Original Articles |
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Determining the Cosmic Equation of State from Gravitational Lensing |
ZHU Zong-hong;CAO Li |
Beijing Astronomical Observatory, Chinese Academy of Sciences, Beijing 100012
National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012
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Cite this article: |
ZHU Zong-hong, CAO Li 1999 Chin. Phys. Lett. 16 934-937 |
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Abstract An independent method is proposed to determine the equation of state, ωx ≡ px/ρx, for the dark energy component in the universe. This method is based on gravitational lensing statistics. An analytically simple expression for the optical depth of gravitational lensing in general Friedmann-Robertson- Walker cosmologies with dark energy component is derived. It is shown that for a flat universe the optical depth depends sensitively on the redshift to the source zs and the equation of state ωx which makes the method proposed here efficient and robust.
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Keywords:
98.80.Hw
98.62.Sb
98.80.Es
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Published: 01 December 1999
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PACS: |
98.80.Hw
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98.62.Sb
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(Gravitational lenses and luminous arcs)
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98.80.Es
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(Observational cosmology (including Hubble constant, distance scale, cosmological constant, early Universe, etc))
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Abstract
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