Kavli Affiliate: Kiyoshi Masui
| Summary:
Quantifying the maximum energy of fast radio bursts (FRBs) can provide stringent constraints on their emission mechanisms and progenitor models. However, the most energetic bursts are rare, requiring a large sample of FRBs to detect them. In this work, we use the largest available such sample, 2,998 one-off FRBs from the Second CHIME/FRB Catalog, to obtain a lower limit on the maximum energy ($E^mathrmmax_mathrmiso$) of FRBs, assuming isotropic energy distribution from FRB sources. In the absence of known redshifts ($z$) for most sources, we present a framework that uses the dispersion measures (DMs) and fluences of these FRBs, together with the probability distribution of $z$ given DM, to derive the lower limit on $E^mathrmmax_mathrmiso$. We generate simulated FRB samples assuming different parameter values for a log-normal $mathrmDM_mathrmhost$ distribution and a Schechter function form of the FRB energy function to estimate how many outliers — FRBs with large DM contributions from the host galaxy or intervening galaxy halos — could artificially inflate this limit. After accounting for outliers, the lower limit on $E^mathrmmax_mathrmiso$ from Catalog 2 FRBs ranges between $1.2times10^41$ and $1.9times10^42$ erg, with best estimate $1.2times10^42$ erg. This limit is consistent with those derived from much smaller FRB samples. Moreover, inferred energies of hundreds of FRBs appear collectively limited around $sim10^42$ erg, suggesting a physical limit on the energy reservoir of FRB sources. The corresponding isotropic-equivalent FRB source energy is consistent with the total energy available in a magnetar’s external dipole magnetic field, supporting magnetars as FRB progenitors.
| Search Query: arXiv Query: search_query=au:”Masui Kiyoshi”&id_list=&start=0&max_results=10
Read More