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

TL;DR

This study uses large-scale N-body simulations to predict the clustering of high-redshift galaxy-hosting halos, indicating that JWST surveys could detect their clustering with relatively small samples due to strong bias.

Contribution

It provides the first detailed prediction of high-redshift halo clustering at z=8-10 using a 130-billion-particle simulation with new initial condition corrections and Planck cosmology.

Findings

High bias factors (5-30) for halos hosting JWST-detectable galaxies.

Correlation lengths comparable to present-day galaxies (5-10 Mpc/h).

Potential for clustering detection with small survey sizes (25 Mpc/h) and 500-1000 objects.

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 $10^9$ to $10^{11}$ $h^{-1}\;M_\odot$, 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--10$h^{-1}\;{\rm Mpc}$, similar to that of today's galaxies. Our results are based on a simulation of 130 billion particles in a box of $250h^{-1}\;{\rm Mpc}$ 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 25$h^{-1}\;{\rm Mpc}$ 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.