Abstract
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.
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