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Title: Extremely Bright GRB 160625B with Multiple Emission Episodes: Evidence for Long-term Ejecta Evolution

Abstract

GRB 160625B is an extremely bright GRB with three distinct emission episodes. By analyzing its data observed with the Gamma-Ray Burst Monitor (GBM) and Large Area Telescope (LAT) on board the Fermi mission, we find that a multicolor blackbody (mBB) model can be used to fit very well the spectra of the initial short episode (Episode I) within the hypothesis of photosphere emission of a fireball model. The time-resolved spectra of its main episode (Episode II), which was detected with both GBM and LAT after a long quiescent stage (∼180 s) following the initial episode, can be fitted with a model comprising an mBB component plus a cutoff power-law (CPL) component. This GRB was detected again in the GBM and LAT bands with a long extended emission (Episode III) after a quiescent period of ∼300 s. The spectrum of Episode III is adequately fitted with CPL plus single power-law models, and no mBB component is required. These features may imply that the emission of the three episodes are dominated by distinct physics processes, i.e., Episode I is possible from the cocoon emission surrounding the relativistic jet, Episode II may be from photosphere emission and internal shock of the relativistic jet,more » and Episode III is contributed by internal and external shocks of the relativistic jet. On the other hand, both X-ray and optical afterglows are consistent with the standard external shocks model.« less

Authors:
; ; ; ; ; ; ;  [1];  [2]
  1. Guangxi Key Laboratory for Relativistic Astrophysics, Department of Physics, Guangxi University, Nanning 530004 (China)
  2. School of Physics, Huazhong University of Science and Technology, Wuhan 430074 (China)
Publication Date:
OSTI Identifier:
22679700
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 849; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; AFTERGLOW; COSMIC GAMMA BURSTS; EMISSION; FIREBALL MODEL; GAMMA RADIATION; HYPOTHESIS; NUCLEAR FIREBALLS; PHOTOSPHERE; RELATIVISTIC RANGE; SPECTRA; STAR EVOLUTION; TELESCOPES; TIME RESOLUTION; X RADIATION

Citation Formats

Lü, Hou-Jun, Lü, Jing, Zhong, Shu-Qing, Huang, Xiao-Li, Zhang, Hai-Ming, Lan, Lin, Lu, Rui-Jing, Liang, En-Wei, and Xie, Wei, E-mail: lhj@gxu.edu.edu, E-mail: lew@gxu.edu.cn. Extremely Bright GRB 160625B with Multiple Emission Episodes: Evidence for Long-term Ejecta Evolution. United States: N. p., 2017. Web. doi:10.3847/1538-4357/AA8F99.
Lü, Hou-Jun, Lü, Jing, Zhong, Shu-Qing, Huang, Xiao-Li, Zhang, Hai-Ming, Lan, Lin, Lu, Rui-Jing, Liang, En-Wei, & Xie, Wei, E-mail: lhj@gxu.edu.edu, E-mail: lew@gxu.edu.cn. Extremely Bright GRB 160625B with Multiple Emission Episodes: Evidence for Long-term Ejecta Evolution. United States. doi:10.3847/1538-4357/AA8F99.
Lü, Hou-Jun, Lü, Jing, Zhong, Shu-Qing, Huang, Xiao-Li, Zhang, Hai-Ming, Lan, Lin, Lu, Rui-Jing, Liang, En-Wei, and Xie, Wei, E-mail: lhj@gxu.edu.edu, E-mail: lew@gxu.edu.cn. Wed . "Extremely Bright GRB 160625B with Multiple Emission Episodes: Evidence for Long-term Ejecta Evolution". United States. doi:10.3847/1538-4357/AA8F99.
@article{osti_22679700,
title = {Extremely Bright GRB 160625B with Multiple Emission Episodes: Evidence for Long-term Ejecta Evolution},
author = {Lü, Hou-Jun and Lü, Jing and Zhong, Shu-Qing and Huang, Xiao-Li and Zhang, Hai-Ming and Lan, Lin and Lu, Rui-Jing and Liang, En-Wei and Xie, Wei, E-mail: lhj@gxu.edu.edu, E-mail: lew@gxu.edu.cn},
abstractNote = {GRB 160625B is an extremely bright GRB with three distinct emission episodes. By analyzing its data observed with the Gamma-Ray Burst Monitor (GBM) and Large Area Telescope (LAT) on board the Fermi mission, we find that a multicolor blackbody (mBB) model can be used to fit very well the spectra of the initial short episode (Episode I) within the hypothesis of photosphere emission of a fireball model. The time-resolved spectra of its main episode (Episode II), which was detected with both GBM and LAT after a long quiescent stage (∼180 s) following the initial episode, can be fitted with a model comprising an mBB component plus a cutoff power-law (CPL) component. This GRB was detected again in the GBM and LAT bands with a long extended emission (Episode III) after a quiescent period of ∼300 s. The spectrum of Episode III is adequately fitted with CPL plus single power-law models, and no mBB component is required. These features may imply that the emission of the three episodes are dominated by distinct physics processes, i.e., Episode I is possible from the cocoon emission surrounding the relativistic jet, Episode II may be from photosphere emission and internal shock of the relativistic jet, and Episode III is contributed by internal and external shocks of the relativistic jet. On the other hand, both X-ray and optical afterglows are consistent with the standard external shocks model.},
doi = {10.3847/1538-4357/AA8F99},
journal = {Astrophysical Journal},
number = 1,
volume = 849,
place = {United States},
year = {Wed Nov 01 00:00:00 EDT 2017},
month = {Wed Nov 01 00:00:00 EDT 2017}
}