The Fast Radio Burst Population Energy Distribution

We examine the energy distribution of the fast radio burst (FRB) population using a well-defined sample of 63 FRBs from the ASKAP radio telescope, 28 of which are localised to a host galaxy. We apply the luminosity-volume (V/Vₘₐₓ) test to examine the distribution of these transient sources, accounting for cosmological and instrumental effects, and determine the energy distribution for the sampled population over the redshift range 0.01 z 1.02. We find the distribution between 10²³ and 10²⁶J Hz⁻¹ to be consistent with both a pure power-law with differential slope γ=-1.96 ± 0.15, and a Schechter function with γ = -1.82 ± 0.12 and downturn energy Eₘₐₓ ~ 6.3 · 10²⁵J Hz⁻¹. We identify systematic effects which currently limit our ability to probe the luminosity function outside this range and give a prescription for their treatment. Finally, we find that with the current dataset, we are unable to distinguish between the evolutionary and spectral models considered in this work.