No evidence for the evolution of mass density power-law index γ from strong gravitational lensing observation

In this paper,we consider the singular isothermal sphere lensing model that has a spherically symmetric power-law mass distributionρ_(tot)(r)～r^(-γ).We investigate whether the mass density power-law indexγis cosmologically evolutionary by using the strong gravitational lensing(SGL)observation,in combination with other cosmological observations.We also check whether the constraint result ofγis affected by the cosmological model,by considering several simple dynamical dark energy models.We find that the constraint onγis mainly decided by the SGL observation and independent of the cosmological model,and we find no evidence for the evolution ofγfrom the SGL observation.

In this paper, we consider the singular isothermal sphere lensing model that has a spherically symmetric power-law mass dis- tribution ρtot（r） - r-γ. We investigate whether the mass density power-law index y is cosmologically evolutionary by using the strong gravitational lensing （SGL） observation, in combination with other cosmological observations. We also check whether the constraint result of y is affected by the cosmological model, by considering several simple dynamical dark energy models. We find that the constraint on y is mainly decided by the SGL observation and independent of the cosmological model, and we find no evidence for the evolution of y from the SGL observation.