Investigation into the diversity of relativistic explosions in the universe

伽马射线暴（GRB）的特征是短暂而强烈的伽马射线喷射发射，使其成为宇宙中最具能量的事件之一。它们的持续时间从几毫秒到一百多秒，通常会伴随着余辉--以从X射线到无线电波长的电磁辐射形式延伸的辐射。余辉不仅与伽玛暴有关，也可以在其他高能爆炸中观察到，或者理论上说，如果伽玛暴没有发生或无法观察到，余辉可能会自己出现。研究伽玛暴及其余辉可以提供有关喷流形成和相对论爆炸如何随时间演变的有价值的见解，也可以提供有关它们的祖先或由此产生的重元素核合成的信息。然而，通常难以测量的是不同类型的相对论事件有多常见，以及它们的真实发生率是多少。该项目首先将集中于在多个波长中模拟单个余辉事件。然而，总的目标是调查余辉的样本，并设置约束条件，如喷流开口角，洛伦兹因子或祖星星金属丰度如何影响这些事件的生产和观测率，以及不同的喷流现象的比率。通过对利物浦望远镜（LT）、ZTF、Lick等观测设备的观测数据进行分析，并与数值模拟进行比较。此外，如果通过引力波观测发现中子星星合并，则参与寻找其光学对应物并进行分析。这将有助于限制紧凑物体合并的速度，并提供关于相对论爆炸演变的更多数据。

Gamma-ray bursts (GRBs) are characterized by brief and intense jetted emission of gamma-ray radiation, making them some of the most energetic events in the universe. They last from milliseconds up to over a hundred seconds and are typically followed by afterglows - extended emission in the form of EM radiation from X-ray to radio wavelengths. Afterglows are not tied only to GRBs, but are observed with other energetic explosions as well, or might, theoretically, appear on their own, if the GRB emission did not take place or was impossible to observe.Studying GRBs and their afterglows can provide valuable insight into jet formation and how relativistic explosions evolve in time, as well as provide information on their progenitors, or the resulting nucleosynthesis of heavy elements. However, what is often difficult to measure is how common the different types of relativistic events are, and what are their true occurrence rates.The project at first will be focused on modelling a single afterglow event in multiple wavelengths. However, the overall aim is to investigate a sample of afterglows and set constraints on how variables such as jet opening angle, Lorentz factor or progenitor star metallicity influence the production and observation rate of those events, as well as the rates of different jet phenomena. This will be done through the analysis of observational data from facilities like the Liverpool Telescope (LT), Zwicky Transient Facility (ZTF), or Lick, as well as comparison to numerical simulations.Additionally, if a neutron star merger is detected from gravitational wave observations, then I will take part in searching for its optical counterpart and its analysis. This would help constrain the rate of compact object mergers and provide additional data on the evolution of relativistic explosions.