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Accretion flows onto black holes
Chris DoneUniversity of Durham
• Dramatic changes in continuum – single object, different days
• Underlying pattern in all systems
• High L/LEdd: soft spectrum, peaks at kTmax often disc-like, plus tail
• Lower L/LEdd: hard spectrum, peaks at high energies, not like a disc (McClintock & Remillard 2006)
Gierlinski & Done 2003
Spectral states
very high
disk dominated
high/soft
Moving disc – moving QPO• Low frequency QPO – very strong feature at softest low/hard and
intermediate and very high states (disc+tail)
• Moves in frequency: correlated with spectrum• Moving inner disc makes sense of this. Disc closer in, higher f QPO.
More soft photons from disc so softer spectra (di Matteo et al 1999)
DGK07
Reflection from a slab
ioout
out ~ in
1 + in(1- cosio)
in
• Reflection: wherever X-rays illuminate optically thick material. Competition between electron scattering and photoelectric absorption
• Low E – lots of photo-electric absorption by K shell of C,N,O so little reflection
• Higher E – lower abundance of higher Z elements. Less absorption so more reflection
• High E: Compton downscattering e.g. Fabian et al 2000
Reflection from a slab: pexriv
• XSPEC: pexrav
• Low E: reflection probability set by relative importance of scattering and photoelectric abs.
• High E: Compton downscattering so depends on spectral shape above bandpass Magdziarz & Zdziarski 1995
• Makes peak 20-50 keV
Electron scattering
Photoelectric absorption edges
Log
Incident spectrum
Reflected spectrum
Relativistic effects
Fabian et al. 1989
Energy (keV)
flux
• Relativistic effects (special and general) affect all emission (Cunningham 1975)
• Hard to easily spot on continuum components
• Fe Kline from irradiated disc – broad and skewed! (Fabian et al 1989)
• Broadening gives an independent measure of Rin – so spin if ISO (Laor 1991)
• Models predict increasing amount of reflection/line AND increasing width as go from low/hard to high/soft states
Reflected spectra (1)
Gilfanov, Churazov & Revnivtsev 2000
• Predicts increasing solid angle of disk as go from hard to soft
Cyg X-1 fit to power law
Reflected spectra (2)
Gilfanov, Churazov & Revnivtsev 2000
• Many objects SAME correlation and CORRELATED increase in relativistic effects Zdziarski et al., 1999, Gilfanov et al 1999, Zycki et al 1999, Lubinski & Zdziarski 2001, Revnivtsev et al 2001
• But seems more complex in high resolution data….
Log
Log
f
(
Inhomogeneous spectra ?
• Overlap softer (and more reflection)
• Inner region harder (and less reflection)
• WE SEE THIS!!
Mak
ishi
ma,
Tor
ii, T
akah
ashi
…..
• AGN – much more massive so disc in UV
Scale up to AGN
• Dramatic changes in continuum – single object, different days
• Underlying pattern in all systems
• High L/LEdd: soft spectrum, peaks at kTmax often disc-like, plus tail
• Lower L/LEdd: hard spectrum, peaks at high energies, not like a disc (McClintock & Remillard 2006)
Gierlinski & Done 2003
Spectral states
very high
high/soft
‘Spectral states in AGN’
1001010.10.01
Disc BELOW X-ray bandpass. Only see tail
Intrinsic differences in spectrum (same M, different L/LEdd)
• Stretched out by lower disc temperature so not so obvious as in BHB
• BUT range in Lx/Lbol• High mass accretion rates (high
L/LEdd) have lower Lx/Lbol as dominated by UV disc
• Lower mass accretion rates (low L/LEdd) dominated by hard X-rays from hot flow
AGN spectral states
UV disc seen in Quasars!
• Bright, blue/UV continuum from accretion disc.
• Gas close to nucleus irradiated and photo-ionised – lines!
• Broad permitted lines ~ 5000 km/s (BLR)
• Narrow forbidden lines ~ 200 km/s (NLR)
• Forbidden lines suppressed if collisions so NLR is less dense than BLR
Francis et al 1991
AGN/QSO Zoo!!! Optical
• Wider range in mass and spin – all BHB born in similar way but AGN built by accretion
• Fuelling mechanism change:• BHB companion star• maximum mass accretion rate
set by size of binary • 10-6 < L/LEdd<0.5 • Only very few have higher
L/LEdd (GRS1915+105) • Different fuelling of AGN
means not limited in same way – can reach L/LEdd ≥ 1?
Scale up to AGN
Mass of AGN??• Magorrian-Gebhardt relation gives BH mass!! Big black holes live
in host galaxies with big bulges! Either measured by bulge luminosity or bulge mass (stellar velocity dispersion) or BLR
Bla
ck h
ole
mas
s
Stellar system mass
103
109
1061012
• High mass accretion rates (high L/LEdd) have lower Lx/Lbol ie higher Lbol/Lx!
AGN spectral statesV
asuv
aden
& F
abia
n 20
08
Seyfert 1 – Seyfert 2• Intrinsically same except for
obscuration ?
• But differences in HIGH energy spectra (20-200 keV). S1’s softer than S2’s – but also have higher <L/LEdd> than S2 sample so same correlation as in BHB - softer when higher L/LEdd in LHS (Middleton, Done & Schurch 2008; Winter et al 2009)
Seyfert 1 - Quasars
Increasing L
Similar spectra and line ratios, strong UV flux to excite lines,probably similar L/LEdd ~ 0.1-0.3
Increasing M
LINERS-S1-NLS1
Increasing L/LEdd
Similar mass. Different L/LEdd Different ionisation
disc
Hot inner flow, no UV bright disc
LINER
S1
NLS1
Jester 2005; Leighy 2005; kording et al 2007
• No special QSO class – they ALL produce jets, consistent with same radio/X ray evolution
• Jet links to spectral state – hard state has steady radio jet which gets brighter as the hard X-rays get brighter
• Then collapses as make transition to disc (Fender et al 2005)
Gallo et al 2003
And the radio jet… link to spin?
L(X-ray) accretion flow
L(r
adio
) je
t
0.01Ledd
LINERS-S1-NLS1
Increasing L/LEdd
Similar mass. Different L/LEdd Different ionisation
disc
Hot inner flow, no UV bright disc Radio
loudness
Radio quiet
????
LINER
S1
NLS1
Jester 2005; Leighy 2005; Kording et al 2007
Is this all?
• Is this really enough to explain range in behaviour of radio jets?
• Orientation with respect to jet• Strong relativistic beaming
• FRI – BL Lacs – intrinsically weak lines (ie weak UV)
• FRII – Flat spectrum radio QSO – strong lines (strong UV disc)
Is this all?
• FRI – BL Lacs - fluffy• FRII – Flat spectrum radio QSO
Is this all?
Ghisellini et al 2010
Log
Log
f
(
Log
Log
f
(
L/Ledd < 0.01 ADAF, weak disk, low excitationbroader, slower jet, FRI
L/Ledd~1 Disc+tail strong disk, high excitation Narrower, faster jet, FRII
GRS 1915+105 • Hard to get BHB at LEdd as in BINARY. Disc truncated by star so finite reservoir to
build up in quiescence… but BIG binary can!• GRS1915+105 orbital period is 33 days (cf < few days in other BHB). UNIQUE limit
cycle variability in 50% of data - most likely because it goes to uniquely high L (Done Wardzinski & Gierlinski 2004)
Bel
loni
et a
l 200
0
GRS 1915+105
Mir
abel
et a
l 199
8
Log
Log
f
(
Log
Log
f
(
L/Ledd < 0.01 ADAF, weak disk, low excitationbroader, slower jet, FRI
L/Ledd~1 Disc+tail strong disk, high excitation Narrower, faster jet, FRII
Conclusions• BHB – all pretty much 10 solar masses. Good evidence for last
stable orbit at high luminosity. Transition to much harder spectra at lower luminosity. Can be explained by progressive evaporation of inner disc into a hot flow (which is also the base of the jet)
• SAME model can also make sense of the variability, both the low frequency QPO and the broad band noise
• So seems like a pretty good model. So apply to AGN – seems to scale pretty well with mass
• Mass has much bigger spread (105-9 Msun)
• More complex environment – torus/dust obscuration – inclination!
• Spectrum and jet change with L/LEdd but jet may depend on spin as well. Feedback from this controls galaxy formation
Observed disc spectra
Middleton, Davis, Done & Gierlinski 2005
kTe =50 keV• Low/moderate spin as
predicted by SN collapse LMXBs (Gammie et al 2004; a < 0.8)
• Some controversy over GRS1915+105 (Middleton et al
2006; McClintock et al 2006) • Depends on model of
Compton (Torok)• We need slim disc models as
well!! Straub
Observed disc spectra
Middleton, Davis, Done & Gierlinski 2005
kTe free• Low/moderate spin as
predicted by SN collapse LMXBs (Gammie et al 2004; a < 0.8)
• Some controversy over GRS1915+105 (Middleton et al
2006; McClintock et al 2006) • Depends on model of
Compton (Torok)• We need slim disc models as
well!! Straub
