Cosmology with Cosmic Microwave Background Radiation

The main aim of this book is to study the Cosmological Principle, the basic assumption of cosmological standard model, through observations. The possible violation of global isotropy in the Cosmic Microwave Background has been a subject of intense research after the publication of WMAP data. The possible alignment of axes corresponding to several diverse data sets in the direction of the Virgo cluster makes this extremely interesting. In recent years, there have been a large number of studies which claim the CMB temperature fluctuations are not consistent with statistical isotropy and thus questioning the cosmological principle. Meanwhile there are some studies which also found no inconsistency. Differences arise due to different independent statistical methods that are designed to study deviations from statistical isotropy. The reason is that statistical isotropy can be violated in many different ways and each independent statistical method is more sensitive to a special kind of violation of statistical isotropy. It is, therefore, necessary to explore new observables to determine whether the CMB sky is a realization of statistically isotropic or not.