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WMAP Implications for Reionization. Zolt á n Haiman. Columbia University. The Davis Meeting on Cosmic Inflation 22-25 March, 2003. Looking for Electrons with WMAP. [marginalized errors from TE correlation]. (Spergel et al. 2003). Z(reion)=6  0.04.

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wmap implications for reionization
WMAP Implications for Reionization

Zoltán Haiman

Columbia University

The Davis Meeting on Cosmic Inflation 22-25 March, 2003

looking for electrons with wmap
Looking for Electrons with WMAP

[marginalized errors from TE correlation]

(Spergel et al. 2003)

Z(reion)=6  0.04

outline of talk
Outline of Talk
  • Theoretical Modeling of Reionization –what were the sources? –what are the key feedback processes?
  • Observational Signatures – distribution of neutral hydrogen – distribution of free electrons
the dark age
The Dark Age

(Chandra)

Current horizon:

z=6.6

Reionization:

z 7-20

Recombination:

z 1000

what were the sources of reionization
What were the sources of reionization?
  • Not a stringent energetic requirement
  • - 13.6 eV (chemical) vs >MeV (nuclear or grav.)
  • Non-linear structures are present early in most cosmologies(*)
  • - 2-3 peaks above Jeans scale collapse at z=20-30
  • Photo-ionization natural candidate
  • - consistent with Lyman  forest at lower z
  • - stars vs quasars
  • - decaying particles require fine-tuning of , m

(*) Interesting exceptions

extra stars or quasars are needed

Quasar space density

Star formation rate

log [n(z) / n(peak)]

log [d* /dt/M yr-1 Mpc-3]

redshift

redshift

(Haiman, Abel & Madau 2001)

Extra Stars or Quasars are Needed

2

1

?

?

0

-1

Z

Z

relevant halo mass scales
Relevant Halo Mass Scales

(masses at redshift z=10)

  • Jeans Mass104 M⊙ Tvir=20 Kx 20
  • H2 cooling105 M⊙ Tvir=102 K TYPE II 17
  • HIcooling108 M⊙ Tvir=104 K TYPE Ia9
  • Photo-heating1010 M⊙ Tvir=2x105 K TYPE Ib 5

2 peak

redshifts

what forms in these early halos
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≳10-4 Z⊙
  • (Tumlinson & Shull 2001 ; Bromm, Kudritzki & Loeb 2001; Schaerer 2002)
  • SEED BLACK HOLES: PERHAPS MASSIVE (~106 M⊙ )
  • - boost by ~10 in number of ionizing photons/baryon
  • - harder spectra up to hard X-rays
  • - effects topology, IGM heating, H2 chemistry
  • - connections to quasars and remnant holes
  • [especially z~6 super-massive BHs; also gravity waves]
  • (Oh; Venkatesan & Shull; Haiman, Abel & Rees; Haiman & Menou)
feedback processes
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 TYPE II)
  • - photo-evaporation (TYPE Ia)
  • - photo-heating (TYPE Ib)
  • - global dispersion of metals (pop III  pop II)
  • - mechanical (SN blast waves)

first global feedback
First Global Feedback

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:

~ 1 keV photons promote

free electrons  more H2

H2+ H2(*) H+H+’

H+  H++e-+’

“sawtooth

spectrum”

H + e- H- + 

H-+ H  H2+ e-

Haiman, Abel & Rees (2000)

second global feedback
Second Global Feedback

PHOTO-IONIZATION HEATING:

- IGM temperature raised to ≳104K

- Gas in-fall suppressed in halos with

velocity dispersion  ≲ 50 km/s

- [or: Jeans mass increased…]

0D: Efstathiou 1992

1D: Thoul & Weinberg 1995

3D: Navarro & Steinmetz 1997

reionization histories electron fraction
Reionization Histories (electron fraction)

TYPE Ib

TYPE Ia

TYPE II

(Haiman & Holder 2003)

outline of talk1
Outline of Talk
  • Theoretical Modeling of Reionization –what were the sources? –what are the key feedback processes?
  • Observational Signatures – distribution of neutral hydrogen – distribution of free electrons
percolation is occurring at z 6 7
“Percolation” is occurring at z~6-7

looking for hydrogen

  • Spectra of z~6 quasars in SDSS
  • - Gunn-Peterson troughs at z > 6
  • - Compared to HI opacity in 5.5 ≲ z ≲ 6 sources
  • (Becker et al. 2001; Fan et al. 2002, Songaila & Cowie 2002)
  • IGM Temperature
  • - IGM inferred to be warm from z~6 Lyman  forest
  • - It would be too cold for single early reionization
  • (Hui & Haiman 2003; Zaldarriaga et al. 1997; Theuns et al. 2002)
evolution of the ionizing background
Evolution of the Ionizing Background

Fan et al. (2002)

  • Sharp drop at z~6
  • Natural post-percolation
  • Difficult to explain otherwise
  • Similar conclusions in:
  • Lidz et al. 2002
  • Cen & McDonald 2002
  • Gnedin 2002
  • Songaila & Cowie 2002

Ionizing background (10-12 s-1 )

redshift

another piece of evidence for z r 10
Another Piece of Evidence for zr ≲ 10

Hui & Haiman (2003)

IGM quite warm at z~4

- measured T  20,000 K

- adiabatic cooling vs.

photo-ionization heating

- requires a percolation

at low redshift (z<10)

(Zaldarriaga et al. 2001; Theuns et al. 2002)

reionization history
Reionization History

Haiman & Holder 2003

0.08

0.08

electron fraction

redshift

redshift

N=4000

f*=20%

fesc=10%

C=10

Wyithe & Loeb; Ciardi et al.

Somerville et al.; Sokasian et al.

Fukugita & Kawasaki; Cen

Nf*fesc/C=8

reionization history1
Reionization History

Haiman & Holder 2003

TYPE II

0.17

0.08

electron fraction

redshift

redshift

N=40000

f*=0.005

fesc=100%

C=10

=20

reionization history2
Reionization History

Haiman & Holder 2003

0.17

TYPE II

0.17

TYPE Ia

electron fraction

redshift

redshift

N=40000

f*=0.005

fesc=100%

C=10

N=40000

f*=20%

fesc=10%

C=3

=480

=20

reionization history3
Reionization History

Haiman & Holder 2003

Sudden Transition from

a Metal Free to a Normal

Stellar Population

0.17

electron fraction

=8 for z<14

=160 for z>14

Wyithe & Loeb 2002

Cen 2002

redshift

wmap implications
WMAP implications

no ‘crisis’

  • Complex reionization history required by WMAP + SDSS
  • - significant activity at high redshift (“3” result)
  • either : metal-free stars, mini-quasars with x60 “boost”
  • or : H2 molecules form efficiently in Type II halos
  • Some cosmogonies can be ruled out
  • - dark age = test-bed of small-scale P(k)
  • - WDM (~3? keV), Mixed DM (?) (Barkana, Haiman, Ostriker)
  • - Running Index (requires x 50 boost and H2 formation)
  • or x 3000 boost (Haiman & Holder 2003)
  • Future promise
  • - WMAP is sensitive only to  (total electron column)
  • - But if ≳0.1, then future EE/TE can distinguish xe(z)
  • (Kaplinghat et al. 2002 ; Holder et al. 2003)
future polarization measurements
Future Polarization Measurements
  • Three reionization histories with same 0.16
  • Different polarization power spectra
  • >4 in cosmic variance limit, ~3 for Planck
  • Can induce bias in  measurement (up to~0.02)

Haiman &

Holder (2003)

xe

Redshift

looking for electrons in the cmb
Looking for Electrons in the CMB
  • CMB anisotropies
  • - damping of temperature anisotropy (geometrical)
  • - boosts large-angle polarization anisotropy (geom.)
  • - small scale SZ effect (energy)(l ≳ 3000; Oh et al. 2003)
  • Talks by M. Santos
  • and M. Kamionkowsky
  • Distortions of mean spectrum
  • - Compton heating: y=1/4 u/u ~ 10-5
  • if 10-4 of baryons in BHs, with 1% into heating
  • - dust scattering with 0.3 M⊙ dust per SN: y ~ 10-5
  • - improve FIRAS/COBE limit to 10-7 …(?)
  • (Fixsen & Mather 2002)
conclusions
Conclusions
  • LCDM cosmogony naturally accommodates reionization
  • Different populations to satisfy both SDSS QSO + WMAP
  • Either H2 formation or significant (x50) boost in efficiency
  • Future CMB observations will probe reionization history
  • Ly Emitters and 21cm will probe neutral hydrogen
  • JWST will make direct detections to z=10 and beyond

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