Testing the Detection Significance on the Large Scale Structure by a JWST Deep Field Survey

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In preparation for deep extragalactic imaging with the James Webb Space Telescope, we explore the clustering of massive halos at z=8 and 10 using a large N-body simulation. We find that halos with masses 10⁹ to 10¹¹ h⁻¹M, which are those expected to host galaxies detectable with JWST, are highly clustered with bias factors ranging from 5 and 30 depending strongly on mass, as well as on redshift and scale. This results in correlation lengths of 5--10h⁻¹ Mpc, similar to that of today's galaxies. Our results are based on a simulation of 130 billion particles in a box of 250h⁻¹ Mpc size using our new high-accuracy ABACUS simulation code, the corrections to cosmological initial conditions of (Garrison et al. 2016, 2016MNRAS.461.4125G), and the Planck 2015 cosmology. We use variations between sub-volumes to estimate the detectability of the clustering. Because of the very strong inter-halo clustering, we find that surveys of order 25h⁻¹ Mpc comoving transverse size may be able to detect the clustering of z=8--10 galaxies with only 500-1000 survey objects if the galaxies indeed occupy the most massive dark matter halos.