Spiral galaxy rotation favors prolate dark matter haloes*

The flattening rotation velocity v(r)→constant found by Rubin and collaborators, and very distinct in the SPARC galaxy rotation data coincides with Kepler's law in one less dimension.  Thus, it is naturally reproduced by filamentary sources of gravity, for example elongated dark matter distributions with the axis of prolateness perpendicular to the galactic plane as we here consider.

This theoretical understanding is borne out by the detailed fits to the rotation data that we report: for equal dark matter profile, elongated distributions provide smaller χ^2 than purely spherical ones.

This is of consequence for the estimated dark matter density near Earth.