UCSB South Pole 1994 CMB anisotropy measurement constraints on open and flat-Lambda CDM cosmogonies

Abstract

We develop methods to account for experimental and observational uncertainties in likelihood analyses of data from cosmic microwave background (CMB) anisotropy experiments and apply them to an analysis of the UCSB South Pole 1994 (SP94) experiment. Observationally motivated open and spatially-flat $\Lambda$, cold dark matter cosmogonies are considered. Among the models we consider, the full SP94 data set is most consistent with $\Omega_0 \sim 0.1-0.2$ open models and less so with old $(t_0 \gap 15 - 16 Gyr)$, high baryon density $(\Omega_B \gap 0.0175 h^{-2})$, low density ($\Omega_0 \sim 0.2 - 0.4), flat-$\Lambda$ models. The SP94 data do not rule out any of the models we consider at the $2\sigma$ level. The SP94 experiment is most sensitive to anisotropies on a somewhat larger, model-dependent, angular scale than the scale at which the window function peaks. For establishing the significance of a detection of CMB anisotropy we derive limits using the highest posterior density (HPD) prescription, since it yields smaller lower limits. Since HPD limits lead to tighter constraints on the CMB amplitude, they also provide for greater discrimination between models. Model normalizations deduced from the SP94 data subsets are mostly consistent with those deduced from the two-year COBE-DMR data, although the Ka-band data prefer a normalization $\sim 1\sigma$ lower than do the Q-band data, the Q and Ka + Q data favour a slightly higher normalization for the $\Omega_0 = 0.1$ open model than does the DMR, and the Ka and Ka + Q data prefer a somewhat lower normalization for the older, higher $\Omega_B$, low-density $\Lambda$ models than does the DMR.