No redshift evolution of non-repeating fast radio burst rates

Tetsuya Hashimoto^1,2*, Tomotsugu Goto¹, Alvina Y. L. On^1,2,3, Ting-Yi Lu¹, Daryl Joe D. Santos¹, Simon C.-C. Ho¹, Seong Jin Kim¹, Ting-Wen Wang¹, Tiger Y.-Y. Hsiao¹

¹Institute of Astronomy, National Tsing Hua University, Hsinchu, Taiwan
²Centre for Informatics and Computation in Astronomy, National Tsing Hua University, Hsinchu, Taiwan
³Mullard Space Science Laboratory, University College London, Surrey, UK

* Presenter:Tetsuya Hashimoto, email:tetsuya@phys.nthu.edu.tw

Fast radio bursts (FRBs) are millisecond transients occurring at cosmological distances. Except for one confirmed case, the origin(s) of the remaining >99% of the current FRB sample is still unknown. To overcome this problem, we performed a statistical approach to constrain their progenitors. Here we show, for the first time, number density evolutions of non-repeating and repeating FRBs towards the distant Universe. The number density of non-repeating FRBs is almost constant during the past ~10 Gyr. The nearly-constant density is consistent with a flat trend of cosmic stellar-mass density traced by old stellar populations with ~Gyr time-scales. Our finding strongly narrows down the progenitor candidates of non-repeating FRBs to old objects including white dwarfs, neutron stars, and black holes. In contrast, the number density of repeating FRBs increases towards the distant Universe in a similar way to the cosmic star formation-rate density or supermassive black hole accretion-rate density. Short-living objects with <~Myr time-scales associated with young-stellar populations (or their remnants, e.g., supernova remnants, young pulsars, and magnetars) or active galactic nuclei are progenitor candidates of repeating FRBs. We, for the first time, constrained the progenitors of FRBs statistically, bringing a breakthrough in understanding the origin(s) of FRBs.

Keywords: Astrophysics, Radio continuum transients, Magnetars, Neutron stars, Pulsars