SIMBAD references

The observed spectral shapes variation and tentative bimodal burst energy distribution (E-distribution) of fast radio burst (FRB) 20121102A with the FAST telescope are great puzzles. Adopting the published multifrequency data observed with the FAST and Arecibo telescopes at L band and the Green Bank Telescope (GBT) at C band, we investigate these puzzles through Monte Carlo simulations. The intrinsic energy function (E-function) is modeled as ${dp}/{dE}\propto {E}^{-{\alpha }_{{\rm{E}}}}$, and the spectral profile is described as a Gaussian function. A fringe pattern of its spectral peak frequency (ν_p) in 0.5-8 GHz is inferred from the ν_p distribution of the GBT sample. We estimate the likelihood of α_E and the standard deviation of the spectral profile (σ_s) by utilizing the Kolmogorov-Smirnov test probability for the observed and simulated specific E-distributions. Our simulations yield ${\alpha }_{{\rm{E}}}={1.82}_{-0.30}^{+0.10}$, and ${\sigma }_{{\rm{s}}}={0.18}_{-0.06}^{+0.28}$ (3σ confidence level) with the FAST sample. These results suggest that a single power-law function is adequate to model the E-function of FRB 20121102A. The variations of its observed spectral indices and E-distributions with telescopes in different frequency ranges are due to both physical and observational reasons, i.e., narrow spectral width for a single burst and discrete ν_p fringe pattern in a broad frequency range among bursts, and the selection effects of the telescope bandpass and sensitivity. The putative ν_p fringe pattern cannot be explained with the current radiation physics models of FRBs. Some caveats of possible artificial effects that may introduce such a feature are discussed.