Gamma ray burst astrophysics

在20世纪60年代末被发现后的大约30年里，伽马射线爆发一直是天文学上最大的谜团之一。伽马射线暴的位置最终被定位到足够精确的位置，以寻找X射线和光学余辉，并在20世纪90年代末确定它们起源的星系。2004年，美国宇航局的斯威夫特天文台发射升空，它在伽马射线爆发发生时自动定位伽马射线爆发，并在90秒内旋转，使其光学/紫外望远镜和X射线望远镜在爆发后几分钟内捕获余辉。我们现在知道，长伽马射线爆发（持续时间超过2秒）发生在终结大质量恒星生命的超新星爆炸中，而短伽马射线爆发可能来自中子星星双星的合并。爆炸和随后的余辉的物理学是争论的热点。雨燕与地面望远镜和其他太空观测站一起，提供了大量关于伽马射线爆发及其余辉的数据。Swift上的光学/紫外线望远镜（UVOT）是在MSSL设计和建造的，我们拥有一个在Swift天文台发挥重要作用的运营团队，分析伽马射线暴数据，因为它来自斯威夫特。这个项目是一个博士生一起工作，我们的业务团队在研究伽马-射线爆发，并利用大量的UVOT数据来进一步了解这些惊人的爆炸的物理学：它们是如何被驱动的，相对论性爆炸波如何将能量沉积到周围的介质中，伽马射线爆发发生的环境，祖先恒星可能是什么，以及伽玛射线暴告诉我们关于星星和星系形成的宇宙历史。学生将研究伽马射线和光学能量学之间的相关性，建立在我们最近发现的余辉亮度和衰减速度之间的相关性上（Oates，Page et al. 2012，MNRAS 426，L26）。学生还将在Swift探测到伽马射线暴的最初几分钟内体验伽马射线暴的实时调查和跟踪，并有机会详细研究学生值班时发生的任何异常暴。学生将对这些爆炸的物理学有一个第一线的理解，并有助于提高这种理解。

For around 30 years after their discovery in the late 1960s, gamma-ray bursts were one of astronomy's biggest mysteries. The locations of gamma ray bursts were finally localised with enough precision to search for X-ray and optical afterglows, and identify the galaxies in which they originate, in the late 1990s. In 2004, NASA's Swift observatory was launched, which localises gamma ray bursts autonomously as they are happening, and slews within 90 seconds to bring its Optical/UV Telescope and X-ray Telescope to capture the afterglow within a few minutes of the burst. We now know that long gamma-ray bursts (with durations longer than 2 seconds) occur in the hypernova explosions that end the lives of massive stars, and that the short gamma-ray bursts are likely to come from the merging of neutron star binaries. The physics of the explosion and subsequent afterglow are hot topics of debate. Swift, together with ground based telescopes and other space observatories, are providing a wealth of data on gamma ray bursts and their afterglows. The Optical/Ultraviolet Telescope (UVOT) onboard Swift was designed and constructed at MSSL, and we host an operations team which plays a major role in the Swift observatory, analysing the gamma-ray burst data as it comes down from Swift.This project is for a PhD student to work alongside our operations team in studying gamma-ray bursts and to utilise the large body of UVOT data to further our understanding of the physics of these phenomenal explosions: how they are powered, how the relativistic blastwave deposits its energy into the surrounding medium, the environments in which gamma-ray bursts occur, what the progenitor stars could be, and what gamma-ray bursts tell us about the cosmic history of star and galaxy formation. The student will examine correlations between the gamma-ray and optical energetics, building on the correlation we recently found between the brightness of the afterglow and the speed with which it fades (Oates, Page et al. 2012, MNRAS 426, L26). The student will also experience real-time investigation and follow up of gamma-ray bursts, starting within the first few minutes of a burst being detected with Swift, with the opportunity to study in detail any exceptional bursts that go off when the student is on duty.The student will develop a front-line understanding of the physics of these explosions, and contribute to improving this understanding.