Principal-component analysis of the cosmic microwave background anisotropies: revealing the tensor degeneracy |
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Authors: | G. Efstathiou |
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Affiliation: | Institute of Astronomy, Madingley Road, Cambridge CB3 0HA; Theoretical Astrophysics, Caltech, Pasadena, CA 91125, USA |
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Abstract: | A principal-component analysis of cosmic microwave background (CMB) anisotropy measurements is used to investigate degeneracies among cosmological parameters. The results show that a degeneracy with tensor modes – the 'tensor degeneracy'– dominates uncertainties in estimates of the baryon and cold dark matter densities, ω b=Ωb h 2 , ω c=Ωc h 2 , 1 from an analysis of CMB anisotropies alone. The principal-component analysis agrees well with a maximum-likelihood analysis of the observations, identifying the main degeneracy directions and providing an impression of the effective dimensionality of the parameter space. |
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Keywords: | cosmic microwave background cosmology: miscellaneous |
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