伽玛射线暴与高红移恒星形成率
发布时间：2019-06-09 20:50
【摘要】：伽玛射线暴(简称伽玛暴)是一种伽玛射线辐射突然增强的现象,在宇宙中爆发的方位具有随机性,持续时间从几个毫秒到几千秒不等。早在1967年被美国的军事卫星"Vela"所发现,但出于军事目的,其结果到1973年才公布于众。1991年康普顿卫星的发射,人们开始对伽玛暴有了基本认识。直到1997年"BeppoSAX"卫星的发射与伽玛暴余辉的发现,人们才确认了伽玛暴的宇宙学起源,尤其是光学余辉中超新星成分的发现,更是直接证论了伽玛暴与大质量恒星的塌缩有关。2004年11月,美国航空航天局(NASA)发射了一颗专门用于研究伽玛暴的卫星"Swift".由于其快速定位能力,使人们能够迅速作出反应并测定伽玛暴的红移。"Swift"最大的贡献之一便是它为人们提供了大量的伽玛暴红移样本,从此奠定了伽玛暴作为宇宙学工具的基础。 本文以"Swift"卫星已知红移的伽玛暴样本为基础,第二至四章将研究伽玛暴峰值光度与峰值能量之间的相关性,计算伽玛暴的伪红移,研究伽玛暴光度函数的演化效应,并预言星族Ⅲ恒星存在的可能。此外,本文第五章通过对宇宙红外背景辐射的研究,将进一步对高红移恒星形成率进行限制。 Swift上天后,人们一直致力于研究伽玛暴光度函数的演化问题,但始终没有定论,其中最关键的因素是伽玛暴红移样本的大小。因此,本文第二章主要致力于解决这个问题。伽玛暴红移的测量无非是通过余辉或是宿主星系,然而,就目前而言BAT所触发的近八百个暴中只有不到两百个暴是有观测红移的。显然,这对于研究不同红移范围内伽玛暴的光度函数而言,这个样本仍然太小。本文第二章首先通过已知红移的伽玛暴样本,研究它们某些量之间的经验关系。我们发现,伽玛暴的峰值能量与峰值光度之间存在比较强的相关性。根据这个经验关系,我们估算了近五百个Swift暴的伪红移。第三章,通过这个“扩大”的红移样本拟合不同红移范围内的光度分布,我们发现伽玛暴光度函数与红移之间有明显的演化效应。更让人意想不到的是,我们发现伽玛暴的爆发率与恒星形成率之间的比例系数随红移增大而减小,这完全颠覆了人们之前的认识。 高红移恒星形成率一直是天文学界的研究热点之一,这也是本文研究的另外一个重点,第四和第五章将主要致力于研究解决这个问题。本文将从两个出发点出发：(1)第四章中,首先利用恒星形成率的半解析模型计算星族Ⅰ/Ⅱ和星族Ⅲ的恒星形成历史,通过拟合伽玛暴伪红移分布,对高红移恒星形成率进行限制。然后,根据恒星形成率与CMB光深之间的关系,进一步对星族Ⅲ恒星形成率进行讨论研究。然而,令人意想不到的是我们发现了大量星族Ⅲ恒星伽玛暴存在于Swfit样本中的可能,并估计大概只有1%的星族Ⅲ伽玛暴能被Swift观测到。(2)第五章中,我们先从表象上假设高红移恒星形成率的演化形式与低红移处有类似的情况∝(1+z)a,通过模型计算,我们可以得到星族Ⅰ/Ⅱ与星族Ⅲ恒星占总恒星形成率的比例。而观测上发现近红外波段的背景辐射存在一定的超出现象,目前认为这些超出部分很可能来自高红移的星族Ⅰ/Ⅱ恒星和星族Ⅲ恒星。据此,我们将高红移恒星形成率限制在一个比较平的平台范围内,幂指数0(?)α(?)1。
[Abstract]:The gamma-ray burst (gamma-ray) is a phenomenon of a sudden increase in gamma-ray radiation, which is random in the direction of the explosion in the universe, ranging from several milliseconds to several thousand seconds. It was discovered in 1967 by the American military satellite "Vela", but for military purposes, the results were made public in 1973. In 1991, the Compton satellite's launch started to have a basic understanding of the gamma storm. Until the discovery of the emission of the "The BepoSAX" satellite and the afterglow of the gamma storm in 1997, it was confirmed that the cosmological origin of the gamma-storm, especially the discovery of the supernova component in the optical afterglow, was related to the collapse of the gamma-storm and the mass star. In November,2004, NASA has launched a satellite "Swift" dedicated to the study of gamma-storm. As a result of its rapid positioning ability, it is possible to react quickly and to determine the red shift of the gamma storm. One of the most important contributions of the "Swift" is that it provides a large number of gamma-exposure samples to people, laying the foundation for gamma-storm as a cosmic tool. On the basis of the known red-shift gamma-storm samples of the "Swift" satellite, the second to four chapters will study the correlation between the peak luminosity and the peak energy of the gamma-storm, calculate the pseudo-red shift of the gamma-burst, study the evolution effect of the gamma-storm photometric function, and predict the existence of the star-III stars. In addition, Chapter 5 of this paper will further limit the formation rate of the high-red-shift star by studying the radiation of the infrared background of the universe. With Swift, people have been working to study the evolution of the gamma-ray function, but there is no doubt that the most critical factor is the gamma-red-shift sample. Therefore, the second chapter of this article is mainly devoted to solving this problem A problem. The gamma-red-shift measurement is only through the afterglow or the host galaxy. However, only less than two hundred of the nearly eight hundred and most of the's that are currently triggered by BAT are observed. Red shift. It is clear that this sample is still for the photometric function of the gamma-storm in different red-shift ranges The second chapter of this article first, through the known red-shift gamma-storm sample, studies the passage between some of them. We found that there is a strong correlation between the peak energy of the gamma storm and the peak value. The relationship. Based on this empirical relationship, we have estimated nearly 500 Swift storms. Pseudo-red shift. In chapter 3, by fitting the red-shift sample of this "expand" to the photometric distribution in the range of red-shift, we find that there is a clear play between the gamma-gamma function and the red shift. What's more, we find that the ratio of the burst rate of the gamma storm to the star formation rate decreases with the increase of the red shift, which completely subverts the people The high-red-shift star formation rate has been one of the hot spots in the field of astronomy, and this is another key point in this paper. The fourth and the fifth chapter will focus on the research. This paper is based on two starting points: (1) In the fourth chapter, the star formation history of the star group I/ 鈪，
本文编号：2495889
[Abstract]:The gamma-ray burst (gamma-ray) is a phenomenon of a sudden increase in gamma-ray radiation, which is random in the direction of the explosion in the universe, ranging from several milliseconds to several thousand seconds. It was discovered in 1967 by the American military satellite "Vela", but for military purposes, the results were made public in 1973. In 1991, the Compton satellite's launch started to have a basic understanding of the gamma storm. Until the discovery of the emission of the "The BepoSAX" satellite and the afterglow of the gamma storm in 1997, it was confirmed that the cosmological origin of the gamma-storm, especially the discovery of the supernova component in the optical afterglow, was related to the collapse of the gamma-storm and the mass star. In November,2004, NASA has launched a satellite "Swift" dedicated to the study of gamma-storm. As a result of its rapid positioning ability, it is possible to react quickly and to determine the red shift of the gamma storm. One of the most important contributions of the "Swift" is that it provides a large number of gamma-exposure samples to people, laying the foundation for gamma-storm as a cosmic tool. On the basis of the known red-shift gamma-storm samples of the "Swift" satellite, the second to four chapters will study the correlation between the peak luminosity and the peak energy of the gamma-storm, calculate the pseudo-red shift of the gamma-burst, study the evolution effect of the gamma-storm photometric function, and predict the existence of the star-III stars. In addition, Chapter 5 of this paper will further limit the formation rate of the high-red-shift star by studying the radiation of the infrared background of the universe. With Swift, people have been working to study the evolution of the gamma-ray function, but there is no doubt that the most critical factor is the gamma-red-shift sample. Therefore, the second chapter of this article is mainly devoted to solving this problem A problem. The gamma-red-shift measurement is only through the afterglow or the host galaxy. However, only less than two hundred of the nearly eight hundred and most of the's that are currently triggered by BAT are observed. Red shift. It is clear that this sample is still for the photometric function of the gamma-storm in different red-shift ranges The second chapter of this article first, through the known red-shift gamma-storm sample, studies the passage between some of them. We found that there is a strong correlation between the peak energy of the gamma storm and the peak value. The relationship. Based on this empirical relationship, we have estimated nearly 500 Swift storms. Pseudo-red shift. In chapter 3, by fitting the red-shift sample of this "expand" to the photometric distribution in the range of red-shift, we find that there is a clear play between the gamma-gamma function and the red shift. What's more, we find that the ratio of the burst rate of the gamma storm to the star formation rate decreases with the increase of the red shift, which completely subverts the people The high-red-shift star formation rate has been one of the hot spots in the field of astronomy, and this is another key point in this paper. The fourth and the fifth chapter will focus on the research. This paper is based on two starting points: (1) In the fourth chapter, the star formation history of the star group I/ 鈪，
本文编号：2495889
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