Hum,

“Their nice fit to observed rotation curves is faked - they are deriving the glactic density from the rotation curves when they should be doing it the other way around.

2) The theory fails to agree with observations near the galactic centre, which is why observations near the galactic centre have all been left off the graphs.

3) The theory fails miserably and irreconcilably when used in modelling the galactic rotation speeds of dwarf galaxies. You will note that none of the figures in the paper are for dwarf galaxies.

4) The use of "General relativity" is not the reason for their good fit. I can get an equally good fit using Newtonian mechanics.”

source


Singular disk of matter in the Cooperstock and Tieu galaxy model
Authors: Mikolaj Korzynski

Recently a new model of galactic gravitational field, based on ordinary General Relativity, has been proposed by Cooperstock and Tieu in which no exotic dark matter is needed to fit the observed rotation curve to a reasonable ordinary matter distribution. We argue that in this model the gravitational field is generated not only by the galaxy matter, but by a thin, singular disk as well. The model should therefore be considered unphysical.

http://arxiv.org/abs/astro-ph/0508377