A local Lorentzian Ferrand-Obata theorem for conformal vector fields

For a conformal vector field on a closed, real-analytic, Lorentzian manifold we prove that the flow is locally isometric -- that it preserves a metric in the conformal class on a neighborhood of any point -- or the metric is everywhere conformally flat.

The main theorem can be viewed as a local version of the Lorentzian Lichnerowicz conjecture in the real-analytic setting.

The key result is an optimal improvement of the local normal forms for conformal vector fields of [FM13], which focused on non-linearizable singularities.

This article is primarily concerned with essential linearizable singularities, and the proofs include global arguments which rely on the compactness assumption.