Growth & implications of black holes at z > 6 Martin Rees - - PowerPoint PPT Presentation

Growth & implications

• f

black holes at z > 6 Martin Rees (+ Marta Volonteri)

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 Globular Clusters

black hole mass scales with bulge mass stellar velocity dispersion of the bulge

Kormendy 2003

Is this really tighter?

A very early assembly epoch for A very early assembly epoch for QSOs QSOs

The very high redshift quasar SDSS 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)

What happens earlier?

• What are the ‘hosts’ of the first holes?
• How massive are these ‘seed holes’ (stellar -
• - Pop III remnants -- or ‘intermediate’) ?
• How fast can they grow via:

(a) accretion? (b) mergers? How can we probe the highest redshifts (detection, environmental impact, ‘fossils’)?

BARYONS: need to COOL COOL First ‘action’ happens in the the smallest halos with deep enough smallest halos with deep enough potential wells to allow this potential wells to allow this (at (at z~20-30)

Hierarchical Galaxy Formation: small scales collapse first and merge later to form more massive systems

courtesy of M. Kuhlen

First First “ “Population III Population III” ” Stars? Stars?

Swift

PopIII stars remnants

(Madau & Rees 2001, Volonteri, Haardt & Madau 2003)

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 Mseed100Msun

(Fryer, Woosley & Heger)

Bar-unstable self-gravitating gas

(Begelman, Volonteri & Rees 2006)

Transport angular momentum on the

dynamical timescale, process cascades

Efficient viscous angular momentum

transport + efficient gas confinement

Viscous transport

(e.g. Haehnelt & Rees 1993, Eisenstein & Loeb 1995, Bromm & Loeb 2003, Koushiappas et al. 2004)

MBH~103-105 Msun MBH~100-600 Msun

HOW HOW can you make a (super)massive black can you make a (super)massive black hole @ z hole @ z 10-30? 10-30?

How do MBH seeds grow to become supermassiv How do MBH seeds grow to become supermassive e? BH-BH mergers BH-BH mergers vs gas accretion gas accretion The seeds at z>20 are small, The seeds at z>20 are small, ~ ~100-10 100-105

5 M

Msun

sun

Total mass density in MBHs is almost constant in time: just reshuffle the mass function Total mass density in MBHs grows with time

courtesy of L. Mayer

Supermassive holes grow from seed seed pregalactic BHs. . These seeds are incorporated in larger and larger halos, accreting gas accreting gas and dynamically dynamically interacting interacting after mergers. All models for first BHs predict a biased formation: in the

HIGHEST PEAKS OF DENSITY HIGHEST PEAKS OF DENSITY FLUCTUATIONS FLUCTUATIONS at z~20-30

Formation and evolution of supermassive binaries

• 1. Dynamical friction
• 2. Binary hardening

due to stars

• r

accretion of gas

• 3. Gravitational radiation

t a4 t a

Do they merge?

LISA

Will see mergers

• f 105 –107 Msol

black holes

2015+?

Lisa sensitivity to massive black hole binaries

binary 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. Baker et al 2007, Campanelli et al 2007, Gonzalez et al 2007)

• v

vesc

esc from today

from today galaxies galaxies

• v

vesc

esc from high-z

from high-z proto-galaxies proto-galaxies

ESCAPE VELOCITY: ELLIPTICAL GALAXIES DWARF GALAXIES/ MINIHALOS

Gravitational rocket Gravitational rocket

the the gravitational gravitational rocket rocket effect can be a effect can be a threat threat at the highest at the highest redshifts, much less redshifts, much less so at low-z so at low-z

at at z >10 z >10 more than more than 50 -80% 50 -80%

• f merging MBHs can be
• f merging MBHs can be

kicked out kicked out

• f their halo
• f their halo

(Volonteri & Rees 2006,

Volonteri 2007)

Gravitational rocket Gravitational rocket

Build-up of holes by accretion Build-up of holes by accretion

(a) Is there a continuous gas supply continuous gas supply from host halo?

Johnson & Bromm 2007, Pelupessy et al. 2007

(b) When supply is super-critical super-critical: is ’excess’ radiation trapped and/or accretion inefficient, allowing rapid growth in hole’s mass ? Volonteri & Rees 2005 Or is there a radiation-driven outflow? Wang et al. 2006

Wang et al. 2006

(c) What is the influence of spins influence of spins? affect maximal accretion efficiency, importance of Blandford-Znajek energy extraction, etc

High spin high radiative efficiency

Schwarzschild: spin=0 =0.06 maximally rotating: spin=0.998 =0.31 Since for a BH accreting at the Eddington rate the time required to reach a final mass scales as:

Small radiative efficiency

Mfin/Min~105, ~0.1 ⇒ tacc=0.6 Gyr

Large radiative efficiency

Mfin/Min~105, ~0.3 ⇒ tacc=2.2 Gyr

=0.06 =0.3

SDSS 1148+3251

High-z MBHs increase their mass by several High-z MBHs increase their mass by several

• rders of magnitude in a short time!
• rders of magnitude in a short time!

High-z MBH spins High-z MBH spins

mergers can spin BHs either up or down in a sort of random walk accretion spins MBHs up via spin/disc coupling if MaccMBH

Hughes & Blandford 2003

Moderski & Sikora 1996, Volonteri, Madau, Quataert & Rees 2005

Rapidly growing MBHs likely have spins MBHs likely have spins close to maximal close to maximal

Schwarzschild: spin=0 =0.06 tacc=0.6 Gyr maximally rotating: spin=0.998 =0.31 tacc=2.2 Gyr

XMM Fabian et al 02

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

NIR fluxes above the NIR fluxes above the planned JWST sensitivity planned JWST sensitivity soft X soft X– –ray band [0.5 ray band [0.5– –2 keV] 2 keV] > 10 > 101

17 7 erg s

erg s1

1 cm

cm2

2 (XEUS)

(XEUS) >8 Ms CDF-N >8 Ms CDF-N

EM bands: X-ray and NIR EM bands: X-ray and NIR

Future instruments can Future instruments can “ “easily easily” ” detect the early detect the early stages of MBH evolution stages of MBH evolution

Salvaterra, Haardt & Volonteri 2006

soft X soft X– –ray band [0.5 ray band [0.5– –2 keV] 2 keV] > 10 > 101

16 6 erg s

erg s1

1 cm

cm2

2

CDF-N CDF-N 170 arcmin 170 arcmin2

2 2-5

2-5 sources sources

cfr Koekemoer et al. 2003

N(z) (deg -2) 6 7 redshift 9 10 11

“Environmental impacts”

• f Pop III remnants and

black holes at z > 6

X-Rays from low and intermediate mass BHs

• Overall efficiency of accretion exceeds nuclear level.
• Accreting BHs emit a significant fraction of their energy

in X-rays.

• X-rays have a mean free path longer than the non-linear

cosmic length scale.

• X-ray ionization is “inside out”, with low density regions

(partially) ionized first - minimizing recombination losses.

• => Ionization from accreting BHs is efficient.

Diffusion of flux?

How did the flux generated by the jets in Cygnus A

• r by the pulsar

in the Crab Nebula diffuse into ambient or embedded thermal plasma (to the extent indicated by Faraday rotation)?

Production and diffusion of:

‘metals’ <====> ‘seed’ B-field

(Filling factor? Distribution in IGM? Fine-grained mixing?)

• At z=1000 the Universe has cooled

down to 3000K . Hydrogen becomes neutral (“Recombination”).

• At z < 20 the “first” star

(clusters)/small galaxies form.

• At z ~ 6-20 these gradually

photo-ionize the hydrogen in the IGM (“Reionization”).

• At z<6 galaxies form most of their

stars and grow by merging.

• At z<1 massive galaxy clusters

are assembled.

~

Key issues

• Were SMHs ‘seeded’ by Pop III remnants, or

by ‘intermediate mass’ holes?

• How can we detect individual objects out to

z=20?

• What is the ‘environmental impact’? (first

‘metals’, magnetic fields, ionization, etc etc)

• What is relative importance of mergers and

accretion (GR very important!)?