Combining maximum-entropy and the Mexican hat wavelet to reconstruct the microwave sky

We present a maximum-entropy method (MEM) and ‘Mexican hat’ wavelet (MHW) joint analysis to recover the different components of the microwave sky from simulated observations by the ESA Planck Surveyor satellite in a small patch of the sky . This combined method allows one to improve the CMB, Sunyaev–Zel'dovich and Galactic foregrounds separation achieved by the MEM technique alone. In particular, the reconstructed CMB map is free from any bright point-source contamination. The joint analysis also produces point-source catalogues at each Planck frequency that are more complete and accurate than those obtained by either method on its own. The results are especially improved at high frequencies where infrared galaxies dominate the point-source contribution. Although this joint technique has been performed on simulated Planck data, it could easily be applied to other multifrequency CMB experiments, such as the forthcoming NASA MAP satellite or the recently-performed BOOMERANG and MAXIMA experiments.