(Massive) Black Hole X-Ray Binaries
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Transcript of (Massive) Black Hole X-Ray Binaries
(Massive) Black Hole X-Ray Binaries
Roger BlandfordKIPAC, 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
• L~1044 (M/1024 gs-1) erg s-1 for L< LEdd ~ 1044M6 erg s-1
M~1.5x1011M6cm~5M6s Innermost Stable Circular Orbit
KIAA2 xi 2010
Lauer et al 2007
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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
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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~-1/2 ~m0.8 =>J~m1.3
• J decreases• Orbit expands• Period lengthens
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Stable Mass Transfer
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cf Hameury et al
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 • (Roche)=90P-2 g cm-3
• Good for N, ISCO (all a)• Accurate interpolation
Lose mass through L1, L22 xi 2010 KIAA
Roche Potential
L1 L2
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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/4r4
dr/dm=1/4r2[S(m),P]=> d log </d log m = =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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Radius-mass relation for
adiabatic stars
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0.3 Mo
~ 2
1Mo
8Mo
~ M
R~M(1-)/3
P~M-/2
RM
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Orbital and stellar evolution
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Mass transfer ratesare quite low, makingadiabatic, conservative assumptions
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Period vs mass
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Post-Roche Evolution After mass transfer orbit expands
• P ~ m-/2
~ m-1 for low mass start-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[Ω*,r(L1)] = LK [rout ]
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X-ray observations Maximum efficiency for
a ~ mPR ~ PISCO
Liberal mass loss• Angular momentum ->Spin • Wind
Equatorial viewing• L ~ D4
• D~2?
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L
E
a=0.99m
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Observed X-ray emission
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a=0 a=0.998i=5
i=30 i=45a=0 a=0.998
i=30
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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” 2 xi 2010 KIAA 22