We construct a global geometric model for the bosonic sector and Killing spinor equations of four-dimensional N= 1 supergravity coupled to a chiral non-linear sigma model and a Spin0c structure. The model involves a Lorentzian metric g on a four-manifold M, a complex chiral spinor and a map φ: M→ M from M to a complex manifold M endowed with a novel geometric structure which we call a chiral triple. Using this geometric model, we show that if M is spin then the Kähler-Hodge condition on M suffices to guarantee the existence of an associated N= 1 chiral geometric supergravity. This positively answers a conjecture proposed by D. Z. Freedman and A. V. Proeyen. We dimensionally reduce the Killing spinor equations to a Riemann surface X, obtaining a novel system of partial differential equations for a harmonic map with potential φ: X→ M. We characterize all Riemann surfaces X admitting supersymmetric solutions with vanishing superpotential, showing that such solutions φ are holomorphic maps satisfying a certain condition involving the canonical bundle of X and the chiral triple of the theory. Furthermore, we determine the biholomorphism type of all Riemann surfaces carrying supersymmetric solutions with complete Riemannian metric and finite-energy scalar map φ.
We construct a global geometric model for the bosonic sector and Killing spinor equations of four-dimensional $\mathcal{N}=1$ supergravity coupled to a chiral non-linear sigma model and a Spin$^{c}_0$ structure. The model involves a Lorentzian metric $g$ on a four-manifold $M$, a complex chiral spinor and a map $\varphi\colon M\to \mathcal{M}$ from $M$ to a complex manifold $\mathcal{M}$ endowed with a novel geometric structure which we call chiral triple. Using this geometric model, we show that if $M$ is spin the K\"ahler-Hodge condition on a complex manifold $\mathcal{M}$ is enough to guarantee the existence of an associated $\mathcal{N}=1$ chiral geometric supergravity, positively answering a conjecture proposed by D. Z. Freedman and A. V. Proeyen. We dimensionally reduce the Killing spinor equations to a Riemann surface $X$, obtaining a novel system of partial differential equations for a harmonic map with potential $\varphi\colon X\to \mathcal{M}$ from $X$ into the K\"ahler moduli space $\mathcal{M}$ of the theory. We characterize all Riemann surfaces admitting supersymmetric solutions with vanishing superpotential, proving that they consist on holomorphic maps of Riemann surfaces into $\mathcal{M}$ satisfying certain compatibility condition with respect to the canonical bundle of $X$ and the chiral triple of the theory. Furthermore, we classify the biholomorphism type of all Riemann surfaces carrying supersymmetric solutions with complete Riemannian metric and finite-energy scalar map.