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Keywords:

  • cosmology: large-scale structure of the Universe;
  • submillimetre: galaxies

ABSTRACT

We discuss and compare two alternative models for the two-point angular correlation function of galaxies detected through the submillimetre emission using the Herschel Space Observatory. The first, now-standard Halo Model, which represents the angular correlations as arising from one-halo and two-halo contributions, is flexible but complex and rather unwieldy. The second model is based on a much simpler approach: we incorporate a fitting function method to estimate the matter correlation function with approximate model of the bias inferred from the estimated redshift distribution to find the galaxy angular correlation function. We find that both models give a good account of the shape of the correlation functions obtained from published preliminary studies of the Herschel Multi-tiered Extragalactic Survey (HerMES) and the Herschel-Astrophysical Terahertz Large Area Survey (H-ATLAS) performed using Herschel, and yield consistent estimates of the minimum halo mass within which the submillimetre galaxies must reside. We note also that both models predict an inflection in the correlation function at intermediate angular scales, so the presence of the feature in the measured correlation function does not unambiguously indicate the presence of intra-halo correlations. The primary barrier to more detailed interpretation of these clustering measurements lies in the substantial uncertainty surrounding the redshift distribution of the sources.