Narrow Results

In this paper, we propose a new method to use the strong lensing data sets to constrain a cosmological model. By taking the ratio as cosmic observations, one can completely eliminate the uncertainty caused by the relation σ_SIS = f_Eσ₀ which characterizes the relation between the stellar velocity dispersion σ₀ and the velocity dispersion σ_SIS. Via our method, a relative tight constraint to the cosmological model space can be obtained, for the spatially flat ΛCDM model as an example in 3σ regions. And by using this method, one can also probe the nature of dark energy and the spatial curvature of our Universe.

Gravitational lensing is a unique and direct probe of mass in the universe. It depends only on the law of gravity and does not depend on the dynamical state nor the composition of matter. Thus, it is used to study the distribution of the dark matter in the lensing object. Combined with the traditional observations such as optical and X-ray, it gives us useful informations of the structure formation in the universe. The lensing observables depend also on the global geometry as well as large scale structure of the universe. Therefore it is possible to withdraw useful constraints on the cosmological parameters once the distribution of lensing mass is accurately known. Since the first discovery of the lensing event by a galaxy in 1979, various kinds of lensing phenomena caused by star, galaxy, cluster of galaxies and large scale structure have been observed and are used to study mass distribution in various scales and cosmology. Thus, the gravitational lensing is now regarded as an indispensable research field in the observational cosmology. In this paper, we give an instructive introduction to gravitational lensing and its applications to cosmology.

Gravitational lensing is a unique and direct probe of mass in the universe. It depends only on the law of gravity and does not depend on the dynamical state nor the composition of matter. Thus it is used to study the distribution of the dark matter in the lensing object. Combined with the traditional observations such as optical and X-ray, it gives us useful information on the structure formation in the universe. The lensing observables depend also on the global geometry as well as on the large scale structure of the universe. Therefore it is possible to derive useful constraints on cosmological parameters once the distribution of lensing mass is accurately known. Since the first discovery of a lensing event by a galaxy in 1979, various kinds of lensing phenomena caused by stars, galaxies, clusters of galaxies and large scale structure have been observed and are used to study the mass distribution at various scales and cosmology. Gravitational lensing is now regarded as an indispensable research tool in observational cosmology. In this article we give a pedagogical introduction to gravitational lensing and its applications to cosmology.