Linear potentials and galactic rotation curves - detailed fitting
  We continue our study of the astrophysical implications of the linear potential $V(r)=-\beta c^2/r+\gamma c^2 r/2$ associated with fundamental gravitational sources in the conformal invariant fourth order theory of gravity which has recently been advanced by Mannheim and Kazanas as a candidate alternative to the standard second order Einstein theory. We provide fitting to the rotation curves of an extensive and diverse set of 11 spiral galaxies whose data are regarded as being particularly reliable. Without the assumption of the existence of any dark matter the model is found to fit the shapes of the rotation curves extremely well, but with a pattern of normalizations which proves to be very instructive. 
Philip D. Mannheim (University of Connecticut) and Jan Kmetko (Berea   College)