Satellites around Edge-on Galaxies. I. Dynamical Masses

We have undertaken a search for satellites around edge-on galaxies in the EGIPS catalog, which contains 16 551 objects with declinations above . We searched for systems with a central galaxy dominating in brightness by at least compared to its companions. As a result, we discovered 1097 candidate satellites around 764 EGIPS galaxies with projected distances less than 500 kpc and a radial velocity difference less than 300 km s . Of these, 757 satellites around 547 central galaxies have radial velocity accuracies higher than 20 km s and satisfy the gravitationally bound condition. The ensemble of satellites is characterized by an average projected distance of 84 kpc and an average radial velocity dispersion of 103 km s . Treating small satellites as test particles moving on isotropic orbits around central EGIPS galaxies, we determined the projected (orbital) masses of the edge-on galaxies. Within the luminosity range of to , the total mass of the systems is well described by a linear dependence with an average total mass-to- -band luminosity equal to , which is typical for nearby spiral galaxies such as the Milky Way, M 31 and M 81.