The clustering and halo occupation distribution of Lyman-break galaxies at z ~ 4

Jaehong Park, Han-Seek Kim, J. Stuart B. Wyithe, C. G. Lacey, C. M. Baugh, R. L. Barone-Nugent, M. Trenti, R. J. Bouwens

Published 2015-11-06Version 1

We investigate the clustering of Lyman-break galaxies (LBGs) at z ~ 4. Using the hierarchical galaxy formation model GALFORM, we predict the angular correlation function (ACF) of LBGs and compare this with the measured ACF from survey fields including the Hubble eXtreme Deep Field (XDF) and CANDELS field. We find that the predicted ACFs are in good agreement with the measured ones. However, the predicted ACFs show a weaker dependence on luminosity than is inferred from observations. We show that the fraction of satellite LBGs is important for determining the amplitude of the ACF on small scales. We find that central LBGs at z ~ 4 predominantly reside in haloes of mass ~ 10e11 - 10e12 M_{sun}/h and that satellites reside in larger haloes of mass ~ 10e12 - 10e13 M_{sun}/h. The model predicts fewer bright satellite LBGs at z ~ 4 than are inferred from clustering measurements. We investigate the effect of the photometric scatter in the observations on the ACF predictions. We find that the observational uncertainty in the galaxy luminosity reduces the clustering amplitude, and that this effect increases toward faint galaxies, particularly on small scales. To compare properties of model LBGs with those of observations, this uncertainty must be considered. By analysing the halo occupation distribution (HOD), we find evidence that AGN feedback affects the HOD of central LBGs in massive haloes.