The afterglow emission from a stratified jet in GRB 170817A

作     者：Kang-Fa Cheng Xiao-Hong Zhao Bin-Bin Zhang Jin-Ming Bai Kang-Fa Cheng;Xiao-Hong Zhao;Bin-Bin Zhang;Jin-Ming Bai

作者机构：Yunnan ObservatoriesChinese Academy of SciencesKunming 650216China University of the Chinese Academy of SciencesBeijing 100049China Center for Astronomical Mega-ScienceChinese Academy of SciencesBeijing 100101China Key Laboratory for the Structure and Evolution of Celestial ObjectsChinese Academy of SciencesKunming 650216China School of Astronomy and Space ScienceNanjing UniversityNanjing 210093China Key Laboratory of Modern Astronomy and Astrophysics(Nanjing University)Ministry of EducationNanjing 210046China Department of Physics and AstronomyUniversity of Nevada Las VegasNV 89154USA 

出 版 物：《Research in Astronomy and Astrophysics》 (天文和天体物理学研究（英文版）)

年 卷 期：2021年第21卷第7期

页      面：223-233页

核心收录：

学科分类：0709[理学-地质学] 07[理学] 0708[理学-地球物理学] 070401[理学-天体物理] 0825[工学-航空宇航科学与技术] 0704[理学-天文学] 

基　　金：supported by the National Natural Science Foundation of China(Nos.U1831135 and 11833003) Yunnan Natural Science Foundation(2014FB188) support by the National Key Research and Development Programs of China(2018YFA0404204) the National Natural Science Foundation of China(grant Nos.11833003 and U2038105) the Program for Innovative Talents,Entrepreneur in Jiangsu 

主　　题：gamma-ray burst:general stars:jets relativistic processes 

摘      要：The afterglow of GRB 170817 A has been detected for more than three years,but the origin of the multi-band afterglow light curves remains under debate.A classical top-hat jet model is faced with difficulties in producing a shallow rise of the afterglow light curves as observed(E_(v) ∝ T^(0.8)).Here we reconsider the model of stratified ejecta with an energy profile of E( Γβ)=E_0(Γβ)^(-k) as the origin of the afterglow light curves of the burst,where Γ and β are the Lorentz factor and speed of the ejecta,respectively.k is the power-law slope of the energy *** consider that the ejecta are collimated into *** kinds of jet evolutions are investigated,including a lateral-spreading jet and a non-lateral-spreading *** fit the multi-band afterglow light curves,including the X-ray data at one thousand days post-burst,and find that both the models of the spreading and non-spreading jets can fit the light curves well,but the observed angular size of the source and the apparent velocity of the flux centroid for the spreading jet model are beyond the observation limits,while the non-spreading jet model meets the observation *** of the best-fit parameters for the non-spreading jet model,such as the number density of the circumburst medium~10^(-2) cm^(-3) and the total jet kinetic energy E ~ 4.8 × 10^(51) erg,also appear *** best-fit slope of the jet energy profile is k ~*** results suggest that the afterglow of GRB 170817 A may arise from the stratified jet and that the lateral spreading of the jet is not significant.