Clustering of extremely red objects in the Subaru GTO 2deg² field

We study the angular correlation function of bright (K_s ≤ 19.5) Extremely Red Objects (EROs) selected in the Subaru GTO 2 deg² field. By applying the color selection criteria of R − K_s > 5.0, 5.5, and 6.0, we identify 9055, 4270, and 1777 EROs, respectively. The number density is consistent with similar studies on the optical − NIR color selected red galaxies. The angular correlation functions are derived for EROs with different limiting magnitude and different R − K_s color cut. When we assume that the angular correlation function ω(θ) follows a form of a power-law (i.e., ω(θ) = A θ^−δ), the value of the amplitude A was larger for brighter EROs compared to the fainter EROs. The result suggests that the brighter, thus more massive high-redshift galaxies, are clustered more strongly compared to the less massive galaxies. Assuming that EROs have redshift distribution centered at hzi ∼ 1.1 with σ_z = 0.15, the spatial correlation length r₀ of the EROs estimated from the observed angular correlation function ranges ∼ 6-10 h⁻¹ Mpc. A comparison with the clustering of dark matter halos in numerical simulation suggests that the EROs are located in most massive dark matter halos and could be progenitors of L∗ elliptical galaxies.