Abstract
A family of potential-density pairs has been found for spherical halos and bulges of galaxies within the Newtonian limit of scalar-tensor theories of gravity. The scalar field is described by a modified Helmholtz equation with a source that is coupled to the standard Poisson equation of Newtonian gravity. Then, the net gravitational force is given by two contributions: the standard Newtonian potential plus a term stemming from massive scalar fields. General solutions have been found for spherical systems. Hence, we compute potential-density pairs of spherical, galactic systems, and their associated circular velocities
