Definitive Identification of the Transition between Small- and Large-Scale Clustering for Lyman Break Galaxies

Abstract

We report angular correlation function (ACF) of Lyman Break Galaxies (LBGs)\nwith unprecedented statistical quality on the basis of 16,920 LBGs at z=4\ndetected in the 1 deg^2 sky of the Subaru/XMM-Newton Deep Field. The ACF\nsignificantly departs from a power law, and shows an excess on small scale.\nParticularly, the ACF of LBGs with i'<27.5 have a clear break between the small\nand large-scale regimes at the angular separation of ~7'' whose projected\nlength corresponds to the virial radius of dark halos with a mass of 10^11-12\nMo, indicating multiple LBGs residing in a single dark halo. Both on small\n(2''<theta<3'') and large (40''<theta<400'') scales, clustering amplitudes\nmonotonically increase with luminosity for the magnitude range of i'=24.5-27.5,\nand the small-scale clustering shows a stronger luminosity dependence than the\nlarge-scale clustering. The small-scale bias reaches b~10-50, and the outskirts\nof small-scale excess extend to a larger angular separation for brighter LBGs.\nThe ACF and number density of LBGs can be explained by the cold dark matter\nmodel.\n