Uncovering High-z Clusters Using Wide-Angle Tailed Radio Sources

The morphologies of wide-angle tailed (WAT) radio sources (edge-darkened, C-shaped, FR I radio sources) are the result of confinement and distortion of the radio lobes by the dense X-ray-emitting gas in clusters or groups of galaxies. These radio sources are easily seen at high redshifts (z ∼ 1) in short-exposure images from the Faint Images of the Radio Sky at Twenty-cm (FIRST) survey. Using a sample of approximately 400 WAT sources from the FIRST survey, we have discovered a number of high-z clusters. Here, we present the highestz cluster found so far using this method: 1137+3000 at z = 0.96. We include photometric and spectroscopic results. Ten galaxies are confirmed at the cluster redshift, with a line-of-sight velocity dispersion of σ = 530+190 −90 km s −1, typical of an Abell richness class 0 cluster.