Recent results

Our knowledge of the CMB power spectrum has been significantly improved since COBE measurements [5] by two balloon-borne experiments, BOOMERanG [9] and MAXIMA [10], and a ground based interferometric experiment, DASI [12]. These results are shown in Figure . We observe that the very low part of the power spectrum is highly constrained by the COBE points while the high-$\ell$ acoustic region is constrained by the three recent experiments showing undoubtly the multiple peak feature that is expected from inflation. This set of data therefore strongly disfavors topological defects as seeds for the structure formation in the Universe. Comparing this set of data with theoretical power spectra have lead to the estimation of the cosmological parameters [9,11,14]. The favored model is dominated by dark energy (around 70%) such as cosmological constant or quint essence (in agreement with high redshift type Ia supernovae measurements [15,16]). The 30% of matter consists mainly of dark matter and the amount of baryons is in agreement with Big-Bang nucleosynthesis predictions and light elements abundances measurements. One of the great news coming from these results is that they agree very well with other measurements of the cosmological parameters obtained with completely different methods: large scale structure observation, lensing, type Ia supernovae and light elements abundances. We are now heading towards a concordance model.