本文主要研究内容
作者李龙（2019）在《伽马暴和超新星暴/星周介质密度变化的研究》一文中研究指出：研究表明绝大部分长时标伽马射线暴(简称长暴)都与大质量恒星的死亡有关系。而沃尔夫-拉叶星(大质量恒星演化到后期的一个阶段)最有可能是长暴的前身星,沃尔夫-拉叶星因其自身强劲的星风,导致质量的高速流失,其外层逐渐剥离。因此人们预期长暴的暴周环境会由星风介质向星际介质(Interstellar Medium,简称ISM)转变,形成一个介质密度变化的暴周环境。本工作在分析大量KAIT望远镜的观测数据时,发现GRB 140423A是一个典型的暴周环境由星风介质向星际介质转变的例子:(1)时域分析表明其光学余辉光变曲线早期存在一个平滑的鼓包,随后以指数～1.6幂律衰减,在～5000 s时幂律指数发生了转变,以指数～1.1幂律衰减;X射线余辉的光变曲线从～3000 s开始,同样以指数～1.1幂律衰减。(2)联合Swift/XRT和光学数据进行谱域分析,得到转变时间Tt～5000 s前后的光子谱指数均为-1.90。这表明其光学和X射线余辉可能来自同一起源。本工作进一步采用暴周环境为粒子数密度随半径n(r)∝r-2的星风介质向n(r)∝r0的星际介质转变的外激波模型来检验GRB 140423A的光变特征,模型考虑微观物理参数在转变前后不变,且介质存在密度跳跃。采用MCMC方法进行拟合的结果表明,星风一星际介质转变模型可以解释GRB 140423A的多波段光变曲线并得到一组最佳参数:logεB=-4.42-1.30+1.30,logεe=-1.55-0.37+0.58,log EK,iso=54.38-0.78+0.87 erg,logΓ0=2.54-0.30+0.28，log A*=0.05-1.11+1.10 5 χ=5.22-2.45+2.60,p=2.46-0.27+0.28，log Rt=17.32-0.70+0.67。本工作还基于Swift/XRT和大量光学数据,系统搜寻余辉中具有星风介质向星际介质转变特征的长暴。结果表明:(1)同时具有X射线和光学余辉观测的,只有3个长暴具备星风—星际介质转变特征。(2)工作还得到只有Swift/XRT余辉数据的还有10个长暴符合星风—星际介质模型。对这13个符合星风—星际介质转变模型的长暴的物理参数进行分析发现:①具有星风—星际介质转变特征的伽马暴的各向同性动能量EK,iso在1052到1055 erg之间,电子谱指数p大部分都在2.3左右。②具有星风—星际介质转变特征的伽马暴的喷流张角大都比较大(>10°)。③星风—星际介质转变时间Tt一般在暴后1000—5000秒之间,转换半径Rt在1016到1018 cm之间。本工作同时还研究了超新星星周介质的密度变化。SN 2012aa是一个明亮的Ic型超新星,亮度于普通超新星和超亮超星之间,光变行为十分复杂,用56Ni级联衰变模型、磁星模型、单次相互作用模型均未能解释其热光变曲线中出现第二个鼓包的复杂行为。本工作考虑了密度变化的星周介质所导致的喷射物与星周介质的多次相互作用模型:超新星爆发后的喷射物与先与n(r)∝r2星风相互作用,随后喷射物与n(r)∝r0的致密介质团块相互作用,两次作用分别产生正反激波,激波加热喷射物和星周介质,驱动光变曲线。基于该模型分析能很好解释了其他模型不能解释SN 2012aa峰值后有第二个鼓包的复杂行为,得到其参数为:Mej,i=34.89+62.1991 M(?),Mej,2=36.54M(?),MCSM,1=1.65-0.03+0.02M(?),MCSM,2=15.35-0.49+0.41 M(?),ρCSM,in,1=4.00-0.10+0.10×10-13cm-3,ρCSM,in,2=0.10-0.00+0.01×10-13g cm-3,Rin,1=4.96-0.05+0.03×1014 cm,R in,2=63.21×1014cm,ε1=0.98-0.01+0.01,ε2=0.10-0.00+0.00,tshift,1=8.29-0.12+0.45dya,tshift,2=67.43-1.60+1.67 day。且估算的星风的质量损失率符合预期结果。
Abstract
yan jiu biao ming jue da bu fen chang shi biao ga ma she xian bao (jian chen chang bao )dou yu da zhi liang heng xing de si wang you guan ji 。er wo er fu -la xie xing (da zhi liang heng xing yan hua dao hou ji de yi ge jie duan )zui you ke neng shi chang bao de qian shen xing ,wo er fu -la xie xing yin ji zi shen jiang jin de xing feng ,dao zhi zhi liang de gao su liu shi ,ji wai ceng zhu jian bao li 。yin ci ren men yu ji chang bao de bao zhou huan jing hui you xing feng jie zhi xiang xing ji jie zhi (Interstellar Medium,jian chen ISM)zhuai bian ,xing cheng yi ge jie zhi mi du bian hua de bao zhou huan jing 。ben gong zuo zai fen xi da liang KAITwang yuan jing de guan ce shu ju shi ,fa xian GRB 140423Ashi yi ge dian xing de bao zhou huan jing you xing feng jie zhi xiang xing ji jie zhi zhuai bian de li zi :(1)shi yu fen xi biao ming ji guang xue yu hui guang bian qu xian zao ji cun zai yi ge ping hua de gu bao ,sui hou yi zhi shu ～1.6mi lv cui jian ,zai ～5000 sshi mi lv zhi shu fa sheng le zhuai bian ,yi zhi shu ～1.1mi lv cui jian ;Xshe xian yu hui de guang bian qu xian cong ～3000 skai shi ,tong yang yi zhi shu ～1.1mi lv cui jian 。(2)lian ge Swift/XRThe guang xue shu ju jin hang pu yu fen xi ,de dao zhuai bian shi jian Tt～5000 sqian hou de guang zi pu zhi shu jun wei -1.90。zhe biao ming ji guang xue he Xshe xian yu hui ke neng lai zi tong yi qi yuan 。ben gong zuo jin yi bu cai yong bao zhou huan jing wei li zi shu mi du sui ban jing n(r)∝r-2de xing feng jie zhi xiang n(r)∝r0de xing ji jie zhi zhuai bian de wai ji bo mo xing lai jian yan GRB 140423Ade guang bian te zheng ,mo xing kao lv wei guan wu li can shu zai zhuai bian qian hou bu bian ,ju jie zhi cun zai mi du tiao yue 。cai yong MCMCfang fa jin hang ni ge de jie guo biao ming ,xing feng yi xing ji jie zhi zhuai bian mo xing ke yi jie shi GRB 140423Ade duo bo duan guang bian qu xian bing de dao yi zu zui jia can shu :logεB=-4.42-1.30+1.30,logεe=-1.55-0.37+0.58,log EK,iso=54.38-0.78+0.87 erg,logΓ0=2.54-0.30+0.28，log A*=0.05-1.11+1.10 5 χ=5.22-2.45+2.60,p=2.46-0.27+0.28，log Rt=17.32-0.70+0.67。ben gong zuo hai ji yu Swift/XRThe da liang guang xue shu ju ,ji tong sou xun yu hui zhong ju you xing feng jie zhi xiang xing ji jie zhi zhuai bian te zheng de chang bao 。jie guo biao ming :(1)tong shi ju you Xshe xian he guang xue yu hui guan ce de ,zhi you 3ge chang bao ju bei xing feng —xing ji jie zhi zhuai bian te zheng 。(2)gong zuo hai de dao zhi you Swift/XRTyu hui shu ju de hai you 10ge chang bao fu ge xing feng —xing ji jie zhi mo xing 。dui zhe 13ge fu ge xing feng —xing ji jie zhi zhuai bian mo xing de chang bao de wu li can shu jin hang fen xi fa xian :①ju you xing feng —xing ji jie zhi zhuai bian te zheng de ga ma bao de ge xiang tong xing dong neng liang EK,isozai 1052dao 1055 ergzhi jian ,dian zi pu zhi shu pda bu fen dou zai 2.3zuo you 。②ju you xing feng —xing ji jie zhi zhuai bian te zheng de ga ma bao de pen liu zhang jiao da dou bi jiao da (>10°)。③xing feng —xing ji jie zhi zhuai bian shi jian Ttyi ban zai bao hou 1000—5000miao zhi jian ,zhuai huan ban jing Rtzai 1016dao 1018 cmzhi jian 。ben gong zuo tong shi hai yan jiu le chao xin xing xing zhou jie zhi de mi du bian hua 。SN 2012aashi yi ge ming liang de Icxing chao xin xing ,liang du yu pu tong chao xin xing he chao liang chao xing zhi jian ,guang bian hang wei shi fen fu za ,yong 56Niji lian cui bian mo xing 、ci xing mo xing 、chan ci xiang hu zuo yong mo xing jun wei neng jie shi ji re guang bian qu xian zhong chu xian di er ge gu bao de fu za hang wei 。ben gong zuo kao lv le mi du bian hua de xing zhou jie zhi suo dao zhi de pen she wu yu xing zhou jie zhi de duo ci xiang hu zuo yong mo xing :chao xin xing bao fa hou de pen she wu yu xian yu n(r)∝r2xing feng xiang hu zuo yong ,sui hou pen she wu yu n(r)∝r0de zhi mi jie zhi tuan kuai xiang hu zuo yong ,liang ci zuo yong fen bie chan sheng zheng fan ji bo ,ji bo jia re pen she wu he xing zhou jie zhi ,qu dong guang bian qu xian 。ji yu gai mo xing fen xi neng hen hao jie shi le ji ta mo xing bu neng jie shi SN 2012aafeng zhi hou you di er ge gu bao de fu za hang wei ,de dao ji can shu wei :Mej,i=34.89+62.1991 M(?),Mej,2=36.54M(?),MCSM,1=1.65-0.03+0.02M(?),MCSM,2=15.35-0.49+0.41 M(?),ρCSM,in,1=4.00-0.10+0.10×10-13cm-3,ρCSM,in,2=0.10-0.00+0.01×10-13g cm-3,Rin,1=4.96-0.05+0.03×1014 cm,R in,2=63.21×1014cm,ε1=0.98-0.01+0.01,ε2=0.10-0.00+0.00,tshift,1=8.29-0.12+0.45dya,tshift,2=67.43-1.60+1.67 day。ju gu suan de xing feng de zhi liang sun shi lv fu ge yu ji jie guo 。
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论文详细介绍
论文作者分别是来自广西大学的李龙，发表于刊物广西大学2019-10-14论文，是一篇关于伽马射线暴论文,余辉论文,暴周环境论文,超新星论文,星周介质论文,广西大学2019-10-14论文的文章。本文可供学术参考使用，各位学者可以免费参考阅读下载，文章观点不代表本站观点，资料来自广西大学2019-10-14论文网站，若本站收录的文献无意侵犯了您的著作版权，请联系我们删除。