Formation et Evolution des Galaxies - Groupe de Recherche IAP

Date	Sujet	Présenté par
16 mai 2013	Why the high-redshift submillimetre galaxy population is more complicated than we thought Submillimetre galaxies (SMGs) -- which are some of the most luminous, rapidly star-forming galaxies in the Universe -- have long been thought to be predominantly merger-induced starbursts, i.e., 'scaled-up' analogues of local ultraluminous infrared galaxies. However, recent observational evidence and theoretical arguments suggest that the population is significantly more complicated than previously thought. I will present a revised model for the SMG population that is based on the results of a combination of dust radiative transfer performed on hydrodynamical simulations of disc galaxies and galaxy mergers and cosmological simulations. I will argue that although merger-induced starbursts contribute to the SMG population, other types of sources also contribute significantly. In particular, early-stage mergers, projected multiples in which one or more components are physically unrelated to the others, and isolated discs can all provide significant contributions, depending on the flux density considered. I will discuss recent observational evidence that favours our model and present predictions for follow-up observations of SMGs resolved by ALMA. Finally, I will argue that when all of the aforementioned subpopulations are accounted for, the submm number counts are consistent with a standard initial mass function, which is in contrast with some previous claims. MNRAS 2013 arXiv 2013	Chris Hayward Heidelberg Inst. Theoret. Stud., Allemagne

Résumé d'un journal-club