The shape of the CMB power spectrum

Abstract

The recent WMAP data represents a milestone in cosmology and helps constrain cosmological parameters with unprecedented accuracy. In this work we combine the WMAP data with previous CMB anisotropy measurements at smaller angular scales to characterize the shape of the CMB anisotropy power spectrum. We carry out a phenomenological analysis of the data. By allowing non-physical shapes of the power spectrum we analyse high and low frequency experiments separately and together. We find that WMAP dramatically constrains the power spectrum up to l \~ 700. On smaller scales, the data show discrepancies that can be associated with experimental systematics. If we combine all types of experiments, the observable features in the power spectrum are in excellent agreement with the WMAP cosmological parameter estimation. This work illustrates the advantages of a model-independent approach to understanding experimental systematics that might affect CMB observations.