"Nonparametric Inference for the Cosmic Microwave Background." Statist. Our analysis shows that, even without parametric assumptions, the first peak is resolved accurately with current data but that the second and third peaks are not. We apply these techniques to test various models and to extract confidence intervals on cosmological parameters of interest. The CMB (Cosmic Microwave Background) essentially is constituted by the photons of the time when matter and radiation was in equilibrium. Our estimated spectrum, based on minimal assumptions, closely matches the model-based estimates used by cosmologists, but we can make a wide range of additional inferences. We use recently developed techniques to construct a nonparametric confidence set for the unknown CMB spectrum. Thus, a critical statistical question is how accurately can these peaks be estimated. The spectrum’s shape, and in particular the location and height of its peaks, relates directly to the parameters in the cosmological models. The discovery of cosmic microwave background radiation constitutes a major development in modern physical cosmology.In 1964, US physicist Arno Allan Penzias and radio-astronomer Robert Woodrow Wilson discovered the CMB, estimating its temperature as 3.5 K, as they experimented with the Holmdel Horn Antenna. To this end, cosmologists usually summarize the fluctuations by the power spectrum, which gives the variance as a function of angular frequency. For example, CMB data can be used to determine what portion of the Universe is composed of ordinary matter versus the mysterious dark matter and dark energy.
Recent observations, from the Cosmic Microwave Background Explorer to the Wilkinson Microwave Anisotropy Probe, have strikingly confirmed this prediction.ĬMB fluctuations provide clues to the Universe’s structure and composition shortly after the Big Bang that are critical for testing cosmological models. On very large scales, the CMB radiation field is smooth and isotropic, but the existence of structure in the Universe-stars, galaxies, clusters of galaxies, …-suggests that the field should fluctuate on smaller scales. The cosmic microwave background (CMB), which permeates the entire Universe, is the radiation left over from just 380,000 years after the Big Bang.
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