The angular clustering of distant galaxy clusters

We discuss the angular clustering of galaxy clusters at z > 1 selected within 50 deg(2) from the Spitzer Wide-Infrared Extragalactic survey. We use a simple color selection to identify high-redshift galaxies with no dependence on galaxy rest-frame optical color using Spitzer IRAC 3.6 and 4.5 mu m photometry. The majority (> 90%) of galaxies with z > 1.3 are identified with ([3.6] - [4.5])(AB) > -0.1 mag. We identify candidate galaxy clusters at z > 1 by selecting overdensities of >= 26 - 28 objects with [3.6] - [4.5])(AB) > -0.1 mag within radii of 1.4', which corresponds to r < 0.5 h(-1) Mpc at z = 1.5. These candidate galaxy clusters show strong angular clustering, with an angular correlation function represented by w(theta) = (3.1 +/- 0.5)(theta/1')(-1.1 +/- 0.1) over scales of 2' - 100'. Assuming the redshift distribution of these galaxy clusters follows a fiducial model, these galaxy clusters have a spatial-clustering scale length r(0) = 22.4 +/- 3.6 h(-1) Mpc and a comoving number density n = 1.2 +/- 0.1 x 10(-5) h(3) Mpc(-3). The correlation scale length and number density of these objects are comparable to those of rich galaxy clusters at low redshift. The number density of these high-redshift clusters corresponds to dark matter halos larger than (3-5) x 10(13) h(-1) M center dot at z = 1.5. Assuming the dark halos hosting these high-redshift clusters grow following Lambda CDM models, these clusters will reside in halos larger than ( 1 2); 10(14) h(-1) M center dot at z = 0.2, comparable to rich galaxy clusters.