Transcript Dark Ages - Osservatorio Astronomico di Roma-INAF

The First Generation of SMBHs and
Their Host Galaxies
Zoltán (Sołtan) Haiman
Mark Dijkstra, Bence Kocsis
Columbia University
AGN and Galaxy Evolution
Castel Gandolfo
3-6 October, 2005
Outline
1.
Theoretical Expectations
– chemistry and cooling in cosmological models
2.
Growth of the z~6 Quasars
– in hierarchical structure formation theories
3.
Catching Proto-Galaxies in Assembling Stage
– imaging large scale gas infall in Lyα emission
4.
Prospects for Future Detections
– radio counts, gravity waves
Condensations in Hierarchical Cosmology
20
Consider linear
growth of DM
perturbations
in concordance
cosmology
10
Smallest scales
condense first
collapse redshift
30
0
Jeans mass:
~104-5 M
2
3
4
5
log (Mass/ M)
6
7
Modeling the Gas in the First Halos:
Cooling and Chemistry
Collapsed Dark Matter halos virialize,
gas shock heated to virial temperature
Efficient cooling is a necessary condition for
continued contraction following virialization
(i.e. for anything “interesting” to happen)
Primordial gas chemically simple: H, He, H2
Radiative Cooling Function (H+He gas)
log( cooling rate / erg s-1 cm3 )
COSMIC TIME
MASS SCALE
cf. Halo virial temperature:
 M 

Tvir  10  8
 10 M  
4
log( Temperature / K )
2
3
1 z 

K
 11 
Cooling and Chemistry
End of “Dark Age” controlled by
abundance of H2 :
(Saslaw & Zipoy 1967
Haiman, Thoul & Loeb 1996)
Molecular cooling to T~102 K (M~105 M ; z~20)
Atomic cooling to T~104 K (M~108 M ; z~12)
What is the molecular abundance?
nH2/nH ~10-6 after recombination
~10-3 in collapsed objects
Collapse of Spherical Cloud
Gas Phase Chemistry:
H + e-  H- + 
H- + H  H2+ e-
Haiman, Thoul & Loeb (1996)
radius (pc)
103 M
105 M
104 M
106 M
redshift
Clouds with
virial temperature
Tvir ≳ 200 K
can form H2,
cool and collapse
3D Simulations of a Primordial Gas Cloud
Temperature
Density
Abel, Bryan & Norman (AMR)
Bromm, Coppi & Larson (SPH)
Mtot  106 M
z  20
T200 K
n 104 cm-3
M = few 100 M 
f* < 1 %
Gas Phase Chemistry:
H + e-  H- + 
H-+ H  H2+ e-
What forms in these early halos?
• STARS: FIRST GENERATION METAL FREE
- massive stars with harder spectra
- boost in ionizing photon rate by a factor of ~ 20
- return to “normal” stellar pops at Z≳10-3.5 Z⊙
(Tumlinson & Shull 2001 ; Bromm, Kudritzki & Loeb 2001; Schaerer 2002)
• SEED BLACK HOLES: (~102-6 M⊙ )
- boost by ~10 in number of ionizing photons/baryon
- harder spectra up to hard X-rays
- must eventually evolve to quasars and remnant holes
[to z~6 super-massive BHs; probed by gravity waves]
(Oh; Venkatesan & Shull; Haiman, Abel & Rees; Haiman & Menou)
Remnants of Massive Stars
Heger et al. 2003 (for single, non-rotating stars)
metalicity
Z=Z
Z=0
10M
25M 40M
140M 260M
Feedback Processes
• INTERNAL TO SOURCES
- UV flux unbinds gas
- supernova expels gas, sweeps up shells
- H2 chemistry (positive and negative)
- metals enhance cooling
- depends strongly on IMF
• GLOBAL
- H2 chemistry (positive and negative)
- photo-evaporation (minihalos with <10 km/s)
- photo-heating (halos with 10< <50 km/s)
- global dispersion of metals (pop III  pop II)
- mechanical (SN blast waves)
Do most minihalos fail to form stars or black holes?
Global Feedback I. Radiative
Soft UV background:
Soft X-ray background:
this background inevitable
and it destroys molecules
this background from quasars
promotes molecule formation
⊝
⊕
H2 dissociated by 11.2-13.6 eV
photons:
H2+ H2(*) H+H+’
~ 1 keV photons promote
free electrons  more H2
H+  H++e- +’
H + e-  H- + 
H- + H  H2+ eHaiman, Abel & Rees (2000)
Global Feedback II. Entropy Floor?
Oh & Haiman 2003; Kuhlen & Madau 2005
• Star dies after ~106 yrs
and HII region recombines
• Fossil HII region cools off CMB
• T~300 K implies excess entropy
Normalized Entropy
• First star creates ~ 100 kpc
ionized bubble
• Contraction, H2 formation prevented
• Depends on density at illumination
Most of 1st generation objects
may form in more massive halos
Redshift
What happens in Tvir >104K halos?
These halos, as opposed to minihalos,
may be the dominant hosts of the
“first generation” of black holes.
Behavior of gas has not been studied
in same detail as for minihalos (no 3D
simulations).
What happens in Tvir >104K halos?
3/2
 T   n 
8
M J  10 M  4  
3 
 10 K   1cm 
1/2
cf ~100 M for stars
Isothermal atomic cooling at T=104 K:
Jeans mass remains high
most disks would be stable
Oh & Haiman 2001
direct collapse to 106 M BH ?
 need H2 to fragment / form
Bromm & Loeb 2003
stars.Volonteri & Rees 2005
log( cooling rate / erg s-1 cm3 )
Can H2 form in non-equilibrium chemistry?
Oh & Haiman (2002)
Key: gas cools faster
than it recombines,
leaving extra electrons
universal ratio of
n(H2 )/n(H)~10-3
independent of
density, temperature,
background flux
log( Temperature / K )
Conclusion: Tvir >104K halos cool to ~100K
Similar to minihalos:
Rely on H2 cooling and
fragment on similar
(few 100 M  ) scales ?
Main difference:
contract to higher densities
less susceptible to feedback
HD reduces temperature
and fragmentation scale?
Uehara & Inutsuka 2000
Machida et al. 2005
Johnson & Bromm 2005
N.B.: cooling radiation may be observable as Ly ‘fuzz’
(Oh & Haiman 2001; Haiman, Spaans & Quataert 2001)
Outline of Talk
1.
Theoretical Expectations
– chemistry and cooling in cosmological models
2.
Growth of the z~6 Quasars
– in hierarchical structure formation theories
3.
Catching Proto-Galaxies in Assembling Stage
– imaging large scale gas infall in Ly α
4.
Predictions for the Future
– radio counts, gravity waves
High-z Supermassive BHs
Example: SDSS 1114-5251 (Fan et al. 2003)
z=6.43 Mbh 4 x 109 M
How did this SMBH grow so massive?
e-folding (Edd) time:
4 x (/0.1) -1 107yr
No. e-foldings needed
ln(Mbh/Mseed) ~ 20
Age of universe (z=6.43)
8 x 108 yr 
Mseed ~100 M
Growth of High-z Supermassive BHs
z=6.43
CDM merger
tree
z=20
min = 10 km/s
1. Most of the BH mass from z~15 seeds: must start early!
2. High efficiency ( ≳ 0.2) ruled out, unless seeds very massive
3. A super-Eddington accretion phase is required
Assembly history of z=6.43 SDSS quasar
Sum of smaller BHs, each growing exponentially from a stellar seed (Haiman 2004)
Luminosity (Eddington):
Mbh=4.6×109M⊙
Abundance:
Mhalo=1013M ⊙
Assume:
=0.1
=1
min = 30 km/s
Lacey & Cole (1994)
Gravity wave ‘Kick’
of > 100 km/s
redshift
Favata et al. (2004)
Merritt et al. (2004)
Gravitational Lensing of SDSS QSOs
• Expected Lensing Probability at z=6
- intrinsic lensing probability small, ∼10-3
- but magnification bias can boost it to ∼1
(Comeford, Haiman &
Schaye 2003)
• Search for High-Magnification Lensing
- for spherical lens, μ  2 produces multiple images
- No 2nd image on HST images of 4 high-z QSOs
to 0.3” resolution
(Richards et al. 2004)
• Magnification without Multiple Images
(Keeton, Kuhlen &
- ellipticity and/or shear can give high μ
Haiman 2004)
- average over realistic e, γ distributions
- dwarfs (NFW), galaxies (SIS), clusters (NFW)
• Fraction of Lens Systems without a detectable 2nd image
- single image:
5-10% (mostly NFW)
- 2nd image too faint or unresolved: 24-1% (mostly SIS)
Outline of Talk
1.
Theoretical Expectations
– chemistry and cooling in cosmological models
2.
Growth of the z~6 Quasars
– in hierarchical structure formation theories
3.
Catching Proto-Galaxies in Assembling Stage
– imaging large scale gas infall in Ly α
4.
Predictions for the Future
– radio counts, gravity waves
Extended Lyman  Emission
Does the AGN turn or while there is still
significant infall of material from large
(several 100 kpc) scales?

Processed ionizing radiation produced by
embedded AGN (or other ionizing source)
Can we detect contracting extended (size ~Rvir)
hydrogen envelope?
Cooling
radiation from contracting gas
Ly photons scattered from the nucleus
log( cooling rate / erg s-1 cm3 )
Isothermal atomic cooling ?
~ Rvir
sRvir ~ Rvir
10
log( Temperature / K )
Birnboim & Dekel (2003); Maller & Bullock (2004)
Can We Detect the Cooling Radiation?
1. How does cooling halo look like?
“cooling flow” - extended Ly “blob”
JWST limiting line flux at 3 < z < 8:
(Haiman, Spaans & Quataert 2000)
Fα ~ 1016  1017 erg/s/cm 2
mostly Ly emission:
vcirc ≥ 150 km/s
flux spread over Rvir:
θ ~ R vir/d A (z) ~ 5  10"
2. How many halos can we hope to detect ?
blind search in R=5 filter
(narrow filter can go deeper)
~1 halo per JWST field at z=7
~10 halos per field at z=3
3. What if a bright quasar turns on in a collapsing halo?
10-100 times brighter “fuzz”
constrains galaxy formation
(Haiman & Rees 2001)
Lyman  Fuzz Around Young AGN
log(Flux/erg s-1 cm-2 asec-2
Haiman & Rees 2001
• Surface brightness
should be detectable
Weidinger et al. 2005
Bunker et al. 2004
Bergeron et al. 2002
Steidel et al. 2001
Matsuda et al. 2005
log(Tvir/K)
• Challenge:
interpretation of any
possible detection of
spatially resolved
Lyα emission
Ly Transfer Basics
Photons undergo random walk in space+frequency.
Different frequency translates to different m.f.p.
τ ≳ 103
τ ≲ 103
Moderate optical depth:
Extreme optical depth:
photon escapes in wing in
photon escapes in single
single flight.
“excursion”.
Less sensitive to profiles
More sensitive to profiles
Spectrum Emerging from Static Sphere
Red
Blue
Wing
Core
Wing
Gas Infall vs. Outflow (moderate opt. depth)
Monte Carlo
Model assumes:
Dijkstra et al. 2005
gas in NFW halo
power-law v(r)
central ionizing
source (quasar)
CF: Spatially resolved
fuzz around z~4 quasar
(Weidinger et al. 2004)
Effect of Scattering in IGM
Transmission
Through perturbed
IGM
•ρ(r), v(r) around
DM halo (Barkana 2004)
•Ionizing QSO
•Impact parameter
Characteristic
transmission profile
extending to red side
of Lyα line
Gas Infall vs. Outflow
CF: Spatially
resolved spectrum
of Steidel’s LAB # 2
(Wilman et al. 2005)
interpretation:
Ly α generated by
a buried source
absorption by 100
kpc shell, swept-up
by super-wind
Alternative:
IGM infall onto
a density peak
Gas Infall vs. Outflow
IGM infall (Dijkstra et al.)
Absorbing Shell (Wilman et al.)
Spectrum Emerging from Collapsing Sphere
Dijkstra, Haiman & Spaans, in preparation
650 km/s
Red
-1300 km/s
Blue
• Ly radiation emerges blue-shifted, smaller red peak
• IGM opacity can make it hard to detect at high z
Diagnostic of Gas Infall: Brightness Profile
shallow v(r)
steep v(r)
Surface
brightness
profile
radius (arcsec)
• Blue photons come preferentially from central regions
• Surface brightness profiles flat (log. slope of -0.5)
• Scattering vs. Intrinsic effect distinguished using Hα
Outline of Talk
1.
Theoretical Expectations
– chemistry and cooling in cosmological models
2.
Growth of the z~6 Quasars
– in hierarchical structure formation theories
3.
Catching Proto-Galaxies in Assembling Stage
– imaging large scale gas infall in Ly α
4.
Predictions for the Future
– radio counts, gravity waves
Direct Detections in Radio
Haiman, Quataert & Bower (2004)
Model assumes
Mbh  Mhalo5/3 (1+z)
(feedback;
Silk & Rees 1998)
RL distribution from
FIRST-SDSS sample
(Ivezic et al. 2003)
Duty cycle of 2107yr
Minimum BH mass
Mbh >107 M⊙ ?
Gravity Waves from BH-BH Mergers (LISA)
Menou, Haiman & Narayanan (2001); Volonteri et al. (2004)
Tens of mergers per
year detectable in LISA
frequency band.
Can measure Eddington
ratio if quasar counterpart
is found (possible only to
z~1-2)
Many other motivations
Kocsis, Frei, Haiman & Menou
(2005)
Can We Identify a Unique Counterpart?
Kocsis, Frei, Haiman & Menou (2005)
Angular and Radial
localization from GW
signal alone depends
on physical and orbital
parameters and orientation
Angular Error: large, and dominated by LISA uncertainty
Radial Errors: - LISA dL(z) measurement
- Cosmological Model
z ≲ 0.005
- Peculiar velocity
- Lensing-induced variations in dL(z): z  0.03
at z=1
}
Number of Quasars in 3D LISA Error Box
• Extrapolate known optical QSO LF to MBH ≲ 3x107M⊙
• Assume L/L(edd) ~ 0.3, consistent with recent obs+models
• Compute mean number in error box (20% lensing correction)
• Feasible at z<1 for 4x105M⊙ ≲ MBH ≲ 107M⊙
• Can be extended to z=3 if BHs spin rapidly
Conclusions
1.
Hosts of the first generation of BHs:
~108 M⊙ dark matter halos collapsing at z~10
(as opposed to minihalos relying on H2-cooling)
2.
z~6 QSOs are not strongly lensed. Assembling ≳109 M⊙
BHs requires seeds growing uninterrupted since z~15
(and also a super-Eddington growth phase)
3.
Lyα halos may offer diagnostic of early stages of the thick
collapsing gaseous envelopes around proto-galaxies
4.
LISA can measure precise L/LEdd if QSOs accompany GWs
Le Fin