MULTICOLOR PHOTOMETRY OF THE SHAPLEY 8 CLUSTER OF GALAXIES

In a previous paper, we measured 40 redshifts in the core of the rich southern cluster Shapley 8. We now present photographic b26.75 magnitudes, radii and ellipticities, together with (u - b) and (b - r) colours for 4903 galaxies within a 4.69 square degree field around this cluster. We have also measured (r - i) colours for a subset of these galaxies around the cluster core. Our sample is essentially complete to b26.75 = 20.85. We discuss the colour-related properties of the cluster, together with its luminosity function and spatial distribution. We find a deficit of blue galaxies in the cluster core, implying morphological segregation, and also evidence that the brightest galaxies are less tightly clustered than the rest. There is a clear change of slope at M(b) almost-equal-to 0.4 in the ultraviolet colour-magnitude relations for the E/SO galaxies. We also show how the colour data can be used to isolate high-redshift background galaxies. The mass enclosed within the area we have studied is 4.5 x 10(15) M., which appears to be too low for the Shapley Supercluster to be the explanation of the 'Great Attractor'.