Probing Gamma-ray Bursts and their Progenitors with Multiwavelength Observations

用多波长观测探测伽马射线暴及其前体

• 批准号: 0098676
• 负责人: Shrinivas Kulkarni
• 金额: $ 25万
• 依托单位: California Institute of Technology
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-08-01 至 2005-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0098676&HistoricalAwards=false
• 关键词: Probing; Gamma; ray; Bursts; their

AST 0098676KulkarniCosmic gamma-ray bursts (GRBs) are among the most spectacular, known phenomena in the universe. They consist of short outbursts (fractions of seconds to a few minutes) of high-energy radiation originating in distant regions of the universe, There are a few such outbursts observed per day. These were first observed by the US Vela satellites in the early 1960's. They have remained one of the major mysteries of astrophysics for the past 30 years. In the late 1990's breakthrough discoveries found that the bursts originated in faint galaxies, at typical distances of several billion light years. Measurements of distances to the bursts, using large, ground-based telescopes, revealed that apparently some of them emit prodigious amounts of energy; larger than the total amount of energy produced by our Sun over its entire projected lifespan of about 10 billion years, but compressed into a few seconds! While theories abound, the ultimate cause of these amazing cosmic explosions remains unknown. However, it now seems likely that at least some bursts represent "birth cries" of black holes, produced in the explosion of massive stars ("hypernovas"). Current research suggests that the GRB phenomenon is closely related to the history of star formation in the universe, and that it can be used as a novel probe of early cosmic evolution. It is also likely that most GRBs produce highly collimated jets of very energetic particles and radiation, effectively becoming giant acceleratorsin the sky. While a lot has been learned over the past few years, much more remains to be found about the source and the ultimate physical mechanism behind these remarkable cosmic explosions. The keys to this further understanding lies in (1) detailed observations of their afterglows seen at wavelengths ranging from radio waves, through visible light and out to x-rays; (2) additional measurements of the distances to these enigmatic events; and (3) a better understanding of their environments and the distant galaxies in which they originate. This is the subject of the presentproject. Using the worlds largest optical/infrared telescopes (the 10-m Keck telescopes in Hawaii and the large telescopes at Mt. Palomar in California), and the world's premier radio telescopes (e.g., the Very Large Array in New Mexico) to observe GRBs when they are first identified and to continue to observe them as they decline in brightness, the goal is to construct a wide enough bank of data to permit testing and winnowing of the scores of theoretical models presently under study. Funding for this project was provided by the NSF program for Extragalactic Astronomy & Cosmology (AST/EXC).***

宇宙伽马射线暴（GRB）是宇宙中最壮观的已知现象之一。 它们由源自宇宙遥远区域的高能辐射的短暂爆发（几秒到几分钟）组成，每天都有一些这样的爆发被观察到。 这些现象最早是在1960年代初由美国的Vela卫星观测到的。在过去的30年里，它们一直是天体物理学的主要谜团之一。在20世纪90年代后期，突破性的发现发现，爆发起源于微弱的星系，典型的距离为数十亿光年。 使用大型地面望远镜对爆发的距离进行测量，发现其中一些爆发显然释放出惊人的能量;比我们的太阳在其整个预计寿命约100亿年内产生的能量总量还要大，但压缩到几秒钟内！ 虽然理论很多，但这些惊人的宇宙爆炸的最终原因仍然未知。 然而，现在看来，至少有一些爆发可能代表了黑洞的“诞生之声”，产生于大质量恒星的爆炸（“超新星”）。 目前的研究表明，伽玛暴现象与宇宙中星星形成的历史密切相关，它可以作为早期宇宙演化的一个新的探针。 大多数伽玛射线暴也可能产生高度准直的高能粒子和辐射射流，有效地成为天空中的巨大加速器。 虽然在过去的几年里已经学到了很多东西，但关于这些非凡的宇宙爆炸背后的来源和最终物理机制，还有更多的东西有待发现。进一步理解的关键在于：（1）对它们的余辉进行详细的观测，其波长范围从无线电波到可见光，再到X射线;（2）对这些神秘事件的距离进行额外的测量;（3）更好地了解它们的环境和它们起源的遥远星系。 这就是本课题的研究对象。 利用世界上最大的光学/红外望远镜（夏威夷的10米凯克望远镜和夏威夷山的大型望远镜），帕洛玛在加州），和世界上首屈一指的射电望远镜（例如，新墨西哥州的甚大阵列），以便在伽玛暴首次被发现时对其进行观测，并在其亮度下降时继续对其进行观测，其目标是建立一个足够广泛的数据库，以便对目前正在研究的大量理论模型进行测试和筛选。该项目的资金由美国国家科学基金会的河外天文宇宙学计划（AST/EXC）提供。