Massive Black Hole X
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Transcript Massive Black Hole X
(Massive) Black Hole
X-Ray Binaries
Roger Blandford
KIPAC, Stanford
+Jane Dai, Steven Fuerst, Peter Eggleton
Massive Black Holes
in AGN
Ubiquitous in normal galaxies (not
dwarfs)
Hole mass related to mass of
bulge and velocity dispersion
Most local black holes are
dormant
When fueled through an accretion
disk
Lauer et al 2007
• L~1044 (M/1024 gs-1) erg s-1 for L< LEdd ~
1044M6 erg s-1
M~1.5x1011M6cm~5M6s
Innermost Stable Circular Orbit
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AGN Stars
Stellar dynamical mass
Sgr A* (Ghez, Genzel)
• 106.6Mo; ~100 OB stars (6Myr)
• S2: 15 yr, e~0.87, rmin~1015.3cm~ 3000m~70 rtid
• Disk distributions?? Invisible stars?
Tidal disruption (Komossa)
• X-ray flares
• Fall back emission
• Fe line reverberation
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Tests of Relativity
Orbital dynamics
Apsidal motion
LT precession
Disk crossings
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[Dai, Fuerst, RB]
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RE J1034+396
•z=0.042 Seyfert galaxy
•Lbol ~ 1044.7 erg s-1
•FUV-SX
•XMM-Newton observations
•1 hr QPO in ~1 d observing
•Best example to date in
AGN of a phenomenon quite
common in stellar XRB
•<Q> ~ 16 overall but much
higher for section of data
•~7% sinusoidal profile
•Interpreted as diskoseismic
mode
•Could it be an EMRI mass
transfer binary?
•Planetars???
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Close Binary Stars
Cataclysmic variables
• WD + “red” star
• ~2000 P>80min
Low Mass X-ray Binaries
• BH/NS + lower mass companion
• ~200 P>11min, LX ~1036-38 erg s-1
Ultra Compact X-ray Binaries
• WD+Ns
• P>5min
Evolve to overflow Roche Lobe through L1
• Accretion disk + hot spot
• Orbits evolve by gravitational, magnetic braking
• Outbursts due to unstable supply, transfer and burning
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Conservative Mass transfer
Transfer m -> M at constant m+M, J
J ~ mMP1/3
If M>>m and gravitational radiation wins,
• dJ/dt~-m2M4/3P-7/3
If m fills Roche lobe,
P~r-1/2 ~m0.8 =>J~m1.3
• J decreases
• Orbit expands
Stable
• Period lengthens
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cf Hameury et al
Mass Transfer
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Relativistic Effects
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Relativistic Roche Problem
Riemann -> local tidal tensor.
Evaluate volume within critical
equipotential and evaluate
•
•
•
•
r(L1)=0.3m1/3 P2/3 Ro
r(Roche)=90P-2 g cm-3
Good for N, ISCO (all a)
Accurate interpolation
Roche Potential
L1
Lose mass through L1, L2
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L2
Pre-Roche evolution
Gravitational radiation dominates
• Need PPN corrections to torque
Low mass star fills Roche lobe when
P=PR=8m0.8hr
[ => m < 0.1 Mo ]
Outside ISCO
• P > PISCO ~ M
[=>M<3x107Mo]
Time to overflow
tR-t=2x105M6-2/3m1.3[(P/PR)8/3-1] yr
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Stellar Evolution
Differs from close binary case
tdynamical << ttransfer << tKelvin
S[m] will be frozen
Solve:
dP/dm=-Gm/4pr4
dr/dm=1/4pr2r[S(m),P]
=> d log <r>/d log m =h
h=2 for convective low mass star
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dS/dm >=0
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Evolution of solar star
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0.3 Mo
h~2
R
Radius-mass relation
for adiabatic stars
M
1Mo
r~ Mh
R~M(1-h)/3
P~M-h/2
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8Mo
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Orbital and stellar evolution
Mass transfer rates
are quite low, making
adiabatic, conservative
assumptions
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Period vs mass
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Post-Roche Evolution
After mass transfer orbit expands
• P ~ m-h/2
~ m-1 for low mass star
t-tR=1400M6-2/3m-1 P8/3 [(P/PR)11/3-1] yr; [~ 5000yr]
Conservative Mass loss
dm/dt = (dm/dt)R = -1.3x1020M0.7P-0.3 g s-1 [~ 1021g s-1]
~ -m8.3 eventually till ttransfer > tKelvin
Dynamical complications
• Holding pattern?
• Interactions, drag
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Mass transfer
Mass flows from L1 onto
relativistic disk forming
hotspot
Gas spirals in to rms before
plunging into hole
Inclined orbits are more
complex as streams may not
self-intersect
Disk flow may have complex
gaps and resonances
Hot spot Doppler beams
emission
Also spiral shocks, eccentricity
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L[*, r ( L1)] L K [ rout ]
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X-ray observations
Maximum efficiency for
a~m
PR ~ PISCO
Liberal mass loss
• Angular momentum ->Spin
• Wind
Equatorial viewing
L
a=0.99m
• L ~ D4
• D~2?
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E
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Observed X-ray emission
a=0
i=5
a=0.998
i=30
a=0
i=30
a=0.998
i=45
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AGN QPOs: other mechanisms
Passage of star through an accretion disk
orbiting a spinning black hole
(Zentsova; Nyakshin; Dai, Fuerst & RB)
• Inclined stellar orbit, apsidal motion, precession
• Inelastic collisions -> beamed X-ray emission
• Ray tracing
Star moving through sub-Keplerian disk
Diskoseismic modes
• Trapped g-modes
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Other observations
17 min IR QPO frm SgrA* (Genzel)
12yr period in OJ287??
• Binary black holes??? (Lehto & Valtonen)
LISA harbingers
• Discover incipient EMRI, coalescence
• Predictable evolution with degree position!
• Seek electromagnetic signal in phase with
~10-9 power
- eg LSST.
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Summary
Observations of quasi-periodic X-ray
emission from stars orbiting black holes in
AGN is a potential probe of general
relativity
RE J1034+396 may not be an example
Reasonable to search AGN X-ray database
for QPO’s with P~5-20hr
AGN black holes could have many
“planetars”
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