Triplets of Galaxies in the Local Supercluster . I . Kinematic and Virial Parameters

We considered kinematic and virial parameters of a sample of galaxy triplets from the Local Supercluster (LS). The galaxies were selected from the LEDA database, and their radial velocities are no more than 3100 km/s. The sample contains 176 systems selected according to the Karachentsev criterion. We calculated the following median parameters of the LS triplets: rms velocity of galaxies with respect to triplet center, Sv = 30 km/s; harmonic mean radius, Rh = 160 kpc; virial mass, Mvir = 3.6 · 10 11M⊙; and mass-to-light ratio, Mvir/L = 35M⊙/L⊙. Although various investigators used different approaches to compile samples of triple systems, general properties of the triplets in all the samples we considered agree rather satisfactorily. The LS triplets have the least mass-to-light ratio as compared to other galaxy triplet samples.