Lookback time and Chandra constrains on cosmological parameters

摘要

In this paper we combine the WMAP7 with lookback time and Chandra gas fractiondata to constrain the main cosmological parameters and the equation of state for the dark energy. Wefind that the lookback time is a good measurement that can improve the determination of the equationof state for the dark energy with regard to other external data sets. We conclude that larger lookbacktime data set will further improve our determination of the cosmological parameters.