Luminosity-Dependent Clustering of Star-forming BzK Galaxies at Redshift 2

We use the BzK color selection proposed by Daddi et al.to obtain a sample of 1092 faint star-forming galaxies (sBzK's) from 180 arcmin2 in the Subaru Deep Field. This sample represents star-forming galaxies at 1.4 ≲ z ≲ 2.5 down to KAB = 23.2, which roughly corresponds to a stellar-mass limit of ≃1 × 1010 M☉. We measure the angular correlation function (ACF) of these sBzK's to be w(θ) = (0.58 ± 0.13) × θ(arcsec)-0.8 and translate the amplitude into the correlation length assuming a reasonable redshift distribution. The resulting value, r0 = 3.2 h-1 Mpc, suggests that our sBzK's reside in halos with a typical mass of 2.8 × 1011 M☉. Combining this halo mass estimate with those for brighter samples of Kong et al., we find that the mass of dark halos largely increases with K brightness, a measure of the stellar mass; the dark halo mass increases by as much as 102-103 as K brightness increases by only a factor of ≃10. We also find that the halo occupation number, the number of galaxies hosted in a dark halo, is higher for brighter sBzK's. Comparison with other galaxy populations suggests that faint sBzK's (KAB < 23.2) and Lyman break galaxies at z ~ 2 are similar populations hosted by relatively low-mass halos, while bright sBzK's (KAB < 21) reside in halos comparable to or more massive than those of distant red galaxies and extremely red objects. Using the extended Press-Schechter formalism, we predict that present-day descendants of halos hosting sBzK's span a wide mass range depending on K brightness, from lower than that of the Milky Way up to those of richest clusters.