Cosmographic analysis from distance indicator and dynamical redshift drift

分类： 物理学 >> 核物理学 提交时间： 2016-08-30

Ming-Jian Zhang Hong Li Jun-Qing Xia

摘要： Cosmography is a model-independent de 1. To ensure data in the convergence radius, y=z/(1+z) redshift was defined. However, discussions about the usefulness of y-redshift and the leading cause of the issue are commonly absent. In the present paper, we study the cosmography in both z and y redshift using the supernova and mock redshift drift data. By introducing the bias-variance tradeoff, we reveal that the large bias square between cosmography and Union2.1 supernova data is the "chief culprit" of convergence issue. Moreover, expansion up to higher order and introduction of the y-redshift both are not effective to reconcile this contradiction. Minimizing risk, it suggests that Taylor expansion up to the second term is a better choice for available supernova data. Forecast from future supernova data and redshift drift shows that redshift drift can give much tighter constraints on the cosmography. We also investigate the effect of convergence issue on the deceleration parameter and dark energy. It inspires us that dynamical observations including redshift drift can give more detailed information on cosmic evolution

同行评议状态:待评议

 点击量 1897  下载量 944  评论