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

Abstract

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 of 10 9 –10 11 h −1 M ⊙ , which are those expected to host galaxies detectable with JWST , are highly clustered with bias factors ranging from 5 to 30 depending strongly on mass, as well as on redshift and scale. This results in correlation lengths of 5–10 h −1 Mpc, similar to those of today’s galaxies. Our results are based on a simulation of 130 billion particles in a box of size 250 h −1 Mpc using our new high-accuracy Abacus  simulation code, the corrections to cosmological initial conditions of Garrison et al., and the Planck 2015 cosmology. We use variations between sub-volumes to estimate the detectability of the clustering. Because of the very strong interhalo clustering, we find that a medium-sized survey with a transverse size of the order of 25 h −1 comoving Mpc (about 13′) 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.