Herschel ATLAS: The angular correlation function of submillimetre galaxies at high and low redshift

TL;DR

This study measures the angular clustering of submillimetre galaxies from the H-ATLAS survey, revealing different clustering behaviors at various wavelengths and redshifts, indicating diverse galaxy populations.

Contribution

First measurement of the angular correlation function of H-ATLAS submillimetre galaxies across multiple wavelengths and redshifts, highlighting the presence of both low and high redshift galaxy populations.

Findings

No significant clustering at 250 microns.

Strong clustering detected at 350 and 500 microns.

High redshift galaxies show r_0 ~ 7-11 h^{-1} Mpc clustering.

Abstract

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.