Presentation 1 : Oral
Empirical modelling of the infrared galaxy evolution (PNC)
G. Lagache, H. Dole, J.-L. Puget
To understand the nature of the sources contributing to the extragalactic background and to interpret the deep source counts,
we have developped a phenomenological model. It constrains in a
simple way the galaxy luminosity function evolution with the redshift, and fits all the existing source counts, redshift distribution, and the observations of the Cosmic Infrared Background intensity and for the first time its fluctuations, from the mid-infrared to the submillimetre range. Although the Cosmic Infrared Background can be modeled with very different luminosity functions as long as the radiation production with redshift is the right one, the number counts, and the anisotropies of the unresolved background, imply that the luminosity function must change dramatically with redshift, the evolution rate being much higher than in other wavebands.
The model is intended as a convenient tool to plan further observations,
as illustrated through predictions for Planck, Herschel and ALMA observations.