Spatial Correlation Function of the Chandra Selected Active Galactic Nuclei

We present the spatial correlation function analysis of non-stellar X-ray point sources in the Chandra Large Area Synoptic X-ray Survey of Lockman Hole Northwest (CLASXS). Our 9 ACIS-I fields cover a contiguous solid angle of 0.4 deg and reach a depth of 3 × 10 erg cm s in the 2–8 keV band. We supplement our analysis with data from the Chandra Deep Field North (CDFN). The addition of this field allows better probe of the correlation function at small scales. A total of 233 and 252 sources with spectroscopic information are used in the study of the CLASXS and CDFN fields respectively. We calculate both redshift-space and projected correlation functions in comoving coordinates, averaged over the redshift range of 0.1 < z < 3.0, for both CLASXS and CDFN fields for a standard cosmology with ΩΛ = 0.73,ΩM = 0.27, and h = 0.71 (H0 = 100h km s −1 Mpc). The correlation function for the CLASXS field over scales of 3 Mpc< s < 200 Mpc can be modeled as a powerlaw of the form ξ(s) = (s/s0) , with γ = 1.6 −0.3 and s0 = 8.0 +1.4 −1.5 Mpc. The redshift-space correlation function for CDFN on scales of 1 Mpc< s < 100 Mpc is found to have a similar correlation length s0 = 8.55 +0.75 −0.74 Mpc, but a shallower slope (γ = 1.3± 0.1). The real-space correlation functions derived from the projected correlation functions, are found to be r0 = 8.1 +1.2 −2.2 Mpc, and γ = 2.1± 0.5 for the CLASXS field, and r0 = 5.8 +1.0 −1.5 Mpc, γ = 1.38 +0.12 −0.14 for the CDFN field. By comparing the realand redshift-space correlation functions in the combined CLASXS and CDFN samples, we are able to estimate the redshift distortion Department of Astronomy, University of Maryland, College Park 20742 Laboratory for High Energy Astrophysics, Goddard Space Flight Center, Code 660, NASA, Greenbelt, MD, 20770 Department of Astronomy, University of Wisconsin, Madison, WI 53760 Institute for Astronomy, University of Hawaii, Honolulu, HI 96822