Preliminary VLA limits on the Sunyaev-Zel'dovich effect in Abell 2218

Abstract

In an attempt to apply radio interferometry or Fourier synthesis methods to the search for the Sunyaev-Zel'dovich effect, the authors used the Very Large Array in its D configuration to map Abell cluster 2218 at λ = 6 cm. The phase center of the maps was offset from the cluster center to minimize systematic effects seen in other deep surveys. The presence of radio sources in the cluster and other, apparently instrumental, effects discussed here limited the sensitivity to the Sunyaev-Zel'dovich effect to ΔT ≈ 0.7 mK at an angular resolution of 60arcsec-80arcsec.