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E. L. Blanton (Carnegie Mellon University / Columbia University)
An imaging and spectroscopic study of 384 bent-double radio sources selected from the VLA FIRST survey is presented. In most models, the bending of the sources' lobes is a result of interaction with a dense intra-cluster medium in which the host galaxies are embedded. Therefore, these types of radio objects should act as tracers of clusters of galaxies.
We find that approximately 60% of the bent doubles are located in cluster environments with Abell richness class 0 or greater. The remaining 40% are found in groups (some of them poor). We discuss possible scenarios that could produce bent doubles in these surroundings. Several radio and optical properties of the bent doubles and their environments are examined for possible correlations. The results are consistent with similar studies done for radio sources found in Abell clusters.
Several moderate-to-high-z bent double sources are studied in detail, and spectroscopy confirms them to be associated with rich clusters. These clusters represent the most distant clusters known (up to z = 0.95) that are associated with wide-angle-tail (WAT) radio sources. The WAT morphology is the most common one in our sample; these sources are high-power FR Is with large linear extents and opening angles and are usually found to be associated with cD galaxies in the cores of clusters.
The FIRST project is supported by grants from the National Geographic Society, the National Science Foundation (AST-94-19906), NASA (NAG5-6035), NATO, IGPP, Columbia University, and Sun Microsystems.
The author(s) of this abstract have provided an email address for comments about the abstract: eblanton@andrew.cmu.edu