Abstract : The analysis of cosmic microwave background anisotropies in both temperature and polarisation allows one to constrain the cosmological parameters that describe the Big-Bang model and the early Universe. This thesis is focused on the measurements obtained with the Archeops balloon borne experiment as well as on the future space mission Planck for which Archeops is a test-bench.
After a general description of the standard cosmological model and of the CMB physics, this thesis deals more precisely with the reheating mechanism that produces matter at the end of inflation.
The next part presents the Archeops and Planck experiments and their data analysis. I have developed various methods designed to study parasitic signals by cosmic rays, to evaluate the bolometer time response and to take into account the asymmetry of the optical beam.
The CMB fluctuations analysis is performed by estimating the power spectra in both temperature and polarisation. For this purpose, I present a method that provides a fast unbiased estimation of the power spectra as well as analytic error bars not relying on Monte Carlo simulations. This method has been used to obtain the latest estimate of the Archeops CMB temperature power spectrum.
Finally, the last part deals with the implications of the Archeops results for WMAP and Planck. A joint Archeops-WMAP analysis shows the consistency of the CMB measurements through a large frequency range and allows for the detection of the Sunyaev-Zel'dovich effect. In addition, the extrapolation of the Galactic dust polarised power spectra is used as a reference for Planck.