Investigation into the diversity of relativistic explosions in the universe

伽马射线暴（GRBs）的特点是短暂而强烈的伽马射线喷射发射，使它们成为宇宙中能量最高的事件之一。它们的持续时间从几毫秒到一百多秒不等，通常伴随着余辉——从x射线到无线电波长的EM辐射形式的延伸发射。余辉不仅与伽马射线暴有关，也可以与其他高能爆炸一起观测到，或者理论上，如果伽马射线暴没有发生或不可能观测到，余辉也可能单独出现。研究伽马射线暴及其余辉可以为了解喷流的形成以及相对论性爆炸如何随时间演化提供有价值的见解，并提供有关其前身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性事件有多普遍，以及它们的真实发生率是多少。该项目首先将集中于模拟多个波长的单一余辉事件。然而，总体目标是研究余辉的样本，并设置诸如射流开口角度、洛伦兹因子或祖星金属丰度等变量如何影响这些事件的产生和观测速率，以及不同射流现象的速率的限制。这将通过分析来自利物浦望远镜（LT）、兹威基瞬变设施（ZTF）或利克等设施的观测数据，以及与数值模拟的比较来完成。此外，如果从引力波观测中发现中子星合并，那么我将参与寻找其光学对应物并进行分析。这将有助于限制致密天体合并的速度，并为相对论性爆炸的演化提供额外的数据。

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.