On Breaking Cosmic Degeneracy

Abstract

It has been argued that the power spectrum of the anisotropies in the Cosmic Microwave Background (CMB) may be effectively degenerate, namely that the observable spectrum does not determine a unique set of cosmological parameters. We describe the physical origin of this degeneracy and show that at small angular scales it is broken by gravitational lensing: effectively degenerate spectra become distinguishable at l ~ 3000 because lensing causes their damping tails to fall at different rates with increasing l. This effect also helps in distinguishing nearly degenerate power spectra such as those of mixed dark matter models. Forthcoming interferometer experiments should provide the means of measuringotherwise degenerate parameters at the 5-25% level.

7 pages, LaTeX, two figures, to be published in ApJ Letters

References in corpus (2)

• Microwave Background Constraints on Cosmological Parameters
• Gravitational Magnification of the Cosmic Microwave Background

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• Cosmic Confusion: Degeneracies among Cosmological Parameters Derived from Measurements of Microwave Background Anisotropies
• Determining Neutrino Mass from the CMB Alone
• Reconstructing Projected Matter Density from Cosmic Microwave Background
• General Relativity and Cosmology: Unsolved Questions and Future Directions
• The influence of non-uniform reionization on the CMB
• Lensing of the CMB: Non Gaussian aspects
• ALMA observations of massive molecular gas filaments encasing radio bubbles in the Phoenix cluster
• Gravitational lensing of cosmic microwave background anisotropies and cosmological parameter estimation
• The Cosmic Microwave Background Radiation
• Non-Gaussian structure of the lensed CMB power spectra covariance matrix
• Contributions to the Power Spectrum of Cosmic Microwave Background from Fluctuations Caused by Clusters of Galaxies
• Rapid Calculation of Theoretical CMB Angular Power Spectra
• Lensing effect on polarization in microwave background: extracting convergence power spectrum
• Constraints in Cosmological Parameter Space from the Sunyaev-Zel'dovich Effect and Thermal Bremsstrahlung
• Lensing effect on the relative orientation between the Cosmic Microwave Background ellipticities and the distant galaxies
• Breaking the cosmological background degeneracy by two-fluid perturbations in f(R) gravity
• Gravitational Lensing Effect on the Two-point Correlation of Hotspots in the Cosmic Microwave Background
• Reconstructing the Gravitational Lensing Potential from the Lyman-$\alpha$ Forest
• Implications of a holographic density of states on inflation
• Weak Lensing the non-Linear Ly-alpha Forest