Obscured and unobscured growth of Super-massive Black Holes Francisco J. Carrera, X. Barcons, J. Bussons, J. Ebrero, M. Ceballos, A. Corral (IFCA, CSIC-UC, Spain) & XMM-Newton Survey Science Centre (S. Mateos, M. J. Page, M.G. Watson, J. Tedds, R. Della Ceca...) Extragalactic X-ray Surveys, Boston, November 6, 2006

Resolving the X-ray background: An XMM-Newton International Survey (AXIS)

Definition of the AXIS survey ( Carrera et al 06 ) 36 XMM-Newton target fields: –Galactic latitude |b|>20 deg –X-ray observations with EPIC-pn detector in FULL-FRAME-MODE –~Avoided fields with bright and/or extended targets –Good time intervals > 10 ksec –Available early on in the mission Solid angle ~4.8 deg 2 Using SAS v6.1.1 to produce final source list and products: –Exposure and background maps –Source detection –Spectra and calibration matrices Areas around target + OOT+ near the pn CCD gaps excluded Own empirical sentitivity maps from detected source parameters Very detailed source screening Total of 1433 distinct X-ray sources with detection likelihood >15 in any of 4 bands (see below) NGC4291 Mrk 205

Soft keV XID keV Hard 2-10 keV Ultrahard keV X-ray source counts (XMM-Newton & Chandra & ASCA)

The contribution to the X-ray background Shallow MediumDeep Surveys Medium surveys resolve the brightest 50% of the X-ray background

The XMM-Newton Medium Survey (XMS)

The XMS samples ( Barcons et al. 07 ) NameBand (keV)Flux limit cgs # sources (unique) # identified (fraction) Soft XMS-S (1)200 (95%) Hard XMS-H (20)132 (83%) XID XMS-X (56)261 (92%) Ultrahard XMS-U (2)60 (86%) Subset of AXIS: –25 fields chosen for follow-up: 3.3 deg 2 –Flux limited in Soft, Hard and XID

Optical identification of the XMS Optical imaging: g,r,i (SDSS), Z (Gunn), mostly at the INT/WFC to r~23-24 mag Reliable & unique candidate counterpart in r/i for virtually all sources (< 5” or < 5  ) Optical spectroscopy –50% from AXIS programme (WHT, TNG, NOT): multi- fibre and long-slit spectroscopy –20% from Calar Alto/3.5m long-slit spectroscopy –15% from VLT/FORS2 long-slit spectroscopy –A few from AAT/2dF, SUBARU/FOCAS, and others Preliminary results from 2 XMM-Newton fields (~30 sources) in Barcons et al (2002)

The content of the XMS

4m spec lim 10m spec lim Deep MediumShallow

Breakdown of identified sources XMS-S Soft XMS-H Hard XMS-X XID XMS-U Ultrahard Broad-line AGN75% (148/200) 63% (83/132) 73% (190/261) 65% (39/60) Narrow-line galaxies (AGN) 13% (27/200) 27% (35/132) 15% (39/261) 27% (16/60) Absorption line galaxies+clust 4% (8/200) 7% (9/132) 4% (10/261) 5% (3/60) Stars8% (15/200) 2% (3/132) 8% (20/261) 0% (0/60)

Redshift distribution Soft Hard Peak of QSO distribution (z~1.5) well sampled. Obscured population out to z~1 in Hard sample

Luminosities and redshifts Soft Hard z=2.2 All galaxies consistent with hosting AGN L X >10 42 erg/s QSOs “Seyferts”

Tips for statistical identification ~90% Obscured AGN 90% unobscured AGN Stars HR2 log(F Hard /F opt )

Obscured and Unobscured AGN

X-ray to optical ratio: a marker for obscuration? Soft 5% of sources with f X /f opt >10 30% of fX/fopt>10 obscured AGN F X /F opt >10 Hard log(F Hard /F opt ) 15% of sources with f X /f opt >10 ~70% of fX/fopt>10 obscured AGN log(F Soft /F opt ) F X ( cgs)

Optical colours QSOs S+Irr E+S0 10% of QSOs are red QSOs S+Irr E+S0 HardSoft r-i g-r #

Reddening Fainter X-ray sources are redder? F Hard ( cgs) r-i

Optical versus X-ray “colours”: Hard Hard Softer Harder sources are >90% obscured AGN Softer sources: Optically blue: unabsorbed AGN Optically red: mix of abs & unabs AGN HR2 g-r

X-ray absorption vs obscuration: not equivalent The XMS survey 10% of type 1 AGN are absorbed (with N H <10 22 cm -2 ) >40% of type 2 AGN are absorbed Mateos et al (2005) The Lockman Hole survey 15% (<30% at 3  ) of type 1 AGN are absorbed (with N H <10 22 cm -2 ) 80% (>50% at 3  ) of type 2 AGN are absorbed. But 5/28 are unabsorbed Mateos et al (2006)

Stacking analysis

Procedure still being tested Selecting X-ray spectra with >80cts Unfolding with best fit Gal+Intrinsic abs. p.l. Correcting for Galactic N H De-redshifting Renormalizing using flux in 2-8 keV band Averaging in final bins (≥500 cts) Averaging AXIS: –BLAGN (200 sources) –NELG (43) Much improved averaging AXIS+XMM-2dF (see Xu, Mateos): –BLAGN (549):  =1.95±0.02 Fe keV EW=130±60 eV –NELG (113):  =1.53±0.02 Fe keV EW=130±100 eV AXIS+XMM-2dF BLAGN AXIS+XMM-2dF NELGs Averaging X-ray spectra Corral et al., in preparation

Conclusions

On-going work Brightest 50% of the X-ray background dominated by AGN. Unobscured accretion dominates, but increasingly important contribution from obscured objects. X-ray absorption and optical obscuration not equivalent: –10% of type 1 AGN are X-ray absorbed –15% of type 2 AGN are not X-ray absorbed –25% of f X /f opt >10 hard X-ray sources are type 1 AGN –10% of X-ray selected type 1 AGN have red colours Even at medium fluxes, an important fraction of the X-ray sources have optically faint and red optical counterparts. Most unIDed objects faint (r/i>21.5) and extended: NELGs Preliminary results from average spectra show Fe lines in both BLAGN and NELGs