The Southern Supercluster

The Southern Supercluster is the closest supercluster to the Local Supercluster. The densest region of this supercluster lies between supergalactic longitudes 200^deg^ and 310^deg^ and supergalactic latitudes - 38^deg^ to -45^deg^, which correspond to right ascensions of 2 to 6 hr and declinations of + 5^deg^ to -69^deg^. From the contour maps made of galaxies from the Second Reference Catalogue of Bright Galaxies (RC2), two regions, A (180^deg^ <= L <= 320^deg^, -30^deg^ >= B >= -50^deg^) and B (260^deg^ <= L <= 360^deg^, 0^deg^ >= B >= -30^deg^) were delineated for detailed study. Galaxies from five catalogs were compiled and the basic parameters, diameters and axis ratios, were reduced to the RC2 system. Magnitudes measured for 105 galaxies, most of them new, are presented. The magnitudes for other galaxies were obtained from the RC3 (in preparation). The radial velocities were culled from the literature. A self-consistent distance scale was established using tertiary distance indicators-the luminosity index {LAMBDA}_c_, and the maximum rotation velocity log V_m_ obtained from H I linewidths. The distance moduli were obtained using parameters log D_0_ and B^0^_T_. The distance moduli derived from the central velocity dispersion of early-type galaxies, diameters of inner rings, and the method of "sosie" galaxies were obtained from other catalogs. A database was assembled containing several parameters like log D, B^0^_T_, mu, V, etc. A statistical study of their distribution was made and a measure of their completeness estimated. It was shown for galaxies brighter than 14.0 mag that the probability that this areal distribution could have arisen by chance was less than 10^-3^. Several maps were constructed to investigate the structure of the supercluster in three dimensions using the positional coordinates and a distance estimate from the radial velocity. The extent, size, and shape of the super-cluster were determined. The supercluster lies within the velocity range 560-2240 km/s and has a velocity dispersion of 345 km/s. It is 41 Mpc along its longest dimension and is at a mean distance of 20 Mpc. Fifteen groups belonging to the supercluster were identified. The mass, luminosity, and mass-to-light ratio of the groups were computed. The mean mass-to-light ratio was 100h (h=H/100). The total luminosity of the supercluster was estimated to be 2.4 x 10^12^h^-2^ L_sun_ after making corrections for incompleteness. The total mass of the supercluster was estimated to be 2.4 x 10^12^h^-2^ L_sun_. The Southern Supercluster is comparable to the Coma and Hercules superclusters in terms of mass and luminosity. Even though the Southern Supercluster is the nearest supercluster to the Local Supercluster, the two are not physically linked. However, there seems to be a tenuous connection between the Southern Supercluster and the Perseus Supercluster.