Cosmological implications of the MAXIMA-1 high-resolution cosmic microwavebackground anisotropy measurement

We discuss the cosmological implications of the new constraints on the powe r spectrum of the cosmic microwave background (CMB) anisotropy derived from a new high-resolution analysis of the MAXIMA-1 measurement. The power spec trum indicates excess power at l similar to 860 over the average level of p ower at 411 less than or equal to l less than or equal to 785. This excess is statistically significant at the similar to 95% confidence level. Its po sition coincides with that of the third acoustic peak, as predicted by gene ric inflationary models selected to fit the first acoustic peak as observed in the data. The height of the excess power agrees with the predictions of a family of inflationary models with cosmological parameters that are fixe d to fit the CMB data previously provided by BOOMERANG-LDB and MAXIMA-1 exp eriments. Our results therefore lend support for inflationary models and mo re generally for the dominance of adiabatic coherent perturbations in the s tructure formation of the universe. At the same time, they seem to disfavor a large variety of the nonstandard (but inflation-based) models that have been proposed to improve the quality of fits to the CMB data and the consis tency with other cosmological observables. Within standard inflationary mod els, our results combined with the COBE/Differential Microwave Radiometer d ata give best-fit values and 95% confidence limits for the baryon density, Omega (b)h(2) similar or equal to 0.033 +/- 0.013, and the total density, O mega = 0.9(-0.16)(+0.18). The primordial spectrum slope (n(s)) and the opti cal depth to the last scattering surface (tau (c)) are found to be degenera te and to obey the relation n(s) similar or equal to (0.99 +/- 0.14) + 0.46 tau (c), for tau (c) less than or equal to 0.5 (all at 95% confidence leve ls).