Planck CO revisited: Improved CO line emission maps from Planck space mission observations

Abstract

The Planck space mission has observed the first three rotational lines of emission of Galactic CO. Those maps, however, are either noisy, or contaminated by astrophysical emissions from different origin. We revisit those data products to deliver new full-sky CO maps with low astrophysical contamination and significantly enhanced noise properties. To that effect, a specific pipeline is designed to evaluate and postprocess the existing Planck Galactic CO maps. Specifically, we use an extension of the Generalized Needlet Internal Linear Combination method to extract multi-component astrophysical emissions from multi-frequency observations. Well characterized, clean CO full-sky maps at $10^\prime$ angular resolution are produced. These maps are made available to the scientific community and can be used to trace CO emission over the entire sky, and to generate sky simulations in preparation for future CMB observations.