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
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
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.
ZHU Zong-hong;CAO Li. Determining the Cosmic Equation of State from Gravitational Lensing[J]. 中国物理快报, 1999, 16(12): 934-937.
ZHU Zong-hong, CAO Li. Determining the Cosmic Equation of State from Gravitational Lensing. Chin. Phys. Lett., 1999, 16(12): 934-937.
1999, Vol. 16 
