Yanchuan%20Cai%20(???)

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Yanchuan Cai (???) Shaun Cole, Adrian Jenkins,
Carlos Frenk Institute for Computational
Cosmology Durham University
May 31, 2008, NDHU,
Taiwan
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Potential decay ISW effect

• Potential change induce
• secondary CMB
• temperature fluctuation

• Linear regime
• Integrated Sachs-Wolfe effect
• (ISW) (Sachs Wolfe 1967)

• Non-linear regime -
• Rees-Sciama effect (RS)
• (Rees Sciama 1968)
• ISW RS effect capture the
• dynamics of the universe

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Constraint of Dark energy
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Imprint on the CMB Power spectrum
Cooray 2002
Hu 2001
The ISW effect is difficult to be detected from
the CMB power spectrum due to cosmic
variance. The Rees-Sciama effect is negligible
for the CMB PS, but
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Cross-correlation of LSS CMB
b(t) Galaxy bias parameter N(t) Galaxy
selection function

• ISW fluctuations are correlated with galaxy
  distribution
• Galaxies are bias tracer to large scale structure

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Galaxy survey with CMB map
Sky covrerage 5.55.5 deg2, Survey Depth
mean z0.15
Fosalba Gaztanag 2004
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Cabre et al. 2006
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ISW Tomography Dark Energy Evolution

• Deep galaxy survey
• detection of the
• evolution of dark energy
• Large sky coverage
• improving S/N

Cai et al. in preparation Hu Scranton 2004
LoVerde et al. 2007
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You may expect more than ISW
ISW Rees-Sciama SZ Lensing Doppler
redshift
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Sunyaev-Zeldovich effect
tSZ
Moving halo effect
Lensing magnification
Doppler effect
LOS
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Rees-Sciama effect
SZ effect
Seljak 1995 Afshordi et al. 2004 Fosalba
Gaztanag 2004 LoVerde et al. 2007
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• Power spectra of the
• potential derivative
• measured from the
• L-BASICC simulation.
• The second order
• contribution can be
• well modeled by a
• broken power law.
• Deviation of the
• total power spectrum
• from linear theory
• occurs at larger
• scales as redshift
• Increase.

Cai et al. in prep.
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• 2-D Power spectra of
• the potential derivative
• measured from the
• L-BASICC simulation.
• L-BASICC simulation is the LambdaCDM
• cosmology with
• Deviation of the
• total power spectrum
• from linear theory
• occurs at larger scales
• as redshift increase.

Cai et al. in prep.
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ISW RS
ISW
ISW cross-correlation
Cai et al. in prep.
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ISW RS
ISW
ISW cross-correlation
Cai et al. in prep.
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Summary

• Cross-correlation of LSS CMB provides
  constraint to dark energy
• ISW tomography is promising, but hard
• Separating ISW, SZ, lensing magnification,
  Doppler effect, Rees-Sciama effect
• RS effect dominates at high-z, could be important
  on the scale of a few degrees
• Accurate modeling of the RS effect would be useful