Development of Sub-Millimetre Heterodyne Array & Probing the Interstellar Medium of Nearby Galaxies with JWST and ALMA

这种哲学博士。该项目包括两个互补的科学课题：一个是开发亚毫米量子探测器，另一个是利用JWST和ALMA的中红外（MIR）数据的观测项目。恒星形成区域的物理和化学条件可以通过观察毫米和亚毫米波长来确定，在那里可以找到大量的原子、离子和分子谱线。近年来，对这些谱线的光谱和干涉观测改进了我们对附近和遥远星系的气体动力学和运动学的认识，并使第一次直接探测黑洞图像成为可能。由于超导体-绝缘体-超导体（SIS）外差接收器的非凡特性，这些观测结果才有可能实现。SIS混频器通常用于天文台，如北方扩展毫米阵列（NOEMA），阿塔卡马大型毫米/亚毫米阵列（ALMA）和赫歇尔空间天文台，仅举几例，可以以高光谱和空间分辨率对微弱物体进行大量观测。然而，在不久的将来利用SIS接收器进行地面或天基天文观测有一个主要的限制。传统的高光谱分辨率观测需要过多的望远镜时间。这阻碍了重要的科学计划，特别是在补充大面积连续映射数据时，例如，赫歇尔热测量阵列缺乏动态和运动学信息，或者需要大面积高空间和光谱分辨率的科学。提高制图速度需要增加探测器的数量和/或提高灵敏度。然而，大多数现有的亚毫米仪器都达不到最终的量子极限，这对成像高z星系和黑洞至关重要。此外，这些仪器通常具有有限数量的空间像素，使得绘制银河系平面和附近星系内的大型结构成为一项艰巨的挑战。现在需要新一代的超灵敏宽视场基础设施，例如，计划中的地基（例如，AtLAST， LST）和天基（例如，NASA Probe）望远镜，预计将配备大像素外差阵列（~103像素），并且必须在建造时保持非凡的单个像素灵敏度。只有当所需的技术发展到高TRL时，包括在现有望远镜上进行小规模的演示，才有可能满怀信心地计划建造大型仪器。这种哲学博士。因此，该项目旨在通过开发小像素亚毫米外差阵列来解决这些挑战，涉及每个阶段的先进技术，使其模块化和可阵列化，着眼于未来部署千像素接收器。该项目的目标是通过开发双偏振亚毫米外差演示器来演示该技术，该演示器将保留完整的天文信号强度并保留偏振信息。在科学观测部分，该学生将利用詹姆斯·韦伯太空望远镜（JWST）中红外光谱仪（MIRI）和阿塔卡马大型毫米阵列（ALMA）的数据，重点研究附近星系样本的星际介质。JWST的出现为我们提供了前所未有的灵敏度和空间分辨率，使我们能够在近星系和远星系中以空间分辨率的方式研究ISM的特性。该项目将专注于附近星系的样本，并将首次检查基于中红外（MIR）离子线的元素丰度，这些元素丰度不受温度依赖性的影响，因此将提供可靠的金属丰度梯度估计。此外，学生将比较分子气体的分布（通常用于追踪原料）

This D.Phil. programme is comprising two complementary science topics: A focus on the development of the sub-millimetre quantum detector, and an observation project utilising mid-infrared (MIR) data from JWST and ALMA.The physical and chemical conditions in star-forming regions can be determined by observing at millimetre and sub-millimetre wavelengths, where a host of atomic, ionic and molecular lines can be found. In recent years, spectroscopic and interferometric observations of these lines have refined our knowledge of the gas dynamics and kinematics of nearby and distant galaxies, as well as enabling the first direct detection of black hole images. These observations have only been possible because of the extraordinary characteristics of near quantum-noise-limited Superconductor-Insulator-Superconductor (SIS) heterodyne receivers. SIS mixers are used routinely on observatories such as the Northern Extended Millimetre Array (NOEMA), the Atacama Large Millimetre/sub-millimetre Array (ALMA), and the Herschel space observatory, to name a few, enabling numerous observations of faint objects with high spectral and spatial resolution. However, there is a major limitation in utilising SIS receivers for near future astronomical observation, either ground-based or space-borne.Traditional high spectral resolution observations demand excessive telescope time. This hampers important scientific programs, especially when complementing large-area continuum mapping data done by e.g., bolometric arrays on Herschel which lack of dynamic and kinematic information, or science that require large area high spatial and spectral resolution. Improving mapping speed entails increasing the number of detectors and/or enhancing sensitivity. However, most existing sub-mm instruments fall short of reaching the ultimate quantum limit, crucial for imaging high-z galaxies and black holes. Additionally, these instruments often possess a limited number of spatial pixels, making mapping large structure within the Galactic plane and nearby galaxies a formidable challenge.A new generation of ultra-sensitive wide-field infrastructure is now required e.g., the planned ground-based (e.g., AtLAST, LST) and space-based (e.g., NASA Probe) telescopes, that are expected to be equipped with large pixel count heterodyne arrays (~103 pixels) and must be built whilst retaining extraordinary levels of individual-pixel sensitivity. It is only possible to plan the construction of large instruments with confidence, once the needed technology has been developed to high TRL, including smaller-scale demonstration on existing telescopes. This D.Phil. project therefore aim to address these challenges by developing a small-pixel count sub-millimetre heterodyne array, involving advancing techniques at every stage, making them modular and array-able, with an eye towards enabling the future deployment of kilo-pixel receivers. The project targets to demonstrate the technologies by developing a dual-polarisation sub-millimetre heterodyne demonstrator, which would retain the full astronomical signal strength and preserve the polarisation information. For the scientific observation part, the student will focus on an investigation of the Interstellar Medium of a sample of nearby galaxies using data from the James Webb Space Telescope (JWST) Mid-Infrared Spectrometer (MIRI) and the Atacama Large Millimetre Array (ALMA). The advent of JWST has provided us with unprecedented sensitivity and spatial resolution to enable studies of the properties of the ISM in a spatially resolved manner in galaxies near and far. The project will focus on a sample of nearby galaxies and will examine, for the first time, element abundances based on mid-infrared (MIR) ionic lines which are unaffected by temperature dependencies and therefore will deliver robust estimates of metallicity gradients. Furthermore, the student will compare the distribution of molecular gas (often used to trace the raw ma