Princeton University Survey Science Discussion

I present the evolution of the relationship between galaxy stellar mass and their host dark matter halo mass since the Universe was only about a billion years old (z ~ 5) until today. The galaxy-halo mass relationship was constrained through the measurements of two-point clustering of galaxies and stellar mass functions in the UDS and COSMOS fields in concert with Halo Occupation Distribution (HOD) modeling. The use of two large fields covering an effective area of ~1.6 square degrees was vital in lowering the measurement uncertainties due to cosmic variance. On the other hand, I test various novel redshift evolution schemes for the HOD model which allows tracing a continuous evolution of stellar-halo mass relationship (SHMR) out to z~5. But even more importantly, it allows for the constraining of the SHMR at high redshift where the data is not as strongly constraining as it is at low redshift. This study confirms the consensus in the literature that the efficiency of dark matter halos in converting baryons into stellar mass peaks at ~20%, at a halo mass of ~10^12 M⊙, out to z~5. Furthermore, from the resulting SHMR evolution, I also show how the role of Active Galactic Nuclei (AGN) feedback, in suppressing star formation, evolves with time. This is highly illuminating for the simulations.