Local Field of Galaxy Velocities

A sample of 145 galaxies having radial velocities relative to the centroid of the Local Group V _LG < 500 km/sec and estimated photometric distances D < 8 Mpc is considered. The field of peculiar velocities of these galaxies is estimated using the tensor of the local value of the Hubble constant H _ij , with principal values of 81:62:48 in km/sec·Mpc, which have a standard error of 4 km/sec·Mpc. The minor axis of the Hubble ellipsoid is oriented almost along the polar axis of the Local Supercluster, while the major axis forms an angle = (29 ± 5)° with the direction toward the center of the Virgo Cluster. Such a configuration of the peculiar-velocity field shows unsatisfactory agreement with the model of a spherically symmetric flow of galaxies toward the Virgo Cluster. Rotation of the Local Supercluster may be one reason for this difference. The peculiar velocities of galaxies within a volume with D < 8 Mpc are characterized by a dispersion _V = 74 km/sec, a considerable part of which is due to the virial motions of galaxies in groups and to distance errors. For field galaxies, located in a layer of 1 < D < 3 Mpc around the Local Group, the radial-velocity dispersion does not exceed 25 km/sec. The velocity—distance relation, constructed from the 20 closest galaxies around the Local Group with D < 3 Mpc and with errors (D) < 0.2 Mpc, exhibits the expected effect of gravitational deceleration. Using the estimate of R ₀ = (0.96 ± 0.05) Mpc for the observed radius of the zero-velocity sphere, we determined the total mass of the Local Group to be (1.2 ± 0.2)·10¹² M , which agrees well with the sum of the virial masses of the subgroups of galaxies around the Local Group and M31. The ratio of the Local Group's total mass (within R ₀) to its luminosity is M/L = (23 ± 4) M /L , which does not require the existence of supermassive dark halos around our Galaxy and M31.