Herschel ATLAS: The angular correlation function of submillimetre
  galaxies at high and low redshift
  We present measurements of the angular correlation function of galaxies
selected from the first field of the H-ATLAS survey. Careful removal of the
background from galactic cirrus is essential, and currently dominates the
uncertainty in our measurements. For our 250 micron-selected sample we detect
no significant clustering, consistent with the expectation that the 250
micron-selected sources are mostly normal galaxies at z<~ 1. For our 350 micron
and 500 micron-selected samples we detect relatively strong clustering with
correlation amplitudes A of 0.2 and 1.2 at 1', but with relatively large
uncertainties. For samples which preferentially select high redshift galaxies
at z~2-3 we detect significant strong clustering, leading to an estimate of r_0
~ 7-11 h^{-1} Mpc. The slope of our clustering measurements is very steep,
delta~2. The measurements are consistent with the idea that sub-mm sources
consist of a low redshift population of normal galaxies and a high redshift
population of highly clustered star-bursting galaxies.
