  The hybrid Ricci scalar $R_{\mu\nu}\eta^{\mu\nu}$ formed from a
Robertson-Walker derived Ricci tensor and a distinct flat space metric becomes
a dark, pseudo-isothermal density under asymptotic constraint. While extension
of this constraint to more general scenarios is unclear, it is model
independent and suggestive of a radical premise: all galactic dark matter halos
are sourced by very many distinct Robertson-Walker spacetimes. We explore this
premise and present a cored galactic halo, which encloses finite mass over all
space. We compute fit parameters to published data on the Milky Way dwarf
spheroidal galaxies, and find consistency with a predicted reciprocal square
scaling relation. Spherical symmetry permits treatment of each individual halo
as a point particle interacting under a modified gravitational force. This
force is Newtonian at large separation with a leading dipole correction, and
naturally softens to zero at small separation. Taken as cold dark matter,
ensembles of such halos present a possible resolution to tension between
large-scale $N$-body simulations and small-scale astrophysical data.
