Cosmological Parameter Extraction from the First Season of Observations with the Degree Angular Scale Interferometer

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Abstract
The Degree Angular Scale Interferometer (DASI) has measured the power spectrum of the cosmic microwave background anisotropy over the range of spherical harmonic multipoles 100 < l < 900. We compare these data, in combination with the COBE DMR results, to a seven-dimensional grid of adiabatic cold dark matter (CDM) models. Adopting the priors h > 0.45 and 0.0 ≤ τc ≤ 0.4, we find that the total density of the universe Ωtot = 1.04 ± 0.06 and the spectral index of the initial scalar fluctuations ns = 1.01 in accordance with the predictions of inflationary theory. In addition, we find that the physical density of baryons Ωbh2 = 0.022, and the physical density of cold dark matter Ωcdmh2 = 0.14 ± 0.04. This value of Ωbh2 is consistent with that derived from measurements of the primeval deuterium abundance combined with big bang nucleosynthesis theory. Using the result of the Hubble Space Telescope (HST) Key Project, h = 0.72 ± 0.08, we find that Ωtot = 1.00 ± 0.04, the matter density Ωm = 0.40 ± 0.15, and the vacuum energy density ΩΛ = 0.60 ± 0.15. (All 68% confidence limits.)