中国科学院机构知识库网格
Chinese Academy of Sciences Institutional Repositories Grid
The Time-resolved Spectra of Photospheric Emission from a Structured Jet for Gamma-Ray Bursts

文献类型:期刊论文

作者Meng,Yan-Zhi1,2; Liu,Liang-Duan3,4; Wei,Jun-Jie1; Wu,Xue-Feng1; Zhang,Bin-Bin3,4
刊名The Astrophysical Journal
出版日期2019-08-28
卷号882期号:1
ISSN号0004-637X
关键词gamma-ray burst: general radiation mechanisms: thermal radiative transfer scattering
DOI10.3847/1538-4357/ab30c7
英文摘要Abstract The quasi-thermal components found in many Fermi gamma-ray bursts (GRBs) imply that the photosphere emission indeed contributes to the prompt emission of many GRBs. But whether the observed spectra empirically fitted by the Band function or cutoff power law, especially the spectral and peak energy (Ep) evolutions can be explained by the photosphere emission model alone needs further discussion. In this work, we investigate in detail the time-resolved spectra and Ep evolutions of photospheric emission from a structured jet, with an inner-constant and outer-decreasing angular Lorentz factor profile. Also, a continuous wind with a time-dependent wind luminosity has been considered. We show that the photosphere spectrum near the peak luminosity is similar to the cutoff power-law spectrum. The spectrum can have the observed average low-energy spectral index α?~??1, and the distribution of the low-energy spectral index in our photosphere model is similar to that observed (?2???α???0). Furthermore, the two kinds of spectral evolutions during the decay phase, separated by the width of the core (θc), are consistent with the time-resolved spectral analysis results of several Fermi multi-pulse GRBs and single-pulse GRBs, respectively. Also, for this photosphere model we can reproduce the two kinds of observed Ep evolution patterns rather well. Thus, by considering the photospheric emission from a structured jet, we reproduce the observations well for the GRBs best fitted by the cutoff power-law model for the peak-flux spectrum or the time-integrated spectrum.
语种英语
出版者The American Astronomical Society
WOS记录号IOP:0004-637X-882-1-AB30C7
源URL[http://libir.pmo.ac.cn/handle/332002/27273]  
专题中国科学院紫金山天文台
作者单位1.Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008, People’s Republic of China; xfwu@pmo.ac.cn
2.University of Chinese Academy of Sciences, Beijing 100049, People’s Republic of China
3.School of Astronomy and Space Science, Nanjing University, Nanjing 210093, People’s Republic of China
4.Key Laboratory of Modern Astronomy and Astrophysics (Nanjing University), Ministry of Education, People’s Republic of China
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Meng,Yan-Zhi,Liu,Liang-Duan,Wei,Jun-Jie,et al. The Time-resolved Spectra of Photospheric Emission from a Structured Jet for Gamma-Ray Bursts[J]. The Astrophysical Journal,2019,882(1).
APA Meng,Yan-Zhi,Liu,Liang-Duan,Wei,Jun-Jie,Wu,Xue-Feng,&Zhang,Bin-Bin.(2019).The Time-resolved Spectra of Photospheric Emission from a Structured Jet for Gamma-Ray Bursts.The Astrophysical Journal,882(1).
MLA Meng,Yan-Zhi,et al."The Time-resolved Spectra of Photospheric Emission from a Structured Jet for Gamma-Ray Bursts".The Astrophysical Journal 882.1(2019).

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来源:紫金山天文台

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