2013ApJ...764...31P

We measure the clustering of extremely red objects (EROs) in ~8 deg² of the NOAO Deep Wide Field Survey Boötes field in order to establish robust links between ERO (z ~ 1.2) and local galaxy (z < 0.1) populations. Three different color selection criteria from the literature are analyzed to assess the consequences of using different criteria for selecting EROs. Specifically, our samples are (R - K_s) > 5.0 (28, 724 galaxies), (I - K_s) > 4.0 (22, 451 galaxies), and (I - [3.6]) > 5.0 (64, 370 galaxies). Magnitude-limited samples show the correlation length (r₀) to increase for more luminous EROs, implying a correlation with stellar mass. We can separate star-forming and passive ERO populations using the (K_s- [24]) and ([3.6] - [24]) colors to K_s= 18.4 and [3.6] = 17.5, respectively. Star-forming and passive EROs in magnitude-limited samples have different clustering properties and host dark halo masses and cannot be simply understood as a single population. Based on the clustering, we find that bright passive EROs are the likely progenitors of ≳ 4L* elliptical galaxies. Bright EROs with ongoing star formation were found to occupy denser environments than star-forming galaxies in the local universe, making these the likely progenitors of ≳ L* local ellipticals. This suggests that the progenitors of massive ≳ 4L* local ellipticals had stopped forming stars by z ≳ 1.2, but that the progenitors of less massive ellipticals (down to L*) can still show significant star formation at this epoch.