CMB anisotropy constraints on flat-λ and open CDM cosmogonies from DMR, UCSB south pole, python, AGRO, MAX, white dish, OVRO, and SuZIE data

Abstract

We use joint likelihood analyses of combinations of fifteen cosmic microwave background (CMB) anisotropy data sets from the DMR, UCSB South Pole 1994, Python I–III, ARGO, MAX 4 and 5, White Dish, OVRO, and SuZIE experiments to constrain cosmogonies. We consider open and spatially-flat-Λ cold dark matter cosmogonies, with nonrelativistic-mass density parameter Ω₀ in the range 0.1–1, baryonic-mass density parameter Ω_B in the range (0.005–0.029)h-2, and age of the universe t₀ in the range (10–20) Gyr. Marginalizing over all parameters but Ω₀, the data favor Ω₀ ≃ 0.9–1 (0.4–0.6) flat-Λ (open) models. The range in deduced Ω₀ values is partially a consequence of the different combinations of smaller-angular-scale CMB anisotropy data sets used in the analyses, but more significantly a consequence of whether the DMR quadrupole moment is accounted for or ignored in the analysis. While the open model is difficult to reconcile with the results of analyses of more recent CMB anisotropy data, the lower values of Ω₀ found in this case are more easily reconciled with dynamical estimates of this parameter. For both flat-Λ and open models, after marginalizing over all other parameters, a lower Ω_Bh² ≃ 0.005–0.009 is favored. This is also marginally at odds with estimates from more recent CMB anisotropy data and some estimates from standard nucleosynthesis theory and observed light element abundances. For both sets of models a younger universe with t₀ ≃ 12–15 Gyr is favored, consistent with other recent non-CMB indicators. We emphasize that we have performed an exact analysis (i.e. from data to parameter likelihoods without the intermediate step of data compression into band powers), and since we consider only a small number of data sets, these results are tentative. More importantly, the analyses here do not rule out the currently favored flat-Λ model with Ω₀ ~ 0.3, nor the larger Ω_Bh² values favored by some other data.