String-Seeded Spirals: Origin of Rotation and the Density of the Halo

Galactic halos seeded by loops of string in a universe dominated by dark matter fall into two categories: (1) Non-self-intersecting loops precipitate nearly spherically symmetric collapse and lead to a halo with low angular momentum $J$ and a density profile $\rho \sim r^{-\frac{9}{4}}$. (2) Progeny of a self-intersecting primary loop recollapse into a single object which acquires $J$ through tidal interactions. Its density profile, $\rho \sim r^{-2\mathrm{}}$, is consistent with "flat rotation profiles" observed in spiral galaxies. It is tempting to identify these two types of string-seeded objects with (1) elliptical and (2) spiral galaxies.