2 v 1 8 M ar 1 99 9 Far – infrared Point Sources

The analysis of the submm anisotropies that will be mapped by the forthcoming map and planck satellites requires careful foreground subtraction before measuring CMB fluctuations. Among these, the foreground due to IR/submm thermal radiation from dusty sources was poorly known until recent observational breakthroughs began unveiling the properties of these objects. We hereafter briefly review the observational evidence for a strong evolution of IR/submm sources with respect to the local universe explored by iras. We present the basic principles of a new modeling effort where consistent spectral energy distributions of galaxies are implemented into the paradigm of hierarchical clustering with the fashionable semi–analytic approach. This model provides us with specific predictions in IR/submm wavebands, that seem to reproduce the current status of the observations and help assessing the capabilities of forthcoming instruments to pursue the exploration of the deep universe at IR/submm wavelengths. Finally, the ability of the planck High Frequency Instrument all–sky survey to produce a catalogue of dusty sources at submm wavelengths is briefly described.