Cosmic microwave background temperature and polarization anisotropy in Brans-Dicke cosmology

Journal Article · Mon Nov 01 04:00:00 EST 1999 · Physical Review, D

DOI:https://doi.org/10.1103/PhysRevD.60.104036· OSTI ID:690765

Chen, X; Kamionkowski, M ^[1]

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1. Department of Physics, Columbia University, 538 West 120th Street, New York, New York 10027 (United States)

We develop a formalism for calculating cosmic microwave background (CMB) temperature and polarization anisotropies in cosmological models with Brans-Dicke gravity. We then modify publicly available Boltzmann codes to calculate numerically the temperature and polarization power spectra. Results are illustrated with a few representative models. Comparing with the general-relativistic model of the same cosmological parameters, both the amplitude and the width of the acoustic peaks are different in the Brans-Dicke models. We use a covariance-matrix calculation to investigate whether the effects of Brans-Dicke gravity are degenerate with those of variation in other cosmological parameters and to simultaneously determine whether forthcoming CMB maps might be able to distinguish Brans-Dicke and general-relativistic cosmology. Although the predicted power spectra for plausible Brans-Dicke models differ from those in general relativity only slightly, we find that MAP and/or the Planck Surveyor may in principle provide a test of Brans-Dicke theory that is competitive to solar-system tests. For example, if all other parameters except for the CMB normalization are fixed, a value of the Brans-Dicke parameter {omega} as large as 500 could be identified (at the 2{sigma} level) with MAP, and for Planck, values as large as {omega}{approx_equal}3000 could be identified; these sensitivities are decreased roughly by a factor of 3 if we marginalize over the baryon density, Hubble constant, spectral index, and re-ionization optical depth. In more general scalar-tensor theories, {omega} may evolve with time, and in this case, the CMB probe would be complementary to that from solar-system tests. {copyright} {ital 1999} {ital The American Physical Society}

• OSTI ID: 690765
• Journal Information: Physical Review, D, Journal Name: Physical Review, D Journal Issue: 10 Vol. 60; ISSN PRVDAQ; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
BACKGROUND RADIATION
COSMIC RADIATION
COSMOLOGICAL MODELS
COSMOLOGY
GRAVITATION
MICROWAVE RADIATION
POLARIZATION
TEMPERATURE DISTRIBUTION