Obscured and unobscured growth of Super-massive Black Holes

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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
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Resolving the X-ray backgroundAn XMM-Newton
International Survey (AXIS)
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Definition of the AXIS survey (Carrera et al 06)
Mrk 205

• 36 XMM-Newton target fields
• Galactic latitude bgt20 deg
• X-ray observations with EPIC-pn detector in
  FULL-FRAME-MODE
• Avoided fields with bright and/or extended
  targets
• Good time intervals gt 10 ksec
• Available early on in the mission
• Solid angle 4.8 deg2
• 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 gt15 in any of 4 bands (see
  below)

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X-ray source counts (XMM-Newton Chandra ASCA)
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The contribution to the X-ray background
Surveys
Medium surveys resolve the brightest 50 of
the X-ray background
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The XMM-Newton Medium Survey(XMS)
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The XMS samples (Barcons et al. 07)

• Subset of AXIS
• 25 fields chosen for follow-up 3.3 deg2
• Flux limited in Soft, Hard and XID

Name Band (keV) Flux limit 10-14 cgs sources (unique) identified (fraction)
Soft XMS-S 0.5-2 1.5 210 (1) 200 (95)
Hard XMS-H 2-10 3.3 159 (20) 132 (83)
XID XMS-X 0.5-4.5 2.0 284 (56) 261 (92)
Ultrahard XMS-U 4.5-7.5 - 70 (2) 60 (86)
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Optical identification of the XMS

• Optical imaging g,r,i (SDSS), Z (Gunn), mostly
  at the INT/WFC to r23-24mag
• Reliable unique candidate counterpart in r/i
  for virtually all sources (lt 5 or lt 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)

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The content of the XMS
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Deep
Medium
Shallow
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Breakdown of identified sources
XMS-S Soft XMS-H Hard XMS-X XID XMS-U Ultrahard
Broad-line AGN 75 (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 galaxiesclust 4 (8/200) 7 (9/132) 4 (10/261) 5 (3/60)
Stars 8 (15/200) 2 (3/132) 8 (20/261) 0 (0/60)
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Redshift distribution
Obscured population out to z1 in Hard sample
Soft
Peak of QSO distribution (z1.5) well sampled.
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Luminosities and redshifts
Soft
QSOs
Hard
Seyferts
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Tips for statistical identification
90 unobscured AGN
log(FHard/Fopt)
90 Obscured AGN
Stars
HR2
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Obscured and Unobscured AGN
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X-ray to optical ratio a marker for obscuration?
log(FSoft/Fopt)

• 5 of sources with fX/foptgt10
• 30 of fX/foptgt10 obscured AGN

Soft
FX(10-14cgs)
log(FHard/Fopt)

• 15 of sources with fX/foptgt10
• 70 of fX/foptgt10 obscured AGN

Hard
FX(10-14cgs)
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Optical colours
r-i
g-r
g-r
Hard
Soft

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Reddening
Fainter X-ray sources are redder?
r-i
FHard(10-14cgs)
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Optical versus X-ray colours Hard
Harder sources are gt90 obscured AGN Softer
sources Optically blue unabsorbed AGN
Optically red mix of abs unabs AGN
g-r
Hard
HR2
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X-ray absorption vs obscuration not equivalent

• The XMS survey
• 10 of type 1 AGN are absorbed
• (with NHlt1022 cm-2)
• gt40 of type 2 AGN are absorbed

• The Lockman Hole survey
• 15 (lt30 at 3?) of type 1 AGN
• are absorbed (with NHlt1022 cm-2)
• 80 (gt50 at 3?) of type 2 AGN
• are absorbed. But 5/28 are unabsorbed

Mateos et al (2006)
Mateos et al (2005)
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Stacking analysis
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Averaging X-ray spectraCorral et al., in
preparation

• Procedure still being tested
• Selecting X-ray spectra with gt80cts
• Unfolding with best fit GalIntrinsic abs. p.l.
• Correcting for Galactic NH
• 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 AXISXMM-2dF (see Xu,
  Mateos)
• BLAGN (549) ?1.950.02 Fe line _at_6.50.2 keV
  EW13060 eV
• NELG (113) ?1.530.02 Fe line _at_6.60.4 keV
  EW130100 eV

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Conclusions
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• 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 fX/foptgt10 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/igt21.5) and
  extended NELGs
• Preliminary results from average spectra show Fe
  lines in both BLAGN and NELGs