Line intensity mapping at mm/sub-mm wavelengths: developing a new probe of cosmology

线强度映射（LIM）是一种很有前途的观测技术，在宇宙学和天体物理学的许多领域都有应用。空间分布和测量的红移特定发射线作为物质分布底层的示踪剂，使我们能够在整个宇宙历史中建立大规模结构的3D地图。在毫米/亚毫米波长范围内存在广泛的光谱发射线，提供多个独立的示踪剂，使我们能够跨越红移范围探测到再电离时代的结构。卡迪夫的天文仪器小组（AIG）在长波仪器的发展方面有着悠久的声誉，我们现在在一些关键实验中发挥着主导作用，包括西蒙天文台（SO）和南极望远镜（SPT）。该项目提供了一个开发新的实验方法的机会，这些方法需要实现毫米波长的LIM，以及对SPT拍摄的新的和最近的天空数据集进行分析。该项目的实验方面将侧重于开发新型超导片上毫米波光谱仪，该光谱仪将为下一代LIM调查进行优化。其体积小、可扩展性强、灵敏度高等特点，都能很好地满足未来毫米波LIM实验的需要。AIG在超导探测器技术和毫米波仪器的开发方面处于世界领先地位，该项目利用了AIG广泛的设施和能力，包括；低温低温测试设备，毫米/亚毫米准光学元件，以及一个新的最先进的纳米制造中心，通过AIG在化合物半导体研究所的作用。卡迪夫大学参与了SPT夏季线强度测绘仪（SPT- slim）的设计、建造和部署，这是一个探路者实验，致力于证明片上光谱仪技术对LIM的适用性。计划于2023年底部署，SPT-SLIM将在南部夏季进行观测，预计将提供新的丰富数据集。在整个博士项目期间，成功的候选人将有机会在分析和数据简化管道的开发和测试中承担重要角色，这是将毫米波LIM建立为新的宇宙学观测的关键一步。

Line Intensity Mapping (LIM) is a promising observational technique with applications spanning many areas of cosmology and astrophysics. The spatial distribution and measured redshift specific emission lines serve as a tracer of the underlying of the distribution of matter that allows us to build 3D maps of large-scale structure throughout the history of the Universe. There exists a wide range of spectral emission lines that fall within the mm/sub-mm wavelength range, providing multiple independent tracers that allow us probe structure across a redshift range out to the epoch of reionisation. The Astronomy Instrumentation Group (AIG) at Cardiff has a long-standing reputation in the development of long-wavelength instrumentation and we are now playing leading roles in a number of key experiments, including the Simon's Observatory (SO) and the South Pole Telescope (SPT). This project provides an opportunity to develop new experimental approaches that are needed to realise LIM at mm wavelengths, as well as lead analysis of new and recent on-sky datasets taken with the SPT. The experimental aspect of this project will focus on the development of a new class of superconducting on-chip mm-wave spectrometers that will be optimised for the next generation of LIM surveys. The small size, natural scalability, and intrinsic detector sensitivity are all well matched to the needs of future mm-wave LIM experiments. The AIG is a world leader in the development of superconducting detector technologies and mm-wave instrumentation, and this project leverages the broad range of AIG facilities and capabilities including; low-temperature cryogenic test equipment, mm/sub-mm quasi-optical components, and a new state-of-the-art nanofabrication centre through the AIG's role within the Institute for Compound Semiconductors.Cardiff is involved in the design, construction, and deployment of the SPT Summertime Line Intensity Mapper (SPT-SLIM), a pathfinder experiment dedicated to demonstrating the suitability of on-chip spectrometer technology for LIM. Scheduled to deploy in late 2023, SPT-SLIM will observe during the austral summer and is expected to provide a new and rich dataset. Throughout the duration of this Ph.D. project, the successful candidate will have opportunities to undertake important roles in the development and testing of the analysis and data reduction pipeline, a critical step toward establishing mm-wave LIM as a new cosmological observable.