Strong spatial clustering of ultraviolet-selected galaxies with magnitude Ks < 20.5 and redshift z ∼ 2

We obtained deep 8.'5 x 8.'5 near-infrared (IR) images within four high-redshift survey fields, measured the K-s magnitudes of 300 optically selected galaxies with spectroscopic redshift 1.8 less than or similar to x less than or similar to 2.6, and compared the spatial clustering strength of galaxies with K-s < 20.5 and K-s > 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 sigma), 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 agrees well with that K-s < 20.5 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.