The varied fates of z ∼ 2 star-forming galaxies

Star-forming galaxies constitute the majority of galaxies with stellar masses greater than or similar to 10(10) h(-2) M-circle dot at z similar to 2. It is thus critical to understand their origins, evolution, and connection to the underlying dark matter distribution. To this end, we identify the dark matter halos ( including subhalos) that are likely to contain star-forming galaxies at z similar to 2 (z2SFGs)within a large dissipationless cosmological simulation and then use halo merger histories to follow the evolution of z2SFG descendants to z similar to 1 and z similar to 0. The evolved halos at these epochs are then confronted with an array of observational data in order to uncover the likely descendants of z2SFGs. Although the evolved halos have clustering strengths comparable to red galaxies at z similar to 1 and z similar to 0, we find that the bulk of z2SFGs do not evolve into red galaxies, at either epoch. This conclusion is based primarily on the fact that the space density of z2SFGs is much higher than that of lower redshift red galaxies, even when accounting for the merging of z2SFG descendants, which decreases the number density of z2SFG descendants by at most a factor of two by z similar to 0. Of the similar to 50% of z2SFGs that survive to z similar to 0, similar to 70% reside at the center of z similar to 0 dark matter halos with M > 10(12) h(-1) M-circle dot. Halo occupation modeling of z similar to 0 galaxies suggests that such halos are occupied by galaxies with M-r less than or similar to - 20.5, implying that these z2SFGs evolve into typical'' similar to L* galaxies today, including our own Galaxy. The remaining similar to 30% become satellite galaxies by z similar to 0, and comparison to halo occupation modeling suggests that they are rather faint, with M-r less than or similar to - 19.5. These conclusions are qualitatively generic in the sense that any halo-mass-selected sample of galaxies at one epoch will evolve into a more complex and heterogeneous sample of galaxies at a later epoch.