Angle deformation of K\"ahler-Einstein edge metrics on Hirzebruch surfaces.

We construct a family of K\"ahler-Einstein edge metrics on all Hirzebruch surfaces using the Calabi ansatz and study their angle deformation. This allows us to verify in some special cases a conjecture of Cheltsov-Rubinstein that predicts convergence towards a non-compact Calabi-Yau fibration in the small angle limit. We also give an example of a K\"ahler-Einstein edge metric whose edge singularity is rigid, answering a question posed by Cheltsov.