Post on 11-Jan-2016
MASSIVE BLACK HOLES:formation & evolution
Martin Rees
Cambridge University
Themes of this symposium
1*. Radiation, ,accretion jets, winds, etc --- phenomenology and models.
3C31:
OpticalRadio
Themes of this symposium
1*. Radiation, ,accretion jets, winds, etc --- phenomenology and models.
2*. Do ‘holes’ obey the Kerr metric (testing strong-field GR, etc)?
* straightforward scaling laws between
stellar-mass and supermassive holes
Themes of this symposium
1*. Radiation, ,accretion jets, winds, etc --- phenomenology and models.
2*. Do ‘holes’ obey the Kerr metric (testing strong-field GR, etc)?
3. Population and demography of supermassive holes: how do they form and evolve?
* straightforward scaling laws between
stellar-mass and supermassive holes
Observational progress in demography and evolution of
holes(I) Ubiquity of holes in galaxies
Massive black holes?
Yes Yes but black hole mass scales with bulge mass not
total mass
Some at least
Maybe
Giant Ellipticals/S0s Spirals Dwarfs GlobularClusters
black hole mass scales with bulge mass
stellar velocity dispersion of the bulge
Kormendy 2003
Is this really tighter?
Observational progress in demography and evolution of
holes(I) Ubiquity of holes in galaxies
(II) Feedback from hole to galaxy
New clues from deep Chandra observations of Perseus
Fabian et al 03a,b
Observational progress in demography and evolution of
holes(I) Ubiquity of holes in galaxies
(II) Feedback from hole to galaxy
(III) Objects discovered at z > 6 .
A very early assembly epoch for A very early assembly epoch for QSOs QSOs
The highest redshift quasar currently knownSDSS 1148+3251 at z=6.4
has estimates of the SMBH mass MBH=2-6 x109 Msun (Willott et al 2003, Barth et al 2003)
As massive as the
largest SMBHs today,
but when the Universe
was <1 Gyr old!
THE HIGHEST-REDSHIFT QUASARS
Becker et al. (2000)
Fluctuation generator
Fluctuation amplifier
(Graphics from Gary Hinshaw/WMAP team)
Hot Dense SmoothCool Rarefied
Clumpy
Brief History of the Universe
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BARYONS: need to COOLCOOL First ‘action’ happens in the the
smallest halos with deep smallest halos with deep enough potential wells to allow enough potential wells to allow
this this (at (at z~20-30)
Hierarchical Galaxy Formation:
small scales collapse firstand merge later to form more massive systems
courtesy of M. Kuhlen
First ‘seed’ black holes?First ‘seed’ black holes?
PopIII stars remnants(Madau & Rees 2001,
Volonteri, Haardt & Madau 2003)
Viscous transport + supermassive star (e.g. Haehnelt & Rees 1993, Eisenstein & Loeb 1995, Bromm & Loeb 2003, Koushiappas et al. 2004)
Efficient viscous angular momentum
transport + efficient gas confinement
First black holes in pregalactic halosFirst black holes in pregalactic halosz≈10-30z≈10-30
Simulations suggest that the first stars are massive M~100-600 Msun
(Abel et al., Bromm et al.)
Metal free dying stars with M>260Msun leave remnant BHs with Mseed≥100Msun (Fryer, Woosley & Heger)
Bar-unstable self-gravitating gas + large “quasistar” (Begelman, Volonteri & Rees 2006)
Transport angular momentum on the dynamical timescale, process cascades
Formation of a BH in the core of a low entropy quasistar ~104-106 Msun
The BH can swallow the quasistar
MBH~103-106 Msun MBH~100-600 Msun
Supermassive holes grow
from seedseed pregalactic BHs..
These seeds are incorporated
in larger and larger halos,
accreting gas accreting gas and dynamically dynamically
interacting interacting after mergers.
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All models for first BHs predict
a biased formation: in the
HIGHEST PEAKS OF DENSITY HIGHEST PEAKS OF DENSITY
FLUCTUATIONSFLUCTUATIONS at z~20-30
Quasar host
Dark matter Galaxies
Mh= 5 x 012M
Mh= 51012M M*
= 1011M
SFR = 235 M /yr MBH
= 108M
Quasars end up in cD galaxies at centres of rich galaxy clusters
today
Mh= 2 x 1015M
Descendant
Mh= 21015M
Formation and evolution of supermassive binaries
1. Dynamical friction
2. Binary hardening due to stars
or accretion of gas
3. Gravitational radiation
t a4
t a
Do they merge?
LISA
Will see mergersof 105 –107 Msol
black holes
2011?
Lisa sensitivity to massive black hole binaries
Dependence of merger rate on mass of minihalos in which first holes form
DWARF GALAXIES/MINIHALOS
ELLIPTICAL GALAXIES
mass
Vesc
(km
/s)
1000
100
10
109 1013
VVre
coil
reco
il
(km
/s)
(km
/s)
Gravitational rocketGravitational rocketbinary center of mass recoil during coalescence due to binary center of mass recoil during coalescence due to
asymmetric emission of GW asymmetric emission of GW (e.g. Fitchett 1983, Favata et al 2004, Blanchet et al 2005, Baker et al 2006)
vvrec rec ≤ 250 km/s≤ 250 km/s
««vvesc esc from today galaxies from today galaxies
≈≈vvesc esc from high-z onesfrom high-z ones
GR SIMULATIONS
at z >10 more than 80% of merging MBHs can be kicked out of their halo(Volonteri & Rees 2006)
the gravitational rocket effect is a
threat at the highest redshifts, when host halos are small and
have shallow potential wells
Can the merger process start early enough toCan the merger process start early enough toAllow build-up of supermassive holes?Allow build-up of supermassive holes? Can the merger process start early enough toCan the merger process start early enough toAllow build-up of supermassive holes?Allow build-up of supermassive holes?
Build-up of holes by accretionBuild-up of holes by accretion
(a (a) Is there a continuous gas ) Is there a continuous gas supply from host halo?supply from host halo?
(b) When supply is super-critical:, (b) When supply is super-critical:, is ’excess’ radiation trapped and/or?is ’excess’ radiation trapped and/or?
accretion inefficient, allowing rapid growth accretion inefficient, allowing rapid growth in hole’s mass ? in hole’s mass ?
Or is there a radiation-driven outflow?Or is there a radiation-driven outflow?
(spin?)(spin?)..
NOTE; Classic argument of Soltan (1982), which compares total mass of holes with total radiative
output, implies that most of the mass is gained via ‘efficient’ accretion.
But most ot the ‘e-folds’ (eg first 10% of mass) could be gained rapidly via inefficient accretion
from Yu & Tremaine 2002
SMBH
=2.5-3.5x105M Mpc-3
~0.2 @ z<5
qso(0)
=2.1x105[0.1(1-)/]M Mpc-3
Elvis, Risaliti & Zamorani 2002
Eddington accretion
=0.2
super-Eddington accretion
Are massive black holes rapidly spinning? (affects maximal accretion
efficiency, minimum variability timescale, importance of Blandford-
Znajek energy extraction, etc)
Spin is modified by BH mergers and Spin is modified by BH mergers and the coupling with the accretion discthe coupling with the accretion disc
mergers can spin BHs either up or down;
alignment with the disc spins up
spin evolution by BH mergers only
spin evolution by BH mergers AND accretion
1. Mass of the BH 1. Mass of the BH seedseed
PopIII stars remnants
MBH~100-600 Msun
Gas collapse via Post-Newtonian instability
MBH~105-106 Msun
2. BH mergers2. BH mergers
Positive contribution:build-up of high masses
Negative contribution(gravitational rocket)
3. Accretion rate 3. Accretion rate
Eddington-limited(continuous or intermittent)
Super-Eddington(Excess swallowed or expelled?)
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