mean continuum shape ~1.96 • intrinsic dispersion ~0.22 • Continuum shape • no significant evolution up to redshifts of ~4 • no luminosity dependence in range 1042-1045erg s-1 • Absorbed BLAGN do not seem to occur preferentially at any particular redshift or luminosity • X-ray absorption detected in ~8% of our BLAGN • observed hardening of mean continuum shape with 0.5-2 keV flux • suggests that X-ray absorption is still undetected in a number of • objects in our sample • no obvious dependence with redshift or luminosity • typical values ~1021 cm-2 –a substantial fraction with detected • NH>1022 cm-2 • Existing correlation of optical and X-ray properties unclear

15. XMM-2dF Wide Angle Survey Leicester University (UK) Mullard Space Science Laboratory-UCL (UK) Instituto de Física de Cantabria CSIC-UC (Spain) Astrophysikalisches Institut Potsdam (Germany) on behalf of the XMM-Newton Survey Science Centre http://xmmssc-www.star.le.ac.uk

18. Conclusions(I) • The 0.2-12 keV emission of most BLAGN is best fitted with a power law with mean continuum shape of ~1.96 although with a significant intrinsic dispersion of ~0.22 around the mean measured value • The overal X-ray emission properties (continuum • shape and X-ray absorption) of our BLAGN do not • seem to show any significant evolution up to redshifts • of ~4 or luminosity dependence within the luminosity • range 1042-1045erg s-1 • X-ray absorption was detected in ~8% of our BLAGN, although the observed hardening of the mean continuum shape with 0.5-2 keV flux suggests that X-ray absorption is still undetected in a number of objects in our sample

19. Conclusions(II) • The observed absorption column densities in our sample of BLAGN have typical values ~1021 cm-2, whithout obvious dependence with redshift or luminosity • Absorbed BLAGN do not seem to occur preferentially at any particular redshift or luminosity