Galaxy clusters at 0.6 < z < 1.4 in the UKIDSS Ultra Deep Survey Early Data Release




We present the first cluster catalogue extracted from the UKIRT Infrared Deep Sky Survey (UKIDSS) Early Data Release. The catalogue is created using UKIDSS Ultra Deep Survey infrared J and K data combined with 3.6- and 4.5-μm Spitzer bands and optical BVRiz′ imaging from the Subaru Telescope over 0.5 deg2 in the Subaru XMM–Newton Deep Field. We have created a new cluster detection algorithm, based on the friends-of-friends and Voronoi tessellation methods, which utilizes probability distribution functions derived from a photometric redshift analysis. We employ mock catalogues to understand the selection effects and contamination associated with the algorithm. The cluster catalogue contains 13 clusters at redshifts 0.61 ≤z≤ 1.39 with luminosities 10 L*≲Ltot≲ 50 L*, corresponding to masses 5 × 1013Mcluster≲ 3 × 1014 M for (M/M)/(L/L) = 75 h. The measured sky surface density of ∼10 clusters deg−2 for high-redshift (z= 0.5–1.5), massive (> 1014 M) clusters is precisely in line with theoretical predictions presented by Kneissl et al.