Massive Galaxies in Cosmological Simulations: Ultraviolet‐selected Sample at Redshiftz = 2

We study the properties of galaxies at z=2 in a Lambda CDM universe, using two different types of hydrodynamic simulation methods (Eulerian TVD and SPH) and a spectrophotometric analysis in the Un, G, R filter set. The simulated galaxies at z=2 satisfy the color-selection criteria proposed by Adelberger et al. (2004) when we assume Calzetti extinction with E(B-V)=0.15. We find that the number density of simulated galaxies brighter than R~1e11 Msun, and their observed-frame G-R colors lie in the range 0.0= 1.0 and Mstar>1e10 Msun/h finished the build-up of their stellar mass by z~3. Interestingly, our study suggests that the majority of the most massive galaxies at z=2 should be detectable at rest-frame UV wavelengths, contrary to some recent claims made on the basis of near-IR studies of galaxies at the same epoch, provided the median extinction is less than E(B-V)25.5) and intrinsically redder galaxies. Our results do not suggest that hierarchical galaxy formation fails to account for the massive galaxies at z>=1. (abridged)