Black hole formation

1
Black hole formation
?? ? (?????)

• 1. Astrophysical black holes
• 2. Formation of black holes
• 3. Evolution of black holes

Ref Proc. Carnegie sympo. on coevolution of
black holes and galaxies (2003)
http//www.ociw.edu/ociw/symposia/series/symposium
1/proceedings.html
2
Introduction Astrophysical BH formation

BLACK HOLE

• z 20 first objects (?)
• z 6 first quasar (observed)
• z 2 peak quasar density
• z 0 many, many BHs

• Key words
• Co-evolution (with galaxies)
• Feedback (to form structure)

3
Astrophysical black holes Observational facts

• Key questions
• What kinds of astrophysical black holes are
  there?
• What are recent topics about black holes?
• Do they share common properties or not?
• What is known about galaxy-BH connection?

4
Black Hole Candidates
before ?1995
after?1995
galactic nuclei
(quasars)
mass (solar mass)
(NLS1s)
Sgr A
(unknown populations??)
intermediate-mass BHs (ULXs)
gamma-ray bursts (?)
stellar-mass BHs
Our Galaxy
nearby galaxies distant galaxies early
universe
BHs can be found in many places and seem to have
had great influence on the evolution of the
universe.
(c) K. Makishima
5
Black-Hole Objects (1) Stellar-mass BHs (in
binaries)

• Constitute X-ray binaries with normal companions.
• 10 stellar-mass BHs in our Galaxy. (Brown
  Bethe 1994)
• Binary separation

7-9
6
Two spectral states (Galactic BH candidates)
soft
log f?
hard
log h?
hard (low) state power-law, f? ??-a with a
0.7 cutoff at 102 keV
soft (high) state blackbody spec. with kT 1 keV
7
X-ray variability (Cyg X-1) in low/hard state
Negoro (1995)
X-ray light curve (left) and PSD (below)
log PSD
1/f 1.1
1/f 1.5
log f
8
BH mass estimation Stellar-mass BHs in
binaries

• Observe orbital motion of optical companion
• M1 compact star mass, M2 companion mass, i
  inclination, P period

observable
M1 lower limit
radial velocity
Case of GRS 1915105 (Greiner et al. 2001)
orbital phase
9
Black-Hole Objects (2) Massive BHs in galactic
nuclei

• Supermassive BHs seem to lie at the center of
  (active) galaxies.
• HST image of gas (dust) disk surrounding a
  central black hole.
• Occasionally associated with jet(s).

10
(No Transcript)
11
Spectra of Sy 1 type AGNs
log?f?
BBB
power law exp. cutoff
log h?
Big Blue Bump (UV) blackbody with Teff 105
K (10 eV)
power law (radio ?) f???-a with a 0.7
cutoff at 100-200 keV
How do we understand such SED by disk models?
12
BH mass estimation Massive BHs in galactic
nuclei

• Stellar kinematics
• Detect proper motions of individual stars
  (Galactic center)
• Stellar absorption-line kinematics (galaxies with
  distances, d lt 20 Mpc)
• Optical emission-line gas
• Distances of up to d lt 100 Mpc, BH mass of MBH gt
  107 Msun
• H2O Masers
• Line width radius ? MBH (1-40)106Msun up
  to d 70 Mpc.
• Reverberation (echo) mapping
• Cont.-line time delay, ?t ? rBLR c?t (
  distance to BLR)
• BLR line width (GMBH/rBLR)1/2 ? MBH
• X-ray variability scaling (timescale ? MBH )

13
BH-host galaxy correlations

• MBH Mbulge relations (normal gal.)
• ? MBH /Mbulge ? 0.005 (Kormendy Richstone
  1995Magorrian et al. 1998)
• ? MBH /Mbulge ? 0.001 (Kormendy 2000 Merritt
  Ferrarese 2001)
• ? MBH ?Mbulge1.53 MBH /Mbulge ? 0.005 (MV
  ?-22) 0.0005 (MV ?-18) (Laor 2001)
• MBH Mbulge relations (AGN)
• ? MBH /Mbulge ? 0.005 in QSOs (Laor 1998)
• ? MBH /Mbulge? 0.0005 in Sy 1s (Wandel 1999
  Gebhardt et al. 2000 Nelson 2000)
• MBH s(velocity dispersion) relation
• ? MBH???, ?4.72 (Ferrarese Merritt 2000
  Merrit Ferrarese 2000)
• ? MBH???, ?3.75 (Gebhardt et al. 2000)

14
BH to bulge mass ratio
Magorrian (1998)
MBHM
Seyfert
Merritt Ferrarese (2001)
15
(No Transcript)
16
Other BH-host galaxy correlations

• Cusp slope absolute magnitude (Gebhardt et al.
  2000)
• Sersic index - vel. dispersion - BH mass (Erwin
  et al. 2003)
• Bulge light profile ?r1/n n Sersic index

cusp density slope
Brighter galaxies have flatter density slopes
absolute magnitude
17
Narrow-Line Seyfert 1 galaxies (NLS1s)
Boller et al. (NewA 44, 2000)

• What are NLS1s?
• Narrow broad lines (lt 2000 km s-1)
• Sy 1 type X-ray features
• Extreme soft excess
• Extreme variability
• Spectral features resemble GBHCs
• Seem to contain less massive BHs
• High Tbb (?MBH-1/4) ? large soft excess
• Small (GMBH/RBLR)1/2 ? narrow line width

18
Intermediate-Mass Black Holes (IMBHs)
van der Marel (Carnegie sympo., 2003)

• Ultra Luminous X-ray sources (ULXs)
• Successively discovered with X-rays in nearby
  galaxies
• Luminosity is LX gt 1039 erg s-1 gt (LE of a
  neutron star)
• QSS (quasi-soft source) may be low luminosity
  IMBHs (?)
• 
  (Kong Di Stefano 2003)
• IMBHs through grav. microlensing
• No IMBH MACHOs in LMC.
• Some of Galactic bulge MACHOs could be IMBHs,
  since
• microlens timescale, 130 (M/Msun)1/2 d,
  exceeds 130d.
• IMBH in globular clusters(?)
• Still controversial. Needs confirmation.

19
X-ray spectra of ULXs
(c) A. Kubota

• MCD (multi-color disk) type
• PL (power-law) type
• Transition between MCD?PL

Alike Galactic BHCs
IC342 galaxy
20
Black hole accretion in GRBs(?)
(Narayan, Paczynski Piran 1992 Narayan, Piran
Kumar 2001)

• Central engine of GRBs?
• NS-NS/BH-NS merger
• BH-He core merger
• failed supernovae
• (collapsar)
• magnetar
• Two basic timescales
• dynamical t.s. (rS3/GM)1/2 lt 0.1 sec
• viscous t.s. (r/H)2(rtorus3/GM)1/2 1-100 sec

massive torus around a BH Mtorus0.011
Msun MBH 310(?) Msun
21
Primordial black holes (PBHs)
(Carr 2003,
astro-ph/0310838)

• Primordial density perturbations may lead to
  grav. collapse
• 
  (Zeldovich Novikov 1967 Hawking 1971)
• Small BHs should have
• evaporated already
• Constraints for ß (fraction of
• regions of mass M which collapse)
• ?

OPBH lt 1
? emission
22
2. Formation of BHs Stellar-mass to
massive BHs

• Key questions
• How do massive stars end their lives?
• How can supermassive BHs be formed,
  Collapse or mergers?
• How are quasar formation related to galaxy
  formation? Which are the first objects,
  stars (galaxies) or BHs?

23
End product of stars

• Present-day stars
• Massive stars shed most of their mass through
  wind.
• Massive stars leave compact remnants with M lt 15
  Msun
• The minimum initial mass to produce a BH is
  20-25 Msun
• Metal-free (Pop. III) stars
• Typical mass is 100 Msun
• Stars with M lt 140 Msun probably evolve into
  BHs.
• Stars with M 140260 Msun leaves nothing (pair
  instability).
• Stars with M gt 260 Msun directly collapse to
  IMBHs.

24
Star evolution remnant mass
Heger Woosely (ApJ 591, 288, 2003)
1 3 10 30 100
300
remnant mass (Msun)
WD
BH
NS
BH
initial mass (Msun)
1 9 28
140 260
25
How massive single stars end their life?
Heger et al. (ApJ 591, 288, 2003)

• Fate of a massive star is governed by
• (1) its mass,
• (2) chemical composition,
• (3) mass loss.

metal poor solar
initial mass (Msun)
9 25 40 60
100 140 260
26
Rees diagram - how to make a massive BHs?
(Rees ARAA 22, 471, 1984)
collapse of a massive object or mergers in a
cluster
27
Direct collapse of a gas cloud
Bromm
Loeb (ApJ 596, 34, 2003)

• Basic scenario a metal-free primordial clouds
  of 108Msun
• ? condensations of
  5106Msun
• ? collapse to a BH
• A cloud avoids fragmentation into stars by
  background UV radiation.

28
General Relativistic Instability Baumgarte
Shapiro 1999, ApJ, 526, 941 Rapidly rotating
supermassive star in equilibrium
critical point
stable
unstable
? rigid rotation ? mass-shedding limit ? unstable
at
massive objects ? Prad gt Pgas ? ?4/3 ?
instability GR unstable even if ?gt 4/3
29
Dynamical Collapse (Full General Relativity)
(Shibata Shapiro 2002, ApJ, 572, L39)
Dynamical collapse ? Apparent Horizon Kerr
parameter ? 0.75 (Kerr BH)

30
BH formation in dense clusters
(van der Marel 2003)

• Basic idea
• Self-gravity gives negative heat capacity ?
  gravo-thermal catastrophe ? formation of high
  density core ? BH
• Runaway merging occurs in dense clusters (?gt
  106Msun pc-3) of many stars (N gt 107) (Lee
  1987, Quinlan Shapiro 1990). ? IMBH ?
  (accretion) ? SMBH
• Problem
• Formation of an BH does not occur in clusters
  with N lt 107 because binary heating halts core
  collapse (Hut et al. 1992). (Three-body
  interactions between binaries and single stars
  add energy to the cluster.)

31
Conditions for runaway collapse
(Rasio et al. Carnegie sympo.
2003)
Solution mass segregation Heaviest starts
undergo core collapse independently of the
other cluster stars ? runaway collapse ?
formation of an IMBH if core collapse time
lt main-sequence lifetime (Pontegies Zwart
McMillan 2002).
32
From IMBHs to SMBHs
(van der Marel 2003)

• Merging
• Pop. III stars ? IMBHs ? IMBHs sink to the center
  of proto-galaxies ? SMBH (Schneider et al.
  2002 Velonteri et al. 2003).
• SMBHs that grow through mergers generally have
  little spin, difficult to power radio jets
  (Hughes Blandford 2003).
• Accretion
• Collapse of a proto-galaxy onto a BH (Adams et
  al. 2001)
• Accretion of material shed by stars (Murphy et
  al. 1991).
• Feedback from energy release near the center may
  limit growth of the BH and of galaxy (Haehnelt
  et al. 1998 Silk Rees 1998).
• Feedback from star formation may also (Burkert
  Silk 2001).

33
Inter-mediate mass BHs to Supermassive BHs
(coutesy of T. Tsuru)
34
3. Evolution of BHs Quasar LFs BH mass
density

• Key questions
• What do we learn from the observed QSO
  luminosity functions (LFs)?
• What do we know about current BH density? Any
  useful constraints on BH accretion?
• How can we model QSO formation scenarios?

35
Quasar (BH) evolution
(Rees 1990)

• Quasars co-moving density reached its maximum
  at z 2.

36
Evolution of Quasar Luminosity Functions (LFs)
High z QSO LFs from SDSS (z 4.3 Fan et al.
2001)
QSO LFs from 2dF QSO redshift survey (0 lt z lt
2.3 Boyle et al. 2000)
37
Cosmological evolution of AGN spatial density
Ueda et al. (ApJ, 2003)

• Number density of higher luminosity AGNs peaked
  at higher redshifts.

Similar evolutions are found for star-formation
rates.
38
BH mass density (1).From quasar luminosity func.
Yu Tremaine (MN 335, 965, 2002)

• 2dF redshift survey (Boyle et al. 2000)
• ? ?BH(z) ?(dt/dz)dz?Lbol (1 -e)/(ec2)
  ?(L,z)dL
• ? ?BH(0) (2-4)105 h0.652 Msun Mpc-3 (for
  e 0.1)

Hosokawa (2002)
39
Obscured BH accretion
(Haehnelt 2003)

• If some fraction of AGN are obscured, energy
  conversion efficiency is smaller ? BH density
  should be higher.

40
BH mass density (2).From galaxy velocity-disp.
Yu Tremaine (MN 335, 965, 2002)

• Sloan Digital Sky Survey
• ? s velocity dispersion (early type
  gal.)
• ? MBH (1.50.2)108 Msun (s/200 km
  s-1)40.3
• ? ?BH (2.50.4)105 h0.652 Msun Mpc-3
• Consistent with the previous estimates, if e 0.2
• (Soltan 1982 Choksi Turner 1992 Small
  Blandford 1992 )

41
Theoretical models of quasar lum. func.
(Haehnelt et al. 1998 Haiman Loeb 1998)

• Model assumptions (previous models)
• Press-Schechter formalism ? Mhalo distribution
• Black holes immediately merge when two halos
  merge.
• Empirical Mhalo- MBH relation ? MBH
  ratioparameter
• Simple light variation L LE exp(-t/te) te
  parameter
• Simple spectrum ? LFs at optical/X-rays
• Our model (Hosokawa et al. 2001, PASJ 53, 861)
• Realistic quasar model spectra absorption
• Disk luminosities do not depend on MBH, but
  spectra do,
• since the BBB peak frequency, ?peak? MBH-1/4

42
Calculated quasar LFs at z3
Hosokawa et al. (PASJ 53, 861,
2001)

• X-ray B band LFs are well reproduced
  simultaneously.
• IR band LFs are sensitive to spectral shape (thus
  MBH).

Data from X Miyaji et al. (1998)
B Pei (1995)
43
Which model is correct?
Hosokawa (ApJ 576, 75, 2002)

• Model A MBH? Mhalo5/3 (Haehnelt et al.
  1998)
• Model B MBH? Mhalo (Haiman Loeb 1998)
• life-time MBH /Mhalo
• Model A 107-8 yr 10-4.5
  
• Model B 105-6 yr 10-3.5
  
• Model B over-predicts current BH mass
  density.
• Quasar life-time estimates by Yu Tremaine also
  support Model A. Mean life time (3-13)107
  yr

present-day BH mass func.
model B
model A
log(d?/dlog MBH)
log(MBH/Msun)
44
Silk-Rees picture for quasar-galaxy connection
Silk Rees (AA 331, L1, 1998)

• Which are firstly formed, stars or BHs?
• If BHs are first, significant effects from BHs to
  star formation. (quasar peak at z gt 2, while
  galaxy formation at z 1.5).
• Then, there exists maximum BH mass
• Maximum feeding rate towards the center M
  ?(stff)3/tff s3/G
• A quasar expels all this gas from the galactic
  potential well on a dynamical timescale if Ms2
  lt L LEdd ? no further BH growth
• This condition gives maximum BH mass
• MBH lt s5?/G 2c 8108 (s/500 km
  s-1)5 Msun

.
.
45
Radiation drag model for quasar BH formation
Umemura (ApJ 520, L29, 2001)

• mass accretion rate (t1 limit)
• accretion time
• radiation energy from stars
• massive dark object

(? 0.007 H ? He nuclear fusion energy
conversion efficiency)


46
Semi-analytical model (1)
Kauffmann Haehnelt (MN 311, 576, 2000)
Merging trees of dark halos
gas cooling, star formation, SN, feedback,
SMBHs form from cold gas in major mergers.

• MBH sigma relation

47
Quasar evolution and galaxy evolution
Franceschini et al. (MN 310, L5, 1999)
Quasar density vs. star-formation rate (SFR)

• Opt-UV observations of field galaxies
  ? star-formation rate (SFR)
• Same but for field elliptical galaxies
  ? star-formation rate (SFR)
• ROSAT (soft-X) survey
  ? 0.5-2 keV vol. emissivity of
  high luminosity quasars

z
48
Semi-analytical model (2) Evolution
Kauffmann Haehnelt (MN 311, 576, 2000)

• Rapid declne in quasar density from z 2 to z
  0 is due to
• (1) less frequent mergers, (2) depletion of
  cold (accretion) gas, and (3) incrase in
  accretion timescale.

z
z
quasar density evolution SFR
evolution
49
Semi-analytical model (3) Assemby history
Haehnelt (2003)

• BH growth Build up starts at z 6 - 8 and grow
  to 109 Msun
• Occasionally super-critical
  accretion appears.

bright bulge faint bulge
50
How can we make a massive BH at z 5.8
Haiman Loeb (ApJ 552, 459, 2001)
SDSS 1044-0125 at z 5.80 (Fan et al. 2000) ?
MBH 3.4109 Msun

• Salpeter timescale (e-fold time)
  Mc2/LEdd 4107 yr
• Growth time for a 10 MsunBH to 3.4109 Msun via
  accretion
  7108 (e/0.1)?-1 yr
  age of universe at z 5.8
• Lensing? Super-critical accretion??

required
L LEdd
.
minimum ? L/LEdd vs. eL/Mc2
51
Open questions
(Haehnelt 2003)

• Is AGN activity triggered by mergers? What is
  the timescale of QSO activity and what determines
  it? Why is it apparently shorter than the merger
  timescale of galaxies?
• How much room is there for dark or obscured
  accretion? Can the accretion rate exceed the
  Eddington limit?
• What is the physical origin of the MBH-s
  relation? Does it evolve with
  redshift?
• What role do SMBHs play in galaxy formation and
  in defining the Hubble sequence of galaxies?
• Are supermassive binary BHs common?
  On which timescale
  do they merge?
• Do IMBHs form in shallow potential wells?
  Does the MBH-s relation extend to
  smaller BH masses?

52
Summary possible BH formation paths
PBH
Pop.III
stars
star cluster
IMBH
stellar-mass BH
runaway collapse
evaporation
merger/ accretion
merger/ accretion
IMBH
?? stellar-mass IMBH
SMBH BH