Effect of a positive cosmological constant on cosmic strings

We study cosmic Nielsen-Olesen strings in space-times with a positive cosmological constant. For the free cosmic string in a cylindrically symmetric space-time, we calculate the contribution of the cosmological constant to the angle deficit, and to the bending of null geodesics. For a cosmic string in a Schwarzschild–de Sitter space-time, we use Kruskal patches around the inner and outer horizons to show that a thin string can pierce them.