Sino-French workshop on the Dark Universe Strong lensing and dark energy

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Sino-French workshop on the Dark Universe
Strong lensing and dark energy

• Chen, Da Ming
• (CDM)
• National Astronomical Observatories,CAS
• Marseille, September 19-23,  2005

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Outline

• Introduction
• Dark energy
• Strong gravitational lensing
• Statistics of strong gravitational lensing
• Observational data
• Conclusions

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Introduction

• The properties of dark energy can be investigated
  by the observations of SN, CMB, and X-ray
• Another approach is gravitational lensing weak
  and strong
• Statistics of strong lensing this talk

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Dark energy

• All of the consequences of dark energy follow
  from its effects on the expansion rate (e.g.,
  Huterer Turner 2001, prd, 64, 123527)

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Dark energy

• Cosmic distance
• Proper distance
• Angular diameter distance

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Dark energy

• Matter density

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Strong gravitational lensing
DLS
b q - a
Lens equation
DS
qDS
aDLS
a
q
bDS
b
DS
DLS
DL
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Lensing equations

• GNFW
• SIS

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Lensing equations

• NTIS
• CIS

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Lensing equation curves
ycr
ycr
x0
Cross section
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Statistics of strong lensing
Statistics of strong lensing
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Observation data
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Some results

• Sarbu, Rusin
• Ma (2001, ApJ,
• 561,L147)

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Uncertainties

• The previous results assumed a flat universe, as
  assumed in this talk.
• Uncertainties arise from , Zs, and
• Flux ratio
• Magnification bias, cross section

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The effect of the limited flux ratio on cross
section

• Chen (2004,
• AA, 418, 387)

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The effect of the limited flux ratio on final
results

• Chen (2004,
• AA, 418, 387)

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Conclusions

• Statistics of strong lensing is an independent
  and powerful tool to determine the properties of
  dark energy.
• It is in agreement with the results from other
  approaches.

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• MERCI !