当前位置:主页 > 科技论文 > 天文学论文 >

伽玛射线暴与奇异星

发布时间:2020-03-31 05:26
【摘要】:In this PhD thesis. I mainly discuss two topics: Strange Stars (SSs) and Gamma-Ray Bursts (GRBs).The concept of neutron star is proposed as early as in the 1930s, and pulsars were discovered and identified as neutron stars in the late sixties. To many people this identification is quite convincing, and it is always regarded as a good example of a successful identification in modern astrophysics. However, we should be aware that pulsars may not, be neutron stars at all, they muy be Strange Stars. This possibility stems from the hypothesis proposed by Witten and Farhi Jaffe in 1984: the absolute ground state of hadrons might bo strange quark matter (i.e., the energy state of strange stars may be lower than that of neutron stars for rather wide range of QCD paramelers). This conjecture is of obvious importance to modern physics, and has attracted a lot, of attentions. In 1991, a successful international workshop on strange quark matter was held in Denmark. Today, scientists all over the world are still Irving hard to resolve this problem through laboratory experiments and/or astrophysical tests.Gamma-ray bursts (GRBs) have puzzled astronomers since their accidental discoveryin the late sixties. The BATSE detector onboard the Compton-GRO satellite has been detecting one burst per day for the last six years. Its findings have revolutionized our ideas about the nature of these objects. They have shown that GRBs are at cosmological distances. This idea was accepted with difficulties at first. The recent discovery of X-ray, optical and radio afterglows from some GRBs due to the Italian/Dutch satellite BeppoSAX has strongly confirmed the cosmologieal origin. Cosmologieal GRBs release ~ 10~(50) 10~(54)crgs in a few seconds, making them the most (electromagnetically) luminous objects in the Universe. The simplest, most conventional, and practically inevitable, interpretation of these observations is that GRBs result from the conversion of the kinetic energy of ultra-relativistic particles or possibly the electromagnetic energy of a Poynting flux to radiation in an optically thin region. This generic "fireball" model has also been confirmed by the afterglow observations. The "inner engine" of GRB is well hidden from direct observations, but we still could infer some hints.Currently SSs and GRBs arc very active areas in high energy astrophysics. Under the direction of Professor Lu Tan, together with other collaborators in our group. I have done some researches in these fields and published several papers in astrophysical journals. They include: two papers in AA;one in ApJ;one in MXRAS;three in Chinese Physics Letters;and two in other Chinese journals. Some of these results have been cited by other researchers. I present some of our lindings in this thesis, of which the structure and the contents are sketched as follows:Chapter 1 is a brief review on strange stars. The history, the physical background. the dynamics of strange quark matter, the so called strange dwarfs, the difference between strange stars and neutron stars, and many other related astrophysics are brielly introduced. Chapter 2 discusses I.he normal matter crusts of SSs. This chapter is mainly basedon oik1 of our rcbcareheb: we have developed a self-consistent model to depict the electric, field at the snrfa.ro of a SS, wn find that t.lir maximum curst density is only about one lil'lh of the usually assumed neutron drip density. Detailed results have b:t,'ii published in AA (19D7) mid Chinebe Phybics Letters (1997). These results ha\e already boon cited by Jos Madden.Chapter 3 is a. brief introduction to CRBs. Emphasis is put on the recent progresses, i.e.. GRR afterglow observations and the rosmologioal firoball model.Chapter 4 discusses the post-burst evolution of adiabatic GRB remumitb. We liavo evaluated the process numerically, anil find that the remnant will cease to be highly rolativistic several days after the main GRB. So we need lo imosligate the marginally relativistie phase. The results have been published in MNR.AS (1998).Chapter 5 discusses afterglows from Soft Gamma Repeal,crs. We suggest thai, we could test the fireball model by monitoring X-ray and optical i-ifteriilowb from Soft Gamma Repeaters. Detailed results were published in Cliinrsr Physics Letters (1998) and Journal of Nanjing University (1998).Chapter fi studies tlie evolution of a.diaba.tir GRR remnants. Emphasis has been put on the transition from the highh relativisiie phase to the iion-rclativistic phase. which, according to our calculation, should happen much earlier than previously exported. The results have been published in AA (Lett.) (1998). Our results were cited by Meszaros. Roes and Wijors.Chapter 7 studies afterglows from ''realistic" GRB remnants. The remnant evolves from highly radiative stage to a.diaba.tir. stage. We dovelopo a dynamical model to describe this process. The results have been accepted for publication in ApJ.Chapter S developos a "generic" dynamir.al model for GRR remnants, i.e.. the model is applicable to bol.h radiative and adiabatie blast,waves, in both relativistie and non-relativibtic phases. The results have been i-iccepted for publication in Chinese Physics Letters and/or submitted to Y1NRAS.Chapter 9 is a brief summary of the whole thesib. I personally believe tin-it the most confusing enigma of GRRs, the "inner engine", might bo closely related to SSs.In short, in this thesis, in addition lo the necessary reviews on SSs (chapter 1) and GRBb (Chapter 3). I mainly present my own researches in these fields. My interests are concentrated in two aspects: (i) 1 study I,he maximum density of SS crusts and lind that previous models did not satisfy the mechanical balance condition. After considering this condition, the maximum density should only be about one fifth of the neutron drip density (4.3 x 10u g riu"1') (Chapter 2): (ii) 1 sl.udy the general ease of the dynamical evolution of GRB remumitb. which may be either highly radiative or adiabatic, ultra-relative tic or non-relalivistic (Chapter 4 8). 1 compare my results with observations and lind that the fireball model agrees with observation:? quite well.
【学位授予单位】:南京大学
【学位级别】:博士
【学位授予年份】:1999
【分类号】:P144

【相似文献】

相关期刊论文 前10条

1 黄永锋;;2008南京伽玛射线暴会议[J];国际学术动态;2009年04期

2 林达斌;;梁恩维教授和他的科研团队——从宇宙伽玛射线暴说起[J];玉林师范学院学报;2017年02期

3 马涛;常进;张南;蔡明生;宫一忠;唐和森;张仁健;王楠森;于敏;胡一鸣;;嫦娥二号伽玛射线谱仪[J];天文学报;2013年03期

4 刘永志;伽玛射线对付豆类致人放屁[J];大豆通报;2002年04期

5 王守茂;密闭管道中采用伽玛射线进行液位测量[J];物理实验;2001年03期

6 ;宇宙伽玛射线爆发的原因有待重新解释[J];世界科技研究与发展;1997年01期

7 苏杨;;辐射育成大丽花新品种[J];中国花卉盆景;1989年Z2期

8 П.С.巴拉克;М.Б.拉巴波尔特;蓝本洁;;沉积岩对伽玛射线的吸收[J];地球物理勘探;1957年04期

9 希;;探测来自宇宙的伽玛射线[J];世界科学;1984年02期

10 徐永煊;;伽玛射线暴[J];大自然探索;2009年04期

相关会议论文 前10条

1 戴子高;;伽玛射线暴与相关物理过程的最新研究[A];中国天文学会2015年学术年会摘要集[C];2015年

2 王祥玉;;伽玛射线暴的高能光子和粒子辐射[A];新观点新学说学术沙龙文集34:高能天体物理中的热点问题[C];2009年

3 刘当波;陈磊;尤峻汉;;双光子湮灭吸收的匹配条件及其在伽玛射线天文中的应用[A];中国天文学会高能分会2004年学术年会论文集[C];2004年

4 周明;;河外伽玛射线背景的起源[A];中国天文学会2011年学术年会手册[C];2011年

5 邵琅;;伽玛射线暴的时变分析研究进展[A];2013中国天文学会学术年会文集[C];2013年

6 黄永锋;陆W,

本文编号:2608632


资料下载
论文发表

本文链接:https://www.wllwen.com/kejilunwen/tianwen/2608632.html


Copyright(c)文论论文网All Rights Reserved | 网站地图 |

版权申明:资料由用户d1731***提供,本站仅收录摘要或目录,作者需要删除请E-mail邮箱bigeng88@qq.com