首页|Time-resolved Spectral Properties of Fermi-GBM Bright Long Gamma-Ray Bursts

Time-resolved Spectral Properties of Fermi-GBM Bright Long Gamma-Ray Bursts

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The prompt emission mechanism of gamma-ray bursts(GRBs)is still unclear,and the time-resolved spectral analysis of GRBs is a powerful tool for studying their underlying physical processes.We performed a detailed time-resolved spectral analysis of 78 bright long GRB samples detected by Fermi/Gamma-ray Burst Monitor.A total of 1490 spectra were obtained and their properties were studied using a typical Band-shape model.First,the parameter distributions of the time-resolved spectrum are given as follows:the low-energy spectral index α～-0.72,high-energy spectral index β～-2.42,the peak energy Ep～221.69 keV,and the energy flux F～7.49 × 10-6erg cm-2s-1.More than 80％ of the bursts exhibit the hardest low-energy spectral index αmax exceeding the synchrotron limit(-2/3).Second,the evolution pattems of α and Ep were statistically analyzed.The results show that for multi-pulse GRBs the intensity-tracking pattern is more common than the hard-to-soft pattem in the evolution of both Ep and α.The hard-to-soft pattern is generally shown in single-pulse GRBs or in the initial pulse of multi-pulse GRBs.Finally,we found a significant positive correlation between F and Ep,with half of the samples exhibiting a positive correlation between F and α.We discussed the spectral evolution of different radiation models.The diversity of spectral evolution pattems indicates that there may be more than one radiation mechanism occurring in the GRB radiation process,including photospheric radiation and synchrotron radiation.However,it may also involve only one radiation mechanism,but more complicated physical details need to be considered.

(stars:)gamma-ray burst:generalmethods:statisticalmethods:data analysis

Wan-Kai Wang、Wei Xie、Zhi-Fu Gao、Shuo Xiao、Ai-Jun Dong、Bin Zhang、Qi-Jun Zhi

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Department of Astronomy,School of Physics and Electronic Science,Guizhou Normal University,Guiyang 550001,China

Guizhou Provincial Key Laboratory of Radio Astronomy Data Processing,Guizhou Normal University,Guiyang 550001,China

Xinjiang Astronomical Observatory,Chinese Academy of Sciences,Urumqi 830011,China

Science and Technology Foundation of Guizhou ProvinceMajor Science and Technology Program of Xinjiang Uygur Autonomous Region国家重点研发计划国家自然科学基金国家自然科学基金国家自然科学基金

QianKeHeJiChu ZK[2021]0272022A03013-12022YFC2205202122881021204130411847102

2024

10.1088/1674-4527/ad16af

天文和天体物理学研究
中国科学院国家天文台

天文和天体物理学研究

CSTPCD
影响因子：0.406
ISSN：1674-4527
年,卷(期)：2024.24(2)
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