On the buildup of massive early-type galaxies at<i>z</i>$\la$ 1

Abstract

Context. Several studies have tried to ascertain whether the increase in abundance of the early-type galaxies (E-S0a's) with time is mainly due to major mergers, but have reached opposite conclusions. Aims. We have tested it directly through semi-analytical modelling, quantifying the possible contribution of the observed major mergers to the evolution of the high-mass end of the galaxy luminosity function (LF). Methods. The model analyses the backwards-in-time evolution of the massive early-type galaxies with log(M * /M ) > 11 at z 0 (mETGs) under the hypothesis that each major merger leads to an early-type galaxy. The model considers only the major mergers strictly reported by observations at each redshift and assumes that gas-rich major mergers experience transitory phases as dustreddened, star-forming galaxies (DSFs).