Dust emission in the diffuse interstellar medium from far-infrared to millimeter: new constraints from WMAP

The dust emission from far-infrared to millimeter is intensively used to trace the matter and the physical conditions in the Universe. The objective of studying the dust emission at these wavelengths in the DIFFUSE interstellar medium of the Galaxy is twofold. First, unlike in the galactic plane where several clouds overlap on the lines of sight, results are easier to interpret in term of physical properties of dust. Second, one of the major challenges in high sensitivity cosmic (microwave or submillimeter) background anisotropy study is to determine the fraction of the observed signal due to diffuse galactic foregrounds.

In this framework, and based on the new results from the WMAP mission, I propose to review our knowledge on the dust emission in the diffuse sky. Our current understanding is based on analysis of the COBE data combined with several templates of gas tracers (HI and Hα). In the millimeter, emphasis will be given to the new WMAP results on the so-called 'anomalous microwave emission' (e.g. Lagache, A&A 2003, in press). Finally, unanswered questions will be addressed in the prospect of the Herschel and Planck sub-millimetre/millimeter satellites.