ISOLATED DWARF GALAXIES IN THE LOCAL SUPERCLUSTER AND ITS SURROUNDINGS

We present a list of 75 isolated dwarf galaxies of later types which have no neighbors with a relative radial velocity difference of less than 500 km/s or projected distances of less than 500 kpc. These were selected from similar to 2000 dwarf galaxies with radial velocities V-LG<3500 km/s within the volume of the local supercluster. In terms of their sizes, luminosities, and the amplitudes of their internal motions, the isolated dwarf galaxies do not differ significantly from gas-rich dwarf galaxies in groups and clusters. However, the median mass of neutral hydrogen per unit luminosity for the isolated galaxies is a factor of two greater than for the galaxies of later types in groups. We have also identified 10 presumably isolated spheroidal dwarf galaxies. The discovery of isolated dwarf galaxies populated exclusively by old stars is of great interest for modern cosmological scenarios of galaxy formation.