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Session 13 - Observations of Radio Sources.
Display session, Monday, January 15
North Banquet Hall, Convention Center
One effect of a dense intracluster medium is to make the lobes of an embedded radio galaxy appear ``bent'' or pushed back as the galaxy moves through the medium. As Burns et al. (1993) recently suggested, ``radio galaxies may be good pointers to clusters,'' and those with the bent double morphology may fulfill this role especially well. The FIRST survey has detected approximately 138,000 radio sources to date of which more than 12,000 are double or multiple sources. We have selected nearly 450 objects which exhibit the bent double morphology and present the preliminary results of the optical follow up observations for a subset of these sources. Many of the imaged fields exhibit clear evidence of a faint galaxy cluster at the position of the bent double source. For the brightest such cluster observed to date, we have obtained redshifts for the two brightest cluster galaxies (both of which are radio sources) and find z=0.26. We present the flux and angular size distributions of the bent double sample, the statistics of the optical images we have obtained, and the prospects for obtaining a large sample of high-redshift clusters using this search technique.
This work is supported by grants from the National Science Foundation, NATO, the National Geographic Society, IGPP at Lawrence Livermore National Laboratory, and Columbia University.
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