Dark companion of baryonic matter
  Whenever and wherever one talks of dark matter, one does so when and where there is a luminous matter and a dynamical issue to be settled. We promote this observation to the status of an axiom and assume that there is a dark companion to every luminous matter and there are orders to this companionship. To pursue the proposition in a formal and quantitative manner, we consider the anomalous rotation curves of spiral galaxies. From the available observations, we infer the gravitational potential prevailing in the outer parts of the galaxy and, thereof, construct the tt- component of the metric of the embedding spacetime. Next we examine a perfect fluid candidate as the dark companion and solve the relevant GR equations. We are able to determine the strength and the distribution of the dark fluid that accompanies a point baryonic mass. Finally, we argue that the whole paradigm can be explained just as well in terms of an alternative theory.   Keywords: Dark matter; Alternative GR; Spiral galaxies, rotation curves of 
Yousef Sobouti