Accretion and reflection

1
Accretion and reflection in Galactic BHs and
AGNs
Giovanni Miniutti Lab. Astroparticule et
Cosmologie - Paris
The X-ray Universe 2008 - 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
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
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 R1-2 However
for R1-2 Fref / Fpl (20-40 keV) 0.4-0.8
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 13197-1627 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 6.7-7.2 keV
band Positive residuals gt 10 keV and in 5-6 keV
band
15
IRAS 13197-1627 with XMM-Newton
A different way of looking at the residuals use
a Gaussian filter
16
IRAS 13197-1627 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 13197-1627 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
zc5000 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 0707-495 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
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The soft excess problem

• In the case of 1H 0707-495 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
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 J1650-500
XTE J1650-500
Belloni et al 04
Miniutti et al 04
31
What about X-ray binaries?
XTE J1650-500
XTE J1650-500
Miniutti et al 04 Fabian Miniutti 08
Belloni et al 04
32
Truncated disc in hard state?
GX 339-4 Fe line does not agree with the idea
Miller et al 06
33
Truncated disc in hard state?
GX 339-4 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 339-4 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 339-4 is somewhat unique? The
truncated disc idea was mainly (not only) based
on the absence of a thermal disc in the hard state
XMMRXTE obs of the newly discovered BH candidate
SWIFT J1753.5-0127 RXTE -gt strong band-limited
noise typical of hard state(LX/Ledd0.003)
? 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?