Foreground component separation with generalized Internal Linear Combination

Authors


E-mail: remazeil@apc.univ-paris7.fr (MR); delabrouille@apc.univ-paris7.fr (JD); cardoso@enst.fr (J-FC)

ABSTRACT

The ‘Internal Linear Combination’ (ILC) component separation method has been extensively used to extract a single component, the cosmic microwave background (CMB), from the WMAP multifrequency data. We generalize the ILC approach for separating other millimetre astrophysical emissions. We construct in particular a multidimensional ILC filter, which can be used, for instance, to estimate the diffuse emission of a complex component originating from multiple correlated emissions, such as the total emission of the Galactic interstellar medium. The performance of such generalized ILC methods, implemented on a needlet frame, is tested on simulations of Planck mission observations, for which we successfully reconstruct a low-noise estimate of emission from astrophysical foregrounds with vanishing CMB and Sunyaev–Zel’dovich contamination.

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