The first supernovae: Source density and observability of pair instability supernovae

Theoretical models predict that some of the first stars ended their lives as extremely energetic Pair Instability Supernovae (PISNe). With energies approaching 1053 erg, these supernovae are expected to be within the detection limits of the upcoming James Webb Space Telescope (JWST) allowing observational constraints to be placed on the properties of the first stars. We estimate the source density of PISNe using a semi-analytic Press-Schecter based approach informed by cosmological simulations, with an upper limit of ∼0.2 PISNe visible per JWST field of view at any given time. We find that the main obstacle to observing PISNe is their scarcity rather than their faintness. Given this we suggest a mosaic style search strategy for detecting PISNe from the first stars.