review of x-ray variability in black hole binaries · review of x-ray variability in black hole...
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Review of X-ray variability in black hole binaries
Adam Ingram Michiel van der Klis, Chris Done 1234
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The Extremes of Black Hole Accretion 9th June 2015
102 5 20 50
0.1
110
Flux
Energy (keV)
102 5 20 50
0.1
110
Flux
Energy (keV)
102 5 20 50
0.1
110
Flux
Energy (keV)
0.01 0.1 1 10
10−4
10−3
0.01
(rms/
mea
n)2
Frequency (Hz)
0.01 0.1 1 10
10−4
10−3
0.01
(rms/
mea
n)2
Frequency (Hz)
0.01 0.1 1 10
10−4
10−3
0.01
(rms/
mea
n)2
Frequency (Hz)
0.01 0.1 1 10
10−4
10−3
0.01
(rms/
mea
n)2
Frequency (Hz)
0.01 0.1 1 10
10−4
10−3
0.01
(rms/
mea
n)2
Frequency (Hz)
0.01 0.1 1 10
10−4
10−3
0.01
(rms/
mea
n)2
Frequency (Hz)
Wijnands & van der Klis (1998)
Truncated disk model
1 10 1000.01
0.1
110
Flux
Energy (keV)
Flu
x
State changes from moving truncation radius (Rg=GM/c2)
Ro~60Rg
Ro~6Rg
Gilfanov (2010)
4
Diffusion 5
Lynden-Bell & Pringle (1974) Lyubarskii (1997)
Diffusion 6
Lynden-Bell & Pringle (1974) Lyubarskii (1997)
Propagating fluctuations
r1 r2 r3
0.1 1 10
10−4
10−3
Powe
r
Frequency (Hz)
1/tvisc(r1)
1/tvisc(r2)
1/tvisc(r3)
7
Lynden-Bell & Pringle (1974); Lyubarskii (1997); Arevalo & Uttley (2006)
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Propagating fluctuations
30 35 40 45 50 55
0.10.2
r1 r2 r3
Accr
etio
n Ra
te a
t r1
Accr
etio
n Ra
te a
t r2
Accr
etio
n Ra
te a
t r3
X-ra
y Flu
x
0.1 1 10
10−4
10−3
Powe
r
Frequency (Hz)
1/tvisc(r1)
1/tvisc(r2)
1/tvisc(r3)
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Lynden-Bell & Pringle (1974); Lyubarskii (1997); Arevalo & Uttley (2006)
Time (s)
Propagating fluctuations
r1 r2 r3
Propfluc: Ingram & Done (2011, 2012) 0.1 1 10 100
10−3
0.01
Freq
uenc
y x
Powe
r
Frequency (Hz)
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30 35 40 45 50 55
0.10.2
Accr
etio
n Ra
te a
t r1
Accr
etio
n Ra
te a
t r2
Accr
etio
n Ra
te a
t r3
X-ra
y Flu
x
Time (s)
0.04 0.06 0.08 0.1
0.01
0.02
0.03
RMS
(abs
olut
e)
Flux
Propagating fluctuations
r2 r3
Propfluc: Ingram & Done (2011, 2012)
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30 35 40 45 50 55
0.10.2
Accr
etio
n Ra
te a
t r1
Accr
etio
n Ra
te a
t r2
Accr
etio
n Ra
te a
t r3
X-ra
y Flu
x
Time (s)
r1
0.1 1 10 100
10−3
0.01
5×10
−42×
10−3
5×10
−30.
02
Freq
uenc
y x P
ower
([σ/µ]
2 )
Frequency (Hz)
2 rings: χν2=1.008
10 rings: χν2=0.980
20 rings: χν2=0.980
30 rings: χν2=1.014
Propagating fluctuations
r1 r2 r3
Propfluc: Ingram & van der Klis (2013)
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30 35 40 45 50 55
0.10.2
Accr
etio
n Ra
te a
t r1
Accr
etio
n Ra
te a
t r2
Accr
etio
n Ra
te a
t r3
X-ra
y Flu
x
Time (s)
variability has a softer spectrum than fast variability
Freq-resolved spectra 9
Slow and cool
Revnivtsev, Gilfanov & Churazov (1999) Gilfanov, Revnivtsev & Churazov (2000)
Propagation time Fast and
hot
Slow and cool
Kotov et al (2001); Arevalo & Uttley (2006)
Propagation time
Time lags
(8.2-14.1keV) vs (0-3.9keV)
0.1 1 10 100
10−4
10−3
0.01
0.1
Tim
e la
g (s
)
Frequency (Hz)
2 rings: χν2=1.006
10 rings: χν2=0.987
20 rings: χν2=0.996
30 rings: χν2=0.997
Fast and hot
Cyg X-1: Nowak et al (1999) Propfluc: Ingram & van der Klis (2013)
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Hard photons lag soft
Slow and cool
Kotov et al (2001); Arevalo & Uttley (2006)
Propagation time
Time lags Hard photons lag soft Harder photons: greater lag
Fast and hot
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Energy (keV) 10
Cyg X-1: Kotov et al (2001)
QPO: Frame dragging A spinning black hole distorts space and time
The satellite’s motion is influenced by the spin of the black hole
Lense & Thirring (1918) Stella & Vietri (1998)
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Ingram, Done & Fragile (2009)
0 5 10 15 20
4000
6000
X−ray B
rightnes
s
Time (s)
GRS1915+105
QPO: Frame dragging 13
Flux
Energy
Tell-tale sign of precession: a rocking iron line
Ingram & Done (2012)
https://www.youtube.com/watch?v=e1QmLg5mGbU
QPO: Frame dragging 14
Flux
Flux
Time
X-ra
y Br
ight
ness
2045 2050 2055 2060 2065
40006000
8000X−ra
y Brightnes
s
Time (s)
GRS1915+105
Energy Energy
Phase Resolving 15
QPO waveform
0 1 2 3−20
24
68
Total
2nd Harmonic
1st Harmonic
Cycles
16
Periodic function: constant phase difference
0 1 2 3−20
24
68
QPO waveform
Total
2nd Harmonic
1st Harmonic
Cycles
16
Periodic function: constant phase difference
QPO waveform
…but does the phase difference vary randomly or around a well defined mean?
1900 1920 1940 1960
40006000
8000X−ra
y Counts
/s
Time (s)
GRS1915+105
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Quasi-periodic function: changing phase difference
QPO waveform Quasi-periodic function: changing phase difference
Split long light curve into many segments and measure the phase difference ψ for each segment
1900 1920 1940 1960
40006000
8000X−ra
y Counts
/s
Time (s)
GRS1915+105
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QPO waveform Phase difference varies around a mean: there is an
underlying waveform
0 0.5 1 1.5 2
0.5
1N
o of s
egm
ents
(nor
mal
ised
)
ψ / π Ingram & van der Klis (2015)
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GRS 1915+105 (0.46 Hz QPO)
0 0.5 1 1.5 2
4000
5000
6000
Cou
nts/
s
Phase (QPO cycles)
Obs 1
Obs 2
Phase difference varies around a mean: there is an underlying waveform
QPO waveform
Ingram & van der Klis (2015)
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GRS 1915+105 (0.46 Hz QPO)
Phase resolving Spectra for 4 snapshots of phase
20
105
0.8
11.
2R
atio
Energy (keV)
Obs 1GRS 1915+105 (0.46 Hz QPO)
Ingram & van der Klis (2015)
Spectral modeling
QPO phase-resolved spectroscopy 7
105
0.8
11.
2R
atio
Energy (keV)
Obs 1
105
0.8
11.
2R
atio
Energy (keV)
Obs 2
Figure 8. The spectrum corresponding to 4 QPO phases, plotted as a ratio to the mean spectrum. Phases are selected to be representative of rising (blue), peak(black), falling (red) and trough (green) intervals. For observation 1, these phases are φ = 0, 0.1875, 0.625 and 0.75 QPO cycles respectively. For observation2, they are φ = 0, 0.3125, 0.4375 and 0.625 cycles. For both observations, we clearly see spectral pivoting.
4000450050005500
C/s
Observation 1
2.22.32.42.5
K30.7m
0.80.9
1
kTbb
(keV
)
26.1m
6.26.36.4
E c (ke
V) 1.9m
0.20.40.6
m (k
eV) 0.6m
0 0.5 1100150200250
EW (e
V)
Phase (QPO cycles)
2.4m
3000350040004500
C/s
Observation 2
22.052.1
2.15
K 50.4m
0.20.40.6
kTbb
(keV
)
1.0m
6.16.26.36.4
E c (ke
V) 0.3m
0.40.60.8
1
m (k
eV) 0.9m
0 0.5 1100200300
EW (e
V)
Phase (QPO cycles)
3.6m
Figure 9. Best fit parameters of our spectral fit plotted as a function of QPO phase. Both observations show highly significant spectral pivoting and we see amodulation in the relative strength of the iron line. The statistical significance of each modulation is quoted in the corresponding plot.
Ingram & van der Klis (2015)
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3
From NuSTAR to PolSTAR
CZT detectors!
boink!
φ"
LiH scattering rod!
Same CZT detectors!
Image!γ"
γ"
photon detected!
(Launch: 6/2012)!
Compton scattering "in LiH rod!
φ"0! 2π!
# photons!Use to "compute"degree of"polarization!
10/30/14 Copyright 2014 California Institute of Technology. U.S. Government sponsorship acknowledged. log10(flux)
Ro=20Rg, a=0.98
www.youtube.com/watch?v=ieZYYfCapJg&feature=youtu.be
3
From NuSTAR to PolSTAR
CZT detectors!
boink!
φ"
LiH scattering rod!
Same CZT detectors!
Image!γ"
γ"
photon detected!
(Launch: 6/2012)!
Compton scattering "in LiH rod!
φ"0! 2π!
# photons!Use to "compute"degree of"polarization!
10/30/14 Copyright 2014 California Institute of Technology. U.S. Government sponsorship acknowledged.
3
From NuSTAR to PolSTAR
CZT detectors!
boink!
φ"
LiH scattering rod!
Same CZT detectors!
Image!γ"
γ"
photon detected!
(Launch: 6/2012)!
Compton scattering "in LiH rod!
φ"0! 2π!
# photons!Use to "compute"degree of"polarization!
10/30/14 Copyright 2014 California Institute of Technology. U.S. Government sponsorship acknowledged.
Ingram et al (2015)
Polarization 22
• Propagating fluctuations model consistent with power spectrum, linear rms-flux relation, time-lags, frequency-resolved spectra…
• Can now do propfluc analytically, so fitting lots of data is feasible (see Stefano Rapisarda’s talk)
• If the QPO is due to precession, the iron line shape should change with QPO phase
• QPO phase-resolved spectroscopy is now possible (see Abi Stevens’ talk)
• Need to look at more observations
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Conclusions