1. The X-ray Universe 2008 - Granada
Accretion and reflection
in Galactic BHs and AGNs
Giovanni Miniutti
Lab. Astroparticule et Cosmologie - Paris
The X-ray Universe Granada

2. Accreting black holes: the X-ray view
Soft excess
Power law
X-ray reflection
e.g. Fabian & Miniutti 07 (CUP review)
all modified by absorption (Galactic and/or local)

3. The X-ray reflection spectrum
PLC
RDC
Reynolds 96

4. The X-ray reflection spectrum
this is the X-ray reflection
spectrum in the rest frame of
the emitting gas
however, if emission comes from the accretion disc one has
to consider:
the strong gravity of the BH
the fast orbital motion close to the center

5. X-ray reflection: relativistic effects
Doppler shifts
Fe K
relativistic beaming
gravitational redshift
intensity
gravitational light bending
energy

6. X-ray reflection: relativistic effects
ISCO vs spin
Kerr/Schwarzschild

7. X-ray reflection: relativistic effects
rest frame spectrum
observed spectrum

8. The broad Fe line of MCG-6-30-15
Fabian et al 02; Vaughan & Fabian 04
Tanaka et al 95

9. The broad Fe line of MCG-6-30-15
Suzaku
Miniutti et al 07

10. The broad Fe line of MCG-6-30-15
The broad Fe line first detected by ASCA was later confirmed by all subsequent X-ray missions
The latest observation was performed with the Suzaku observatory
Fe xxv Fe xxvi
Suzaku
XMM
Miniutti et al 07
Fe xxv Fe xxvi
Suzaku

11. Other possible interpretation ?
Spectral curvature in the Fe K band + excess above 10 keV can also be reproduced with (rather complex) absorption models:
3 different emission components +
5 different absorption zones: only 2 are global ( and gratings-detected)
Miller et al 08

12. Other possible interpretation ?
The claim is that with this model one can relax the requirement for a high reflection fraction and that things are consistent with R=1-2
However … for R=1-2 Fref / Fpl (20-40 keV) ~
while from the plot we get ~ 2 !
Miller et al 08

13. IRAS 13197-1627 with XMM-Newton Absorption is sometimes unambiguous
In these cases, can we disentangle between broad Fe lines and absorption?
Miniutti et al 07

14. IRAS with XMM-Newton
2-12 keV band: an absorbed Compton-thin (4 x 1023 cm-2) AGN, but
Fe K is resolved ( ~ 100 eV, somehow strange for absorbed AGNs)
Transmitted Fe K EW and Fe edge suggest Fe is 1.5 x Solar
Negative residuals in the keV band
Positive residuals > 10 keV and in 5-6 keV band

15. IRAS with XMM-Newton
A different way of looking at the residuals: use a Gaussian filter
Resolved Fe K line
Unresolved Fe K line

16. IRAS with XMM-Newton
A reflection component from the disc potentially could explain both the positive and negative residuals with a broad Fe line and broad Fe edge

17. IRAS with XMM-Newton
We obtain a very significant improvement and running the Gaussian filter once again gives
The residual abs line
is at 6.81 keV
If Fe xxv this implies an outflow with 5000 km/s
But zc=5000 km/s ….
… so we cannot exclude a Galactic origin (McKernan et al 05)

18. NGC 1365 with XMM-Newton
Risaliti et al in prep

19. NGC 1365 with XMM-Newton Similar but with a C-thick cloud
XMM simulation XEUS simulation

20. The “soft excess problem”
The SE is just a definition:
Excess emission with respect to the low-E extrapolation of the 2-10 keV model (power law)
Easiest interpretation:
High-E tail of the disc quasi-BB thermal emission
However, too many problems affect that interpretation

21. The “soft excess problem”
The “temperature” is too hot and too uniform to be real disc BB emission
Several different ideas, but mainly:
Absorption by a relativistic wind (Gierlinski & Done 04 + …)
Reflection from the disc (Crummy et al 06 + …)

22. The “soft excess problem”

23. The “soft excess problem”
1H : a reflection-dominated NLS1 (other interpretations possible)
(Boller et al 02; Fabian et al 02, 05; Gallo et al 05)

24. The “soft excess problem”
the X-ray spectrum can be modelled with only two components

25. The “soft excess problem”

26. The “soft excess problem”
In the case of 1H the light bending model explains
the reflection-dominated spectrum
the Fe K line shape
the variability of the two main spectral components

27. What about X-ray binaries?
In recent years, many examples of disc reflection from BH binaries have been detected
Miller 04, 07

28. What about X-ray binaries?
Most cases (but not all !) during VHS or IS
Miller et al 05

29. What about X-ray binaries?
“Broad Fe line detection is model dependent”
Miller et al 08

30. What about X-ray binaries?
XTE J
XTE J
Belloni et al 04
Miniutti et al 04

31. What about X-ray binaries?
XTE J
XTE J
Miniutti et al 04; Fabian & Miniutti 08
Belloni et al 04

32. Truncated disc in hard state?
GX Fe line does not agree with the idea…
Miller et al 06

33. Truncated disc in hard state?
GX Fe line does not agree with the idea …
The thermal disc in the hard state + its temperature and luminosity suggest that it extends down to the ISCO (or close)
Miller et al 06
Reis et al 08

34. Truncated disc in hard state?
GX Fe line does not agree with the idea …
The Fe line is in fact so broad that it also consistently suggests a disc extending down to the ISCO even in the hard state
Miller et al 06
Reis et al 08

35. Truncated disc in hard state?
Independent fits to the VHS and to the Hard state with complete ref models yield to consistent inner disc radii in both cases (ISCO? If so, very precise spin measurement)
Reis et al 08

36. Truncated disc in hard state?
Maybe GX is somewhat unique?
The truncated disc idea was mainly (not only) based on the absence of a thermal disc in the hard state
XMM+RXTE obs of the newly discovered BH candidate
SWIFT J
RXTE -> strong band-limited noise typical of hard state(LX/Ledd~0.003)
 ~ 1.65
Miller et al 07
The Fe line is in fact so broad that it suggests a disc extending down to the ISCO even in the hard state
Can the transitions occur with a stable disc at the ISCO?