Instanton moduli, topology and the bosonic/heterotic string origins

A bstract We construct new supersymmetric NS(-1)-branes supported by the SU(2) × SU(2) ’t Hooft instantons in 𝒩 = 1, D = 4 supergravity. We show that although the magnetic 3-form string flux is invariant under the variations of instanton moduli, the string-frame metric can change topology, giving rise to either ℝ 4 or the new ℝ × S 3 bolt topologies. We uplift these solutions to both heterotic and bosonic strings, where the instanton moduli become purely geometric parameters. We find that the Killing spinors exist in both theories and their transformation from one theory to the other is consistent with the recently proposed bosonic/heterotic string duality. Furthermore, we construct new BPS solutions in the D = 6 Salam-Sezgin model, employing the techniques developed in the paper.