black hole binaries€¦ · the final year mm & phinney 2005. 05/16/06 22 spectral evolution...
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Black Hole Binaries
Milos MilosavljevicCalifornia Institute of Technology & Hubble Fellowship
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109108106105 107104103102101
solar masse
stellarbinaries
log cosmic density per log ma
quasars
Milky Way
unknown
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Stefan Gottloeber (AIP, Potsdam) & collaborators
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Owen, O’Dea, Inoue, Eilek, NRAO/AUI, Twin radio jets in Abell 400: two black holes in the same galaxy!
NASA/CXC/MPE/S. Komossa et al. Ultraluminous infrared galaxy NGC6240 contains two accreting black holes separated by 2 kpc.
Rodriguez, Taylor, Zavala, Peck et al. 2006 - see poster!!!
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Mergers Proceed on a Dynamical Time
N-body simulation: Milosavljevic & Merritt 2001
10-100 pc
“Hard” binary forms when black hole separation becomes smaller than the radius of dynamical influence, a < rbh
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position along a slit (arcsec)
rms velocity (km/s)
Joseph et al. 2001, HST/STISRMS stellar velocity at center of dwarf galaxy M32. Central rise σ~(GMbh/r)1/2 is a
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Gravitational Wave Emission
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Simulation: Frans Pretorius (U
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black hole mass (solar mass)
The Final Parsec “Problem”
binary’s semi-major axis (parsec)
GALAXY MERGER
COALESCENCE
diffu
sion Milk
y Way
cor
log(decay timescale)
log(decay radius)
galaxy merger
the bottleneck
coalescencebinary forms
Begelman, Blandford, Rees 1980
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Gravitational Slingshot Interaction
star
binary
U
V cos θ
V sin θ
V sin θ
2U + V cos θ
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The Loss Cone
diffusion
circular orbit
radial orbitMakino & Funato 2004
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Loss cone refilling by merger tides?Zhao, Haehnelt, Rees 2002
T
star
satellite
satellite’s orbital
satellite’s angular velocity
star’s angular velocity
rate at which 1-e changes by order unity
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Loss cone refilling in non-spherical potentialsMagorrian & Tremaine 1999, Yu 2002, Merritt & Poon 2004
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100 pc
HST/ACS VCS, Ferrarese et al
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Gas around Binary Black Holes: Alignment(variant Bardeen-Petterson effect)
Gas Orbits
More Precession
Less Precession
Gas Orbits
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Duchene, McCabe, Ghez & Macintosh 2004,w/Keck at 3.8 μm
GG Tau
GG Tau: Potter/Hawaii/Gemini/AURA/NSF
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Torque Balance and Disk Truncation
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ASC FLASHsimulation,MacFadyen & MM 2006 rbh
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The Final YearMM & Phinney 2005
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The Final YearMM & Phinney 2005
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The Final YearMM & Phinney 2005
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Spectral Evolution
after
before
Thermal accretion disk spectra before and after decoupling and coalescence. Thermal X-ray emission is absent before coalescence.
MM & Phinney 200
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Cosmology with Black Hole Mergers• Gravitational wave train
– luminosity distance but not redshift (redshift degenerate with mass).
– localization: arcminutes to degrees
– thousand host galaxy candidates!
• Monitoring in X-rays at high spatial resolution– afterglow– host galaxy identification,
redshift– “standard candle” (independent
distance and redshift)– confusion due to lensing
• Distance-redshift relation, cosmology
Hughes 2002, Holz & Hughes 2005Kocsis et al. 2006
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Future: MBH Assembly in the Time Domain
MacFadyen & MM, in prep. LSST
Guenther, Schaefer, Kley 2004
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Confusion: Tidal Disruptions!
S. Komossa
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NASA/CXC/SAO
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Stellar mass density as a function of distance from the center of the galaxy: cusps and cores (Gebhardt et al. 1996)
MM 2002, data: Rest et al./WFPC2
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Core Depletion
MM & Merritt 2001
The Mass DeficitDefinition: The mass that had to be removed to produce the observed, centrally-depleted density distribution from a featureless, “universal”profileThe Simulations Yield:
Mdeficit <~ 2 Mbinary(for equal-mass black holes)
Faber et al. 1997, MM et al. 2002
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MM et al. 2002
deficit
black hole masstheoretical prediction for single merger
Are multiple mergers requiredto explain large mass deficits?
Merritt 2006
number of merger generations
deficit
Graham 2004
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Conclusions• Black hole coalescence is expected in the merger
low-mass massive black holes (but radiation recoil and three-body ejections may complicate retention).
• Departures from sphericity lead to efficient loss-cone refilling. Merger tides do not last long enough.
• Accretion around black hole binaries and black hole coalescence will be accompanied by a variety of electromagnetic transients.
• Simultaneous detected of gravitational radiation andelectromagnetic emission will help measure distance-redshift relation.
• Galaxy cores are plausible relics of black holemergers.
• Understanding of the population of low-mass massive black holes a top scientific priority.