FAINT SUBMILLIMETER GALAXIES IDENTIFIED THROUGH THEIR OPTICAL/NEAR-INFRARED COLORS. I. SPATIAL CLUSTERING AND HALO MASSES

The properties of submillimeter galaxies (SMGs) that are fainter than the confusion limit of blank-field single-dish surveys (S-850 less than or similar to 2 mJy) are poorly constrained. Using a newly developed color selection technique, Optical-Infrared Triple Color (OIRTC), that has been shown to successfully select such faint SMGs, we identify a sample of 2938 OIRTC-selected galaxies, dubbed Triple Color Galaxies (TCGs), in the UKIDSS-UDS field. We show that these galaxies have a median 850 mu m flux of S-850 = 0.96 +/- 0.04 mJy (equivalent to a star formation rate SFR similar to 60-100 M-circle dot yr(-1) based on spectral energy distribution fitting), representing the first large sample of faint SMGs that bridges the gap between bright SMGs and normal star-forming galaxies in S-850 and L-IR. We assess the basic properties of TCGs and their relationship with other galaxy populations at z similar to 2. We measure the two-point autocorrelation function for this population and derive a typical halo mass of log(10)(M-halo) = 12.9(-0.3)(+0.2), 12.7(-0.2)(+0.1), and 12.9(-0.3)(+0.2) h(-1) M-circle dot at z = 1-2, 2-3, and 3-5, respectively. Together with the bright SMGs (S-850 greater than or similar to 2 mJy) and a comparison sample of less far-infrared luminous star-forming galaxies, we find a lack of dependence between spatial clustering and S-850 (or SFR), suggesting that the difference between these populations may lie in their local galactic environment. Lastly, on the scale of similar to 8-17 kpc at 1 < z < 5 we find a tentative enhancement of the clustering of TCGs over the comparison star-forming galaxies, suggesting that some faint SMGs are physically associated pairs, perhaps reflecting a merging origin in their triggering.