本文選題：伽瑪射線暴 + 高能輻射機(jī)制��； 參考：《南京大學(xué)》2013年博士論文

【摘要】：伽瑪射線暴(簡(jiǎn)稱伽瑪暴)是宇宙中最為猛烈的高能爆發(fā),它是一種隨機(jī)出現(xiàn)的短時(shí)標(biāo)脈沖式現(xiàn)象,自20世紀(jì)60年代被Vela衛(wèi)星發(fā)現(xiàn)以來(lái),一直都是天體物理學(xué)家所關(guān)注的研究熱點(diǎn)。1997年BeppoSAX衛(wèi)星首先發(fā)現(xiàn)了伽瑪暴的余輝,后來(lái)又幫助測(cè)定了伽瑪暴的紅移,因而確定伽瑪暴是起源于宇宙學(xué)距離上的現(xiàn)象�，F(xiàn)在通常認(rèn)為,持續(xù)時(shí)標(biāo)長(zhǎng)于2s的長(zhǎng)暴起源于大質(zhì)量恒星的坍縮,而時(shí)標(biāo)短于2s的短暴來(lái)自雙致密星的并合。對(duì)伽瑪暴的研究可以幫助人們了解極端相對(duì)論、極端高能條件下的物理過程,也可以幫助其他領(lǐng)域的研究,如限制宇宙學(xué)模型等。 本文討論的是伽瑪暴可能的輻射機(jī)制以及瞬時(shí)輻射的光變曲線。由于輻射機(jī)制與瞬時(shí)輻射與爆發(fā)的中心能源直接相關(guān),因此對(duì)它們的研究可以幫助更好地了解中心能源的一些特性。第一章回顧了伽瑪暴的發(fā)現(xiàn)和研究史,簡(jiǎn)要總結(jié)了Compton伽瑪射線天文臺(tái)、BeppoSAX衛(wèi)星、Swift衛(wèi)星、Fermi伽瑪射線太空望遠(yuǎn)鏡等重要的伽瑪暴監(jiān)測(cè)衛(wèi)星得出的成果,并總結(jié)了伽瑪暴瞬時(shí)輻射與余輝的多波段觀測(cè)特性。 第二章介紹了當(dāng)前的伽瑪暴標(biāo)準(zhǔn)模型,即中心能源拋射出火球,火球內(nèi)部速度不同的殼層彼此碰撞,產(chǎn)生內(nèi)激波,將火球定向運(yùn)動(dòng)動(dòng)能轉(zhuǎn)化為內(nèi)能,最終轉(zhuǎn)化為非熱輻射,產(chǎn)生瞬時(shí)輻射；火球與外部介質(zhì)相互作用,產(chǎn)生正反外激波,形成觀測(cè)到的余輝。在此框架下,我們介紹了火球的特性、激波的演化、可能的輻射機(jī)制以及一些后標(biāo)準(zhǔn)效應(yīng),并對(duì)中心能源作了簡(jiǎn)要介紹。另外由于瞬時(shí)輻射的內(nèi)激波模型仍舊存在很多難以解決的問題,我們還介紹了其他幾種可能的瞬時(shí)輻射模型,包括電磁模型、湍流模型、內(nèi)部碰撞誘發(fā)磁重聯(lián)與湍流模型(ICMART)等。 我們?cè)诘谌陆o出了洛侖茲因子以冪律分布的相對(duì)論性電子產(chǎn)生的同步曲率自康普頓(SCSC)輻射的能譜。來(lái)自相對(duì)論性電子環(huán)繞彎曲磁力線運(yùn)動(dòng)的同步曲率輻射及其自康普頓散射是伽瑪暴環(huán)境下可能的輻射機(jī)制。我們發(fā)現(xiàn),如果磁場(chǎng)的曲率半徑以及電子的回旋半徑都具備適當(dāng)?shù)娜≈?同步曲率自康普頓輻射的能譜與同步自康普頓或曲率自康普頓輻射都存在較大差異。為了得到更加精確的圖像,我們還討論了電子的冷卻、電子漂移、種子譜低能自吸收以及散射譜高能Klein-Nishina截?cái)鄬?dǎo)致的影響。我們以伽瑪暴作為我們的討論背景。所得的結(jié)果可以被看作是相對(duì)論性電子在彎曲磁力線環(huán)境下發(fā)生自康普頓散射的統(tǒng)一圖像,可以用于描述許多天體物理現(xiàn)象,包括活動(dòng)星系核(AGN)、脈沖星,也包括伽瑪暴。 我們?cè)诘谒恼轮心M了ICMART模型框架下伽瑪暴的瞬時(shí)輻射光變曲線。這一模型適用于輻射區(qū)的磁化因子σ較大但是又不太大的情形。我們證明,這一模型可以產(chǎn)生變化較大的光變曲線,它具備快慢兩種成分。σ較大的拋射物中湍動(dòng)磁重聯(lián)的過程會(huì)產(chǎn)生諸多的小型輻射元,這些小輻射元被局域多普勒增亮的結(jié)果就是快速光變。每個(gè)ICMART事件磁重聯(lián)隨時(shí)間的雪崩式失控增長(zhǎng)以及隨后小型輻射元的枯竭定義了寬闊的慢成分。一個(gè)伽瑪暴的光變曲線通常由數(shù)個(gè)ICMART事件組成,它們由中心能源的不規(guī)則活動(dòng)驅(qū)動(dòng)。通過改變模型的參數(shù),包括包括初始洛倫茲因子、重聯(lián)區(qū)取向和長(zhǎng)度分布、噴流張角、輻射區(qū)半徑、觀測(cè)能段等,就可以產(chǎn)生觀測(cè)所見形態(tài)與功率譜(PDS)各不相同的光變曲線了。我們還討論了這些參數(shù)對(duì)PDS產(chǎn)生的影響。 最后我們?cè)诘谖逭逻M(jìn)行了討論,并列出了一些有待解決的問題以及即將入役的觀測(cè)儀器。另外我們?cè)诟戒汚與附錄B中分別列出了對(duì)同步曲率輻射以及ICMART模型一些問題的具體推導(dǎo)。
[Abstract]:Gamma - ray bursts ( called gamma - ray bursts ) are the most violent outbreaks in the universe . It is a random short - term pulse phenomenon . Since the discovery of Vela satellites in the 1960s , it has been the focus of astrophysicists .

This paper discusses the possible radiation mechanism of gamma - ray and the curve of transient radiation . Since the radiation mechanism is directly related to the instantaneous radiation and the central energy source of the outbreak , the research of them can help to better understand some of the characteristics of the central energy source . Chapter one reviews the discovery and research history of the Gamma - ray Observatory , summarizes the results of the important gamma - ray monitoring satellites such as the compton gamma - ray observatory , the Beppo4 satellite , the Swift satellite , the Fermi - gamma - ray space telescope and the like , and summarizes the multi - band observation characteristics of the gamma - ray instantaneous radiation and afterglow .

The second chapter introduces the current standard model of gamma storm , that is , the center energy is thrown out of the fireball , the shell layers with different velocities inside the fireball collide with each other , the internal shock wave is generated , the kinetic energy of the directional motion of the fireball is converted into the internal energy , and finally converted into non - thermal radiation to generate instantaneous radiation ;
In this framework , we introduce the characteristics of fireballs , the evolution of shock waves , the possible mechanism of radiation and some post - standard effects , and introduce some other possible transient radiation models , including electromagnetic models , turbulence models , internal collision - induced magnetic reconnection and turbulence models ( ICMART ) .

In chapter 3 , we give the energy spectrum of the synchrotron curvature from the relativistic electron generated by relativistic electron with power law distribution . The synchronous curvature radiation from relativistic electrons around bending magnetic lines and its self - compton scattering are the possible radiation mechanisms . We also discuss the effects of electron cooling , electron drift , low energy self - absorption and high - energy Klein - Nishina truncation . We also discuss the phenomena of electron cooling , electron drift , low energy self - absorption and scattering spectrum high - energy Klein - Nishina truncation .

In chapter 4 , we simulate the transient radiative decay curve of gamma - ray in the framework of ICMART model . The model is suitable for the case of larger but less magnetic factor . We prove that this model can produce many small radiating elements .

In conclusion , we discussed in Chapter V and listed some issues to be resolved and the instruments to be observed . We also listed in Appendix A and Appendix B a detailed derivation of some of the problems with simultaneous curvature radiation and ICMART models , respectively .
【學(xué)位授予單位】：南京大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2013
【分類號(hào)】：P172.3

【共引文獻(xiàn)】

相關(guān)期刊論文 前2條

1 陳海峰;Gamma暴光變曲線主峰特征參量的分布[J];廣西民族學(xué)院學(xué)報(bào)(自然科學(xué)版);2003年02期

2 吳雪峰;陸W，

本文編號(hào)：2046247