MATTER DISTRIBUTION AROUND GALAXIES

We explore the mass distribution of material associated with galaxies from the observation of gravitational weak lensing for the galaxy mass correlation function with the aid of N-body simulations of dark matter. The latter is employed to unfold various contributions to the integrated line-of-sight mass density. We conclude that galaxies have no definite edges of the matter distribution, extending to the middle of neighboring galaxies with the density profile roughly r(-2.4) beyond the virial radius. The mass distributed beyond the virial radius (gravitationally bound radius) explains the gap seen in the mass density estimates, the global value Omega(m) similar to 0.27 and typically Omega(gal) similar to 0.15 from the luminosity density multiplied by the mass-to-light ratio. We suggest using a physical method of gravitational lensing to characterize galaxy samples rather than characterizing them by photometric means.