THE CLUSTERING PROPERTIES OF THE FIRST GALAXIES

We study the clustering properties of the first galaxies formed in the universe. We find that, due to chemical enrichment of the interstellar medium by isolated Population III stars formed in mini-halos at redshift z greater than or similar to 30, the (chronologically) first galaxies are composed of metal-poor Population II stars and are highly clustered on small scales. In contrast, chemically pristine galaxies in halos with mass M similar to 10(8) M-circle dot may form at z < 20 in relatively underdense regions of the universe. This occurs once self-enrichment by Population III in mini-halos is quenched by the buildup of an H-2 photodissociating radiative background in the Lyman-Werner bands. We find that these chemically pristine galaxies are spatially uncorrelated. Thus, we expect that deep fields with the James Webb Space Telescope (JWST) may detect clusters of chemically enriched galaxies but individual chemically pristine objects. We predict that metal-free galaxies at 10 less than or similar to z less than or similar to 15 have surface densities of about 80 arcmin(-2) and per unit redshift but most of them will be too faint even for JWST. However, the predicted density makes these objects interesting targets for searches behind lensing clusters.