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 inter-stellar medium
by isolated Population III stars formed in mini-halos at redshift z>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~10^8 M_sun 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 build-up of an $H_2$
photo-dissociating 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 may detect clusters of
chemically enriched galaxies but individual chemically pristine objects. We
predict that metal-free galaxies at 10 <= z <= 15$ have surface densities of
about 80 per square arcmin 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.
