Galaxies 09: Assembly, Gas Content and Star Formation History of Galaxies

Alexandra Pope
NOAO

New observational constraints on the sources of the cosmic infrared background

We present new observational constraints on the sources of the cosmic infrared background (CIB) from 70-500 microns. We perform a careful stacking analysis to determine the contribution of mid-IR (Spitzer/MIPS) selected galaxies to the background. Our stacking analysis is backed by detailed simulations which predict the fraction of the background resolved by a given population. We find that half of the CIB is still unresolved at submillimeter wavelengths - this fraction of the background must therefore be coming from luminous infrared galaxies (LIRGs) or sub-LIRGs at $z>1$. We discuss the implications of this on the cosmic star formation rate density. Future extragalactic surveys with Herschel will get closer to resolving all the background but it will not be until ALMA that we are able to individually detect LIRGs at $z>1$ in the submillimeter and thus provide a complete census of the redshift and luminosity distribution of the sources of the CIB.

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