Mapping Large-Scale Structure with Radio Sources

Abstract

In regions away from the Galactic plane, formal tests indicate an isotropic, random and independent distribution of radio sources on the sky (e.g.[1], although there are strong indications of large-scale anomalies (e.g.[2], [3]). An accommodation of these results was suggested by Shaver and Pierre [4] and by Shaver [5] who showed that the large-scale deviations could be due to the supergalaxy, a possibility which had been noted by Pauliny-Tothet al.in 1978 [6]. As to the influence ofothersuperclusters, or indeed the cellular structure of the universe in which galaxies cluster on scales up to at least 100h−1Mpc (e.g.[7]), at what flux-density level does this large-scale structure become apparent? Conversely, what can be learnt about structure on the largest scales through the sky distribution of radio sources? Here we describe three investigations in various stages of completion which consider these issues.