Gamma-ray burst (GRB) is the violent explosion of celestial object in the universe. Many GRBs have been observed by Fermi Satellite.

Prof. MAO Jirong and his colleagues from the Yunnan Observatories of the Chinese Academy of Sciences found that the spectral diversities of Fermi GRBs could be explained by the magnetohydrodynamics (MHD) turbulent cascade using the jitter radiation framework. The study was published in The Astrophysical Journal on July 17.

The spectral diversities are shown in the Fermi-observed GRBs. Some GRB spectra are harder, while some GRB spectra are softer. Thus, comprehensive statistics of GRB spectrum is required.

The researchers conducted statistic investigation on the spectral properties of GRBs from Fermi observational sample. The spectral diversities of GRB were clearly presented in their work. It is difficult to explain the GRBs with the softer spectra by inverse Compton scattering or synchrotron self-Compton process. Novel models should be adopted to understand GRB physics.

Random and small-scale magnetic fields are common in the universe. This kind of magnetic fields can be generated by the turbulence in the MHD case. Jitter mechanism is the radiation of the relativistic electrons in the random and small-scale magnetic fields, and the radiation spectrum is determined by the turbulent energy spectrum.

They further utilized the jitter radiation to study the GRB spectral diversities. "Based on the jitter radiation, the GRBs with the softer spectra were explained by the turbulent cascade, and the GRBs with the harder spectra were explained by the inverse turbulent cascade. Therefore, the spectral diversities of Fermi-detected GRBs could be interpreted uniformly by the MHD turbulent cascade," said Prof. MAO.

Both the observational data and theoretical models were considered in this study. The results indicated that the physical processes in the small length-scales and short time-scales take a vital role in the high-energy astrophysical field.