Average Fe Ka emission from distant AGN

1
Average Fe Ka emission from distant AGN

• Amalia Corral
• IFCA(Santander)/OAB(Milano)
• M.J. Page MSSL (UCL), UK
• F.J. Carrera, X. Barcons, J. Ebrero IFCA
  (CSIC-UC), Spain
• S. Mateos, J.A. Tedds, M.G. Watson University of
  Leicester, UK
• A. Schwope, M. Krumpe Astrophysikalisches
  Institut Postdam, Germany

X-ray Universe 2008, Granada, 27th May 2008
2
Introduction

• XRB (X-Ray Background) is known to be composed of
  discrete sources, most of them are AGN.
• XRB synthesis models, ingredients
• - AGN intrinsic column density and acretion
  rate distribution and their evolution as a
  function of Luminosity and redshift.
• - Average radiative efficiency of accretion
  onto Supermassive Black Holes -gt Measure from Fe
  line relativistic profile.

3
Previous Results

• Local samples
• EW(relativistic) 100-200 eV (Guainazzi06,
  Nandra07)
• Distant AGN -gt average or stack many spectra
  together
• EW(relativistic) 400 (type1) - 600(type2) eV
• (Streblyanska05,Brusa05)

4
Our sample

• AGN from the AXIS (An International XMM-Newton
  Survey) and XWAS (XMM-Newton Wide Angle Survey)
  medium surveys (average flux 5x10-14 erg cm-2
  s-1) .
• Optical spectroscopic identifications (gt80 counts
  0.2-12 keV)
• Type 1 AGN 606 sources
• Type 2 AGN 117 sources

5
Our sample

• Sample selection
• Individual spectra gt 80 counts in 0.2-12 keV

6
Averaging method

• Fit an absorbed power law above 1 keV rest-frame
  and unfold the un-grouped spectra best-fit
  model.
• Correct for Galactic Absorption.
• Shift to rest-frame.
• Normalize using the 2-5 keV rest-frame band.
• Rebin to 1000 final counts/bin.
• Average.

7
Results
Type 1 AGN gt 200000 counts
Type 2 AGN 30000 counts
Fit simple power law in 2-10 keV Type 1
G1.920.02 Type 2
G1.440.02
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Results
Type 1 AGN gt 200000 counts
Type 2 AGN 30000 counts
Broad relativistic profile not clearly present
9
Simulations

• 100 simulations (best-fit model) per real
  spectrum including Poisson counting noise and
  keeping the same 2-8 keV observed flux, exposure
  time and calibration matrices as for the real
  data.
• Significance contours by removing the 32 (1s
  level) and 5 (2s level) extreme values.

10
Results
11
Results
12
Spectral fit

• Baseline model
• 100-simulations continuum mixture of absorbed
  power laws.
• Narrow emission line.

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Spectral fit Type 1 AGN

• Best-fit model Baseline model plus neutral
  reflection
• Egaus 6.360.05 keV
• sgaus 8080 eV
• EWgaus 9030 eV
• i 6020º
• R0.50.20

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Spectral fit Type 1 AGN

• Best-fit model Baseline model plus neutral
  reflection
• Egaus 6.360.05 keV
• sgaus 8080 eV
• EWgaus 9030 eV
• i 6020º
• R0.50.20

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Spectral fit Type 1 AGN

• Best-fit model Baseline model plus neutral
  reflection
• Egaus 6.360.05 keV
• sgaus 8080 eV
• EWgaus 9030 eV
• i 6020º
• R0.50.20

EW(broad relativistic line) lt 400 eV at 3s
confidence level
16
Spectral fit Type 2 AGN

• Model Baseline model plus neutral reflection
• Egaus 6.360.07 keV
• sgaus 8060 eV
• EWgaus 7030 eV
• i lt 80
• R gt 0.7

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Spectral fit Type 2 AGN

• Model Baseline model plus neutral reflection
• Egaus 6.360.07 keV
• sgaus 8060 eV
• EWgaus 7030 eV
• i lt 80
• R gt 0.7

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Spectral fit Type 2 AGN

• Model Baseline model plus Laor line
• Egaus 6.360.07 keV
• Elaor 6.7 keV
• sgaus 8060 eV
• EWgaus 7040 eV
• EWlaor 300 eV
• i 60º

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Spectral fit Type 2 AGN

• Model Baseline model plus Laor line
• Egaus 6.360.07 keV
• Elaor 6.7 keV
• sgaus 8060 eV
• EWgaus 7040 eV
• EWlaor 300 eV
• i 60º

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Spectral fit Type 2 AGN

• Model Baseline model plus Laor line
• Egaus 6.360.07 keV
• Elaor 6.7 keV
• sgaus 8060 eV
• EWgaus 7040 eV
• EWlaor 300 eV
• i 60º

Neutral reflection and Relativistic line give the
same fit
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Type 1 AGN sub-samples

• Number of counts 2-10 keV gt 2x105 allow us to
  test evolution with different parameters by
  dividing the sample in 3 subsamples of equal
  quality (i.e. number of total counts) redshift,
  flux and luminosity.
• We found no dependence for the emission features
  on redshift or flux.
• Dependence on Luminosity -gt Iwasawa- Taniguchi
  effect?

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Type 1 AGN sub-samples
L(0.5-2 keV) (erg s-1) EW narrow line (eV)
1x1042 2x1044 19050
2x1044 6x1044 15080
6x1044 6x1046 5040
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Conclusions

• Narrow emission line significatively detected in
  Type 1 and Type 2 AGN average spectra. E 6.4
  keV, EW 100 eV.
• Type 1 AGN No compelling evidence of a Broad
  component in the average spectrum. Continuum
  features best represented by a reflection
  component. Relativistic line upper limit EWlt400
  eV (3s confidence).
• Iwasawa-Taniguchi effect for narrow line
  component marginally detected.
• Type 2 AGN Statistics insufficient to
  distinguish between a relativistic line and a
  reflection component.

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Conclusions

• Narrow emission line significatively detected in
  Type 1 and Type 2 AGN average spectra. E 6.4
  keV, EW 100 eV.
• Type 1 AGN No compelling evidence of a Broad
  component in the average spectrum. Continuum
  features best represented by a reflection
  component. Relativistic line upper limit EWlt400
  eV (3s confidence).
• Iwasawa-Taniguchi effect for narrow line
  component marginally detected.
• Type 2 AGN Statistics insufficient to
  distinguish between a relativistic line and a
  reflection component.

25
Conclusions

• Narrow emission line significatively detected in
  Type 1 and Type 2 AGN average spectra. E 6.4
  keV, EW 100 eV.
• Type 1 AGN No compelling evidence of a broad
  component in the average spectrum. Continuum
  features best represented by a reflection
  component. Relativistic line upper limit EWlt400
  eV (3s confidence).
• Iwasawa-Taniguchi effect for narrow line
  component marginally detected.
• Type 2 AGN Statistics insufficient to
  distinguish between a relativistic line and a
  reflection component.

26
Conclusions

• Narrow emission line significatively detected in
  Type 1 and Type 2 AGN average spectra. E 6.4
  keV, EW 90 eV.
• Type 1 AGN No compelling evidence of a broad
  component in the average spectrum. Continuum
  features best represented by a reflection
  component. Relativistic line upper limit EWlt400
  eV (3s confidence).
• Iwasawa-Taniguchi effect for narrow line
  component marginally detected.
• Type 2 AGN Statistics insufficient to
  distinguish between a relativistic line and a
  reflection component.

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THANK YOU