Gamma-ray bursts and their afterglows

伽马射线暴及其余辉

• 批准号: 2895128
• 金额: --
• 依托单位: Lancaster University
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2023
• 资助国家: 英国
• 起止时间: 2023 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2895128
• 关键词: Gamma; ray; bursts; their; afterglows

Gamma-ray bursts (GRBs) are brief, intense flashes of gamma-rays that are accompanied by longer lasting emission in the X-ray to radio wavelengths. The duration of the gamma-ray emission may be as short as a few milliseconds or may last for as long as a few hundred seconds, during which the GRB 'out-shines' all objects in the known universe. GRBs are divided, based on the duration of their gamma-ray emission, into two classes 'long' and 'short', which are associated, respectively, with the collapse of massive stars or the mergers of two compact objects (either two neutron stars or a neutron star and black hole). For his PhD, Sam will investigate the multi-wavelength afterglows of GRBs and what they can tell us about the environments GRBs explode in to, their central engines and the structure of their jets. He will initially begin by focusing on a correlation found in the optical, X-ray and GeV wavelength light curves. This correlation connects the early intrinsic brightness of GRB afterglows in these wavelengths with their average rate of decay, such that the brightest afterglows decay more quickly than the fainter ones. This correlation may be a result of an intrinsic property which regulates the energy release, with the energy of brighter afterglows being released more quickly than the fainter ones. Alternatively, this correlation may be due to a geometric effect caused by viewing angle, with the fainter slower decaying afterglows viewed more off-axis compared to their brighter and faster decaying counterparts. Sam will begin this investigation by determining whether the correlation exists also in the radio light curves.Sam will primarily work on GRBs observed by the NASA Swift satellite, the UK has key involvement in two of the three instruments onboard - the Ultra-violet and optical telescope and the X-ray telescope. Sam will be directly involved in Swift as a member of the UVOT team. He will participate in real time observation and follow-up of GRBs with UVOT and ESO telescopes through membership of the Swift and STARGATE teams. He will also participate in the search for the electromagnetic counterpart of gravitational waves through membership of ENGRAVE collaboration.

伽玛射线暴（GRBs）是一种短暂的、强烈的伽玛射线闪光，伴随着较长时间的x射线到无线电波长的发射。伽马射线发射的持续时间可能短至几毫秒，也可能长达几百秒，在此期间，GRB比已知宇宙中的所有物体都“闪耀”。根据伽马射线发射的持续时间，grb被分为“长”和“短”两类，它们分别与大质量恒星的坍缩或两个致密物体（两颗中子星或一颗中子星和黑洞）的合并有关。为了攻读博士学位，山姆将研究伽马射线暴的多波长余辉，以及它们能告诉我们的关于伽马射线暴爆炸的环境、它们的中央引擎和喷流结构的信息。他将首先关注在光学、x射线和GeV波长光曲线中发现的相关性。这种相关性将这些波长的伽马射线暴余辉的早期固有亮度与它们的平均衰减速率联系起来，因此最亮的余辉比较暗的余辉衰减得更快。这种相关性可能是调节能量释放的内在特性的结果，较亮的余辉比较暗的余辉释放的能量更快。或者，这种相关性可能是由于观察角度引起的几何效应，与更亮、更快的余辉相比，更暗淡、更慢的衰减余辉更偏离轴。Sam将通过确定这种相关性是否也存在于射电光曲线中来开始这项研究。Sam将主要研究由NASA Swift卫星观测到的grb，英国在机载的三种仪器中有两种——紫外光学望远镜和x射线望远镜——发挥了关键作用。Sam将作为UVOT团队的一员直接参与Swift。他将通过Swift和STARGATE团队的成员，参与UVOT和ESO望远镜对grb的实时观测和跟踪。他还将通过ENGRAVE合作组织的成员身份参与寻找引力波的电磁对应物。