ROSAC: Studying the clustering properties of X-ray selected AGNs
  We present the first ROSAC results of an AGN clustering analysis. This study comprises a sample of 200 AGNs, 75% of which being at low redshifts z<0.5, in the Ursa Major constellation. The spatial 2-point-correlation function (SCF) as well as the minimal spanning tree (MST) technique were applied. Some evidence for clustering is found in the SCF, although with low significance. Using the MST technique, we could find two AGN groups. This result is preliminary and the exact significance will be tested with careful simulations. 
F. Tesch (1), F. J. Carrera (2 and 3), D. Engels (1), J. Hu (4), C.   Ledoux(5), A. Ugryumov(6), D. Valls-Gabaud(7), W. Voge...