X-ray spectroscopy of bright Seyfert 2s:

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X-ray spectroscopy of bright Seyfert 2s The
importance of the 10-100 keV spectrum
Guido Risaliti
INAF - Arcetri Observatory, Italy Harvard-Smiths
onian Center for Astrophysics
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NGC 1365 The best laboratory to investigate the
absorber in obscured AGN
Hard X-ray observations
ASCA (1995) 40 ks BeppoSAX (1997)
30 ks Chandra (Dec 2002) 15 ks XMM 1 (Jan 2003)
17 ks XMM 2 (Jan 2003) 10 ks XMM 3 (Aug 2003)
15 ks XMM 4 (Jan 2004) 60 ks XMM 5 (Aug 2004)
60 ks
Chandra (Apr 2006) 6 x 15 ks
(Risaliti et al. 2007, ApJ 659, L11)
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NGC 1365 Two XMM long observations
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Spectral analysis of XMM long observations
2. Relativistic Iron Line

• One of the best cases, only (?) strong case in
  high NH sources
• Disappearing in obscured spectrum --gt within 1014
  from the center

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Intra-day NH variations
XMM 4 60 ks
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Short-time column density variability

• New analysis
• 10 time intervals, 6 ks each
• Constant continuum (a) free NH for each
  spectrum
• (b) two
  NH (the same for all spectra)
• 
  and free covering factor of NH2

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Only) other know case NGC 4151 observation with
BeppoSAX
Puccetti et al. 2007
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Simbol-X simulations
T 6 ksec NH2x1023 cm-2
E(NH) 6
XMM (var. cont.)
E(NH) 20
XMM (const cont.)
E(NH) 6
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Conclusions

• - Short timescale (5-10 ksec) column denisty
  variability may
• be common in Seyfert Galaxies
• Resolving the NH variability is crucial to
  understand the
• structure of the circumnuclear absorber AND
• to obtain a correct fit of the other spectral
  components
• High quality 10-50 keV spectra needed to
  unambigously
• detect NH variability
• Simbol-X capable to completely remove degeneracy
  between
• spectral parameters in bright Seyfert Galaxies