Inferring the Energy and Distance Distributions of Fast Radio Bursts Using the First CHIME/FRB Catalog

Fast radio bursts (FRBs) are brief, energetic, typically extragalactic flashes of radio emission whose progenitors are largely unknown. Although studying the FRB population is essential for understanding how these astrophysical phenomena occur, such studies have been difficult to conduct without large numbers of FRBs and characterizable observational biases. Using the recently released catalog of 536 FRBs published by the Canadian Hydrogen Intensity Mapping Experiment/Fast Radio Burst (CHIME/FRB) collaboration, we present a study of the FRB population that also calibrates for selection effects. Assuming a Schechter function, we infer a characteristic energy cut-off of Echar = 2.38- SIC10 + 5.35 41 erg and a differential power-law index of gamma = 1.3 0.4 --+.Simultaneously, we 0.7 infer a volumetric rate of [7.3+3.8(stat.)SIC0 10 Gpc(-3) yr(-1) above a pivot energy of 1039 erg and below a 4 scattering timescale of 10 ms at 600 MHz, and find we cannot significantly constrain the cosmic evolution of the FRB population with star-formation rate. Modeling the host's dispersion measure (DM) contribution as a lognormal distribution and assuming a total Galactic contribution of 80 pc cm(-3) , we find a median value of DMhost= 84- (+69)(- 49) pc cm(-3) , comparable with values typically used in the literature. Proposed models for FRB progenitors should be consistent with the energetics and abundances of the full FRB population predicted by our results. Finally, we infer the redshift distribution of FRBs detected with CHIME, which will be tested with the localizations and redshifts enabled by the upcoming CHIME/FRB Outriggers project.

Automated summary

Fast radio bursts (FRBs) are brief, energetic, typically extragalactic flashes of radio emission whose progenitors are largely unknown. We used a catalog of 536 FRBs from the CHIME/FRB collaboration to study the FRB population and calibrate for selection effects. Our results provide insights into the energy distribution, density, and redshift distribution of FRBs, and can help constrain models for FRB progenitors. The upcoming CHIME/FRB Outriggers project will further validate our findings by providing localizations and redshifts of FRBs.