Strong Spatial Clustering of Ultraviolet-selected Galaxies with Magnitude Ks < 20.5 and Redshift z ~ 2

We obtained deep 8.′5 × 8.′5 near-infrared (IR) images within four high-redshift survey fields, measured the Ks magnitudes of 300 optically selected galaxies with spectroscopic redshift 1.8 ≲ z ≲ 2.6, and compared the spatial clustering strength of galaxies with Ks < 20.5 and Ks > 20.5. We found at greater than 95% confidence that the brighter galaxies cluster more strongly. The best-fit correlation lengths for the bright and faint samples are 10 ± 3 and 4 ± 0.8 h-1 comoving Mpc, respectively (1 σ), although the unusual density of bright QSOs in one of our survey fields may imply that the result is not representative of the universe as a whole. Neglecting this possibility, the correlation length for the optically selected sample with Ks < 20.5 agrees well with that reported for comparably bright near-IR-selected samples. The differences in correlation length between optically selected and near-IR-selected samples have been presented as evidence that the two techniques find orthogonal populations of high-redshift galaxies. Our results favor a more nuanced view.