Fermi Observations of GRB 220426A: a burst similar to GRB 090902B
| Autor: | Deng, Li-Tao, Lin, Da-Bin, Zhou, Li, Wang, Kai, Yang, Xing, Hou, Shu-Jin, Li, Jing, Wang, Xiang-Gao, Lu, Rui-Jing, Liang, En-Wei |
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| Rok vydání: | 2022 |
| Předmět: | |
| Druh dokumentu: | Working Paper |
| Popis: | We report on a very bright, long-duration gamma-ray burst (GRB), GRB~220426A, observed by \emph{Fermi} satellite. GRB~220426A with total duration of $T_{90}=6$~s is composed with two main pulses and some sub-peaks. The spectral analysis of this burst with Band function reveals that both the time-integrated and the time-resolved spectra are very narrow with high $\alpha \gtrsim 0.2$ and low $\beta\lesssim -3.1$. It is strong reminiscent of GRB~090902B, a special GRB with identification of the photospheric emission. Then, we perform the spectral analysis of this burst based on a non-dissipated photospheric emission, which can be well modelled as the multicolor-blackbody with a cutoff power-law distribution of the thermal temperature. The spectral fittings reveal that the photospheric emission can well describe the radiation spectrum of this burst. We conclude that this burst would be a second burst in the class of GRB~090902B observed by \emph{Fermi} satellite. We also discuss the physics of photosphere and the origin of the high-energy component in GRB~220426A . Comment: 11 pages, 6 figures, 1 table |
| Databáze: | arXiv |
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