New computational approaches to analysis of CMB map: the statistical isotropy and gaussianity

摘要: The Wilkinson Microwave Anisotropy Probe (WMAP) mission is designed to determine the geometry, matter content, and the evolution of the universe. It is shown that the universe is geometrically flat and dark energy at the present time has the dominant contribution in the matter content of universe, causes the universe to accelerate rather than decelerate [1–4]. The statistical properties of the Cosmic Microwave Background radiation (CMB) data can be a unique tool to identify the the parameters of standard model of cosmology [5]. The results of WMAP are a milestone in CMB anisotropy measurements since it combines high angular resolution, high sensitivity, with ‘full’sky coverage allowed by a space mission. The frequency coverage of WMAP experiment allows CMB sky maps to be foreground cleaned up to l∼ 100 [4].After the first year of WMAP data, the statistical isotropy and Gaussianity of the CMB anisotropy have attracted considerable attention. Tantalizing evidence of statistical isotropy breakdown and non-Gaussianity have mounted in the WMAP first year sky maps, using a variety of different methods. Since the observed CMB sky is a single realization of the underlying correlation, the detection of statistical isotropy violation or correlation patterns pose a great observational challenge. In order to extract more information from the rich source of information provided by present (and future) CMB maps, it is important to design as many independent statistical methods as possible to study deviations from standard statistics, such as statistical isotropy. Since statistical isotropy can be violated in many different ways,