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 that contribute to the integrated line of sight mass density .
We conclude that galaxies have no definite edges of the matter distribution , extending to the middle to neighbouring 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 } \sim 0.27 and typically \Omega _ { gal } \sim 0.15 from the luminosity density multiplied by the mass to light ratio .
We suggest to use a physical method of gravitational lensing to characterise galaxy samples rather than characterise them with photometric means .