All-sky component separation for the Planck mission

A harmonic-space maximum-entropy method (MEM) is presented for separating the emission from different physical components in all-sky observations by the forthcoming Planck satellite. The analysis is performed at full Planck resolution, with a pixel size of 1.7 arcmin, which corresponds to l_max~ 6000. The simulated Planck data include emission from the cosmic microwave background (CMB), the kinetic and thermal Sunyaev-Zel'dovich (SZ) effects from galaxy clusters, as well as Galactic dust, free-free and synchrotron emission. Our simulations also assume homogeneous, uncorrelated pixel noise, although this is not a requirement of the method. We find that the MEM technique produces faithful reconstructions of the main input components over the whole sky, without the need to perform a Galactic cut. The CMB power spectrum is accurately recovered up to l~ 2000. The algorithm is parallelized so that the entire reconstruction can be performed in ~6 h using 30 R10000 processors on an SGI Origin 2000 supercomputer and requires 14 Gb of RAM.