Characterizing the Peak in the CMB Angular Power Spectrum

Abstract

A peak has been unambiguously detected in the cosmic microwave background (CMB) angular spectrum. Here we characterize its properties with fits to phenomenological models. We find that the TOCO and BOOM/NA data determine the peak location to be in the range 175--243 and 151--259 respectively (both ranges 95% confidence) and determine the peak amplitude to be between ~70 and 90 micro Kelvin. By combining all the data, we constrain the full-width at half-maximum to be between 180 and 250 at 95% confidence. Such a peak is consistent with inflation-inspired flat, cold dark matter plus cosmological constant models of structure formation with adiabatic, nearly scale-invariant initial conditions. It is inconsistent with open and defect models.