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 with his colleagues in Yunnan Observatories of Chinese academy of sciences, find the spectral diversities of Fermi GRBs can be explained by the magnetohydrodynamics (MHD) turbulent cascade using the jitter radiation framework. The result is published in The Astrophysical Journal recently.

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.

Prof. MAO and his collaborators performed statistic investigation to the spectral properties of GRBs from Fermi observational sample. The spectral diversities of GRB are 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 utilize the jitter radiation to study the GRB spectral diversities. Based on the jitter radiation, the GRBs with the softer spectra are explained by the turbulent cascade, and the GRBs with the harder spectra are explained by the inverse turbulent cascade. Therefore, the spectral diversities of Fermi-detected GRBs can be interpreted uniformly by the MHD turbulent cascade.

Prof. MAO has worked on the radiation mechanisms in the high-energy astrophysical field during recent years. Both observational data and theoretical models are considered in this study. The new results mentioned above indicate that the physical processes in the smalllengthscale and short timescales take a vital role in the high-energy astrophysical field.

Contact:

MAO Jirong, YNAO, CAS
Jirongmao@mail.ynao.ac.cn