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

Abstract

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 highest-z 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 530 +190/-90 km/s, typical of an Abell richness class 0 cluster.

5 pages, 3 figures; to appear in Carnegie Observatories Astrophysics Series, Vol. 3: Clusters of Galaxies: Probes of Cosmological Structure and Galaxy Evolution, ed. J. S. Mulchaey, A. Dressler, and A. Oemler (Pasadena: Carnegie Observatories, http://www.ociw.edu/ociw/symposia/series/symposium3/proceedings.html)