Estimates of Cosmological Parameters Using the Cosmic Microwave Background Angular Power Spectrum of ACBAR

We report an investigation of cosmological parameters based on the measurements of anisotropy in the cosmic microwave background radiation (CMB) made by the Arcminute Cosmology Bolometer Array Receiver (ACBAR). We use the ACBAR data in concert with other recent CMB measurements to derive Bayesian estimates of parameters in inflation-motivated adiabatic cold dark matter models. We apply a series of additional cosmological constraints on the shape and amplitude of the density power spectrum and the Hubble parameter and from supernovae to further refine our parameter estimates. Previous estimates of parameters are confirmed, with sensitive measurements of the power spectrum now ranging from l ~ 3 to 2800. Comparing individual best-fit models, we find that the addition of Ω_Λ as a parameter dramatically improves the fits. We also use the high-l data of ACBAR, along with similar data from the Cosmic Background Imager and Berkeley-Illinois-Maryland Association array, to investigate potential secondary anisotropies from the Sunyaev-Zel'dovich effect. We show that the results from the three experiments are consistent under this interpretation and use the data, combined and individually, to estimate σ₈ from the Sunyaev-Zel'dovich component.