P o S(Bash11)027 The Hunt for the First Supernovae: The Source Density and Observability of Pair-Instability Supernovae from the First Stars

Some of the first stars are expected to have died as extremely energetic pair-instability supernovae (PISNe). With energies approaching 1053 ergs, these supernovae are expected to be within the detection limits of the upcoming James Webb Space Telescope (JWST), allowing us to constrain the properties of these objects for the first time. We estimate the source density of PISNe using a semi-analytic Press-Schechter based approach informed by cosmological simulations including feedback from star formation. We find that the main obstacle to detecting PISNe is their scarcity, not their brightness; exposures longer than a few times 104 s will do little to increase the number of PISNe found. Given this we suggest a mosaic style search strategy for detecting PISNe from the first stars. Even fairly high redshift PISNe are sufficiently bright to be found with moderately deep exposures. However, a large number of pointings will be required to ensure a detection due to their scarcity. For an observing program totalling 106 s, the probability of a detection is maximized by dividing the campaign into ∼150 individual fields with a ∼5000 s exposure in each