In order to avoid duplicating efforts, the various sub-groups of WG2 which are devoted to providing information on specific sky components relevant to our purposes are in common with Working groups devoted to the science relative to that component.

In practice, we have the following identities:

 WG 2.3 = WG 6.2: Ancillary extragalactic catalogs & techniques
 WG 2.4 = WG 7.2: Ancillary Galactic data & techniques
 WG 2.5 = WG 4.2: Simulations of non-Gaussian models
 WG 2.6 = WG 5.5: Simulations of clusters, LSS & other Secondary effects
 WG 2.7 = WG 6.5: Simulations of compact sources & associated background
 WG 2.8 = WG 7.3: Simulations of the diffuse interstellar emission
 WG 2.9 = WG 7.7: Moving objects extraction and separation