All-sky component separation for the Planck mission

An 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 a maximum multipole of around 6000. The simulated Planck data include emission from the 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 a multipole of around 2000. The algorithm is parallelised so that the entire reconstruction can be performed in around 6 hr using 30 R10000 processors on an SGI Origin 2000 supercomputer and requires 14 Gb of memory.