Which haloes host Herschel-ATLAS galaxies in the local Universe?
Rodighiero, G.; Ivison, R. J.; Baugh, Carlton M.; de Zotti, G.; van Kampen, E.; Fritz, J.; Cooray, A.; Ibar, E.; Bamford, S. P.; Auld, R.; Cava, A.; Dariush, A.; Dunne, L.; Dye, S.; Eales, S.; Hopwood, R.; Pohlen, M.; Guo, Qi; Maddox, S. J.; Bourne, N.; Pascale, E.; Prescott, M.; Baldry, I. K.; Jones, D. H.; Loveday, J.; Rigby, E. E.; Sharp, R.; Smith, D. J. B.; Temi, P.; Cole, Shaun; Norberg, Peder; Jarvis, M.; Peacock, J. A.; Lacey, Cedric G.; Hopkins, A.; Frenk, Carlos S.; Driver, S.; Kelvin, L.; Liske, J.; Robotham, A.; Croom, S.; Parkinson, H.; Buttiglione, E. S.
United Kingdom, Italy, Spain, United States, Australia, Belgium, Germany
Abstract
We measure the projected cross-correlation between low-redshift (z < 0.5) far-infrared selected galaxies in the science demonstration phase (SDP) field of the Herschel-ATLAS (H-ATLAS) survey and optically selected galaxies from the Galaxy and Mass Assembly (GAMA) redshift survey. In order to obtain robust correlation functions, we restrict the analysis to a subset of 969 out of 6900 H-ATLAS galaxies, which have reliable optical counterparts with r < 19.4 mag and well-determined spectroscopic redshifts. The overlap region between the two surveys is 12.6 deg2; the matched sample has a median redshift of z≈ 0.2. The cross-correlation of GAMA and H-ATLAS galaxies within this region can be fitted by a power law, with correlation length r0≈ 4.63 ± 0.51 Mpc. Comparing with the corresponding autocorrelation function of GAMA galaxies within the SDP field yields a relative bias (averaged over 2-8 Mpc) of H-ATLAS and GAMA galaxies of bH/bG≈ 0.6. Combined with clustering measurements from previous optical studies, this indicates that most of the low-redshift H-ATLAS sources are hosted by haloes with masses comparable to that of the Milky Way. The correlation function appears to depend on the 250-μm luminosity, L250, with bright (median luminosity νL250∼ 1.6 × 1010 L⊙) objects being somewhat more strongly clustered than faint (νL250∼ 4.0 × 109 L⊙) objects. This implies that galaxies with higher dust-obscured star formation rates are hosted by more massive haloes.