The role of the LIRG and ULIRG phases in the evolution of K-selected galaxies

¹ Institut d'Astrophysique Spatiale (IAS), bâtiment 121, Université Paris-Sud 11 and CNRS (UMR 8617), 91405 Orsay, France e-mail: [kcaputi;herve.dole;guilaine.lagache;puget]@ias.u-psud.fr
² Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, EH9 3HJ, Edinburgh, UK e-mail: [rjm;jsd]@roe.ac.uk
³ Steward Observatory, University of Arizona, 933 N Cherry Ave, Tucson, AZ 85721, USA e-mail: [elefloch;pgperez]@as.arizona.edu
⁴ Also associated to the Observatoire de Paris, GEPI, 92195, Meudon, France

Received: 21 November 2005
Accepted: 10 April 2006

Abstract

Aims.We investigate the role of the luminous infrared galaxy (LIRG) and ultra-luminous infrared galaxy (ULIRG) phases in the evolution of K_s-selected galaxies and, in particular, Extremely Red Galaxies (ERGs).

Methods.With this aim, we compare the properties of a sample of 2905 (Vega mag) galaxies in the GOODS/CDFS with the sub-sample of those 696 sources which are detected at .

Results.We find that LIRGs constitute 30% of the galaxies with stellar mass assembled at redshift . A minimum of 65% of the galaxies with at are ULIRGs at those redshifts. 60% of the ULIRGs in our sample have the characteristic colours of ERGs. Conversely, 40% of the ERGs with stellar mass at and a minimum of 52% of those with the same mass cut at are ULIRGs. The average optical/near-IR properties of the massive ERGs at similar redshifts that are identified with ULIRGs and that are not have basically no difference, suggesting that both populations contain the same kind of objects in different phases of their lives.

Conclusions.LIRGs and ULIRGs have an important role in galaxy evolution and mass assembly, and, although they are only able to trace a fraction of the massive () galaxies present in the Universe at a given time, this fraction becomes very significant (%) at redshifts .