Non-Gaussian Distribution and Clustering of Hot and Cold Pixels in the WMAP Five-Year Sky - Astrophysics > Cosmology and Nongalactic AstrophysicsReportar como inadecuado




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Abstract: We present measurements of the clustering of hot and cold patches in themicrowave background sky as measured from the Wilkinson Microwave AnisotropyProbe WMAP five-year data. These measurements are compared with theoreticalpredictions which assume that the cosmological signal obeys Gaussianstatistics. We find significant differences from the simplest Gaussian-basedprediction. However, the measurements are sensitive to the fact that the noiseis spatially inhomogeneous e.g., because different parts of the sky wereobserved for different lengths of time. We show how to account for thisspatial inhomogeneity when making predictions. Differences from theGaussian-based expectation remain even after this more careful accounting ofthe noise. In particular, we note that hot and cold pixels cluster differentlywithin the same temperature thresholds at few-degree scales. While thesefindings may indicate primordial non-Gaussianity, we discuss other plausibleexplanations for these discrepancies. In addition, we find some deviations fromGaussianity at sub-degree scales, especially in the W band, whose origin may beassociated with extragalactic dust emission.



Autor: Graziano Rossi, Ravi K. Sheth, Changbom Park, Carlos Hernandez-Monteagudo

Fuente: https://arxiv.org/







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