A High-Resolution Survey of the Coma Cluster of Galaxies at 408 Mc./s.

Abstract

IN December 1958 an area of sky including the Coma cluster of galaxies was surveyed using the 250-ft. radio telescope at Jodrell Bank¹ with a Dicke-type radiometer, pass-band 408 ± 2 Mc./s., and noise figure 6 db. The beam was elliptical, having half-power widths of 40 and 56 minutes of arc. The system was calibrated using the radio source 14N5A, which was assumed to have a flux of 47 × 10⁻²⁶ W. m.⁻² (c./s.)⁻¹ (ref. 2). The intensity contours for the region are shown in Fig. 1; Fig. 2 is a sample scan through the cluster and Table 1 gives the fluxes and positions of sources which can be resolved from the extremely complex background.