CONSTRAINING HALO OCCUPATION PROPERTIES OF X-RAY ACTIVE GALACTIC NUCLEI USING CLUSTERING OF CHANDRA SOURCES IN THE BOOTES SURVEY REGION

We present one of the most precise measurements to date of the spatial clustering of X-ray-selected active galactic nuclei (AGNs) using a sample derived from the Chandra X-ray Observatory survey in the Bootes field. The real-space two-point correlation function over a redshift interval from z = 0.17 to z similar to 3 is well described by the power law,. xi(r) = (r/r(0))-(gamma), for comoving separations r less than or similar to 20 h(-1) Mpc. We find gamma = 1.84 +/- 0.12 and gamma(0) consistent with no redshift trend within the sample (varying between r(0) = 5.5 +/- 0.6 h(-1) Mpc for < z > = 0.37 and r(0) = 6.9 +/- 1.0 h(-1) Mpc for < z > = 1.28). Furthermore, we are able to measure the projections of the two-point correlation function both on the sky plane and in the line of sight. We use these measurements to show that the Chandra/Bootes AGNs are predominantly located at the centers of dark matter halos with circular velocity v(max) > 320 km s(-1) or M-180 > 4.1 x 10(12) h(-1) M-circle dot, and tend to avoid satellite galaxies in halos of this or higher mass. The halo occupation properties inferred from the clustering properties of Chandra/Bootes AGNs-the mass scale of the parent dark matter halos, the lack of significant redshift evolution of the clustering length, and the low satellite fraction-are broadly consistent with the Hopkins et al. scenario of quasar activity triggered by mergers of similarly sized galaxies.