Andrea Ferrara

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ALMA Views of Reionization

• Andrea Ferrara

SISSA/International School for Advanced Studies,
Trieste
2
Reionization Tests
Reionization at a Glance
Redshift
Neutral IGM
.
z ? zi
z lt zi
z gt zi
Wavelength
Wavelength
Wavelength
Lyman Forest Absorption
Black Gunn-Peterson trough
Patchy Absorption
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Reionization Tests
WMAP results reionization at z gt 10 ?
Temperature-Polarization Cross Power Spectrum
te 0.17 0.04
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Modelling Reionization
Ciardi, AF, White 2003
Reionization after WMAP
z 17.6 z15.5
z13.7
Larson IMF Salpeter IMF
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Does early reionization agree with data ?
Ionized regions filling factor
Mean density temperature
LLS statistics
log
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Inhomogeneous Reionization
Salvaterra, Ciardi, AF Baccigalupi 2005
More than ?e CMB secondary anisotropies
? 1 arcmin
ALMA 1h
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Inhomogeneous Reionization
Salvaterra, Ciardi, AF Baccigalupi 2005
Additional hints from CMB21cm line
CROSS CORRELATE
115 MHz
90 MHz
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Inhomogeneous Reionization
Salvaterra, Ciardi, AF Baccigalupi 2005
HII regions size evolution
Size of HII region (Mpc) from zero of correlation
fct.
early
late
Bandwidth
9

• Want to know more ?

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• THE END

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Imprint of First Stars on IR Background
Magliocchetti, Salvaterra AF 2003
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Light from First Galaxies
Ciardi, AF White 2003
Reionization after WMAP
A Conservative Model No exotica

• Maximum H2/UV feedback no stars in minihalos
• Smallest star-forming halos M 5108 MO
• Moderately heavy IMF Larson, Mc 5 MO
• No Very Massive Stars, but metal-free
• Maximum Escape Fraction, fesc 20

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Reionization Tests
Gunn-Peterson Test Reionization at z 6 ?
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First Light at Cosmic Dawn Very Massive Stars
Salvaterra AF 2002
Magliocchetti, Salvaterra AF 2003
IR Background Data Points
Best fit model to NIR data zend 8.8 f? ? 30
PopIII StarsGalaxies
Galaxies
Pop III stars can explain observed NIRB
excess if VMS dominate IMF
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Reionization by Very Massive Stars ?
z 17
NIRB - fitting evolution
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Inhomogeneous Reionization
Choudhury AF 2005

• Self-consistent treatment of the evolution of
  ionized regions and thermal history

• Follow evolution of neutral, HII and HeIII
  regions treat IGM as multiphase gas

• Inhomogeneous density distribution log-normal
  model

• Three sources of ionizing radiation
• ? PopIII stars early redshifts, high mass,
  zero metallicity
• ? PopII stars Salpeter IMF, transition from
  PopIII _at_ z lt 9
• ? Quasars significant _at_ z lt 6, using ?-MBH
  relation

• Radiative feedback suppressing SF in low-mass
  halos, set by
• ? Molecular cooling in neutral regions
• ? Photoionization temperature in ionized
  regions

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Light from First Galaxies
Optical Depth Evolution
Reconciling with GP-effect requires a subsequent
drop of the ionizing power
No contribution to optical depth in 6 ltz lt 9
still within WMAP error box
L20