SIMBAD references

The mass M and the radius R_h of the Centaurus A group are estimated from the positions and radial velocities of 30 probable cluster members. For an assumed distance of 3.9 Mpc, it is found that R_h∼640 kpc. The velocity dispersion in the Cen A group is 114±21 km.s^–1. From this value and R_h=640 kpc, the virial theorem yields a total mass of 1.4x10¹³ M_☉ for the Cen A group. The projected mass method gives a mass of 1.8x10¹³ M_☉. These values suggest that the Cen A group is about 7 times as massive as the Local Group. The Cen A mass-to-light ratio is found to be M/L_B=155-200 (M/L)_☉. The cluster has a zero-velocity radius R₀=2.3 Mpc.