Mapping the cosmic web with neutral hydrogen during the era of the Square Kilometre Array

在平方公里阵列时代用中性氢绘制宇宙网

• 批准号: MR/V026437/1
• 负责人: Laura Wolz
• 金额: $ 139.72万
• 依托单位: University of Manchester
• 依托单位国家: 英国
• 项目类别: Fellowship
• 财政年份: 2022
• 资助国家: 英国
• 起止时间: 2022 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=MR%2FV026437%2F1
• 关键词: Mapping; cosmic; web; neutral; hydrogen

A key goal of cosmology is to understand the accelerated expansion of the Universe, believed to be driven by a force called Dark Energy. Mapping the distribution of galaxies throughout the Universe's lifetime can measure the expansion history and help us understand the nature of Dark Energy. Historically, cosmologists have successfully used the optical emission of stars located in galaxies to map the cosmic web over time. In the past decade, a new method called intensity mapping has emerged which uses the radio emission of gas (specifically the highly abundant Neutral Hydrogen gas) to trace the galaxy distribution. The Square Kilometre Array (SKA) - with headquarters at Jodrell Bank near Manchester - is an enormous radio telescope array to be built in the Australian and South African desserts, capable of higher sensitivities and spatial resolution than any existing radio instrument. The SKA is currently under construction, with first science verification data to come in around 2025, and major surveys to start after 2028. One of the major goals of the SKA is to observe the gas in distant and faint galaxies, which tells us about how galaxies formed and evolved with time. Intensity maps observed by the SKA will give new, independent insights into the evolution of our Universe. Intensity mapping is a unique probe, as it can be observed using the SKA as a single dish array, as well as in interferometric mode which gives much higher spatial resolution in the data. Both datasets are essential if we aim to acquire a complete understanding of how hydrogen traces dark matter and how gas and galaxies evolved with cosmic time. Only when we understand the hydrogen-galaxy relation can we reliably infer precision cosmology from the intensity maps.In this fellowship, I will lead the preparations for intensity mapping surveys with the SKA, as well its pathfinder arrays which are already observing the sky. Building on my exclusive experience with intensity maps from previous work on Green Bank Telescope data, I will establish a data analysis pipeline robust to foregrounds and instrumental systematics for the single dish observations. This pathfinder analysis will reliably constrain the large scale properties of hydrogen and pioneer expansion rate measurements with radio data. I will drive the efforts to detect the intensity mapping signal in interferometric data coming from the Australian SKA pathfinder, while also being part of the South African based MeerKAT team. This multi-project approach will help our understanding of the intricacies of the analysis due to instrumental and processing systematics. The higher resolution intensity maps will reveal information about the hydrogen contents within populations in galaxies and it's behaviour within clusters and groups of galaxies. I will also be developing new, inter-disciplinary approaches to explore the potential science of the intensity maps. This will include studying the empty space between galaxies, called voids, as they trace the cosmic evolution in a complementary way which is less biased through astrophysical processes. I will also introduce new imaging techniques based on compressive sensing, which are adaptable to scales of interest for each scientific interpretation, such as void analysis or galaxy clusters.My efforts on SKA pathfinder data as well as on preparing the future SKA data analysis pipeline will be crucial in order to reliably infer correct cosmology, as well as astrophysical galaxy evolution information from intensity mapping observations. I will put tight constraints on global hydrogen properties and cosmic expansion rates while developing novel techniques to search for unknown physics in these exciting new observations.

宇宙学的一个关键目标是了解宇宙的加速膨胀，据信是由一种称为暗能量的力量驱动的。绘制宇宙一生中星系的分布图可以测量膨胀历史，并帮助我们理解暗能量的本质。从历史上看，宇宙学家已经成功地利用位于星系中的恒星的光发射来绘制随时间变化的宇宙网。在过去的十年中，出现了一种称为强度映射的新方法，该方法使用气体（特别是高度丰富的中性氢气体）的无线电发射来追踪星系分布。平方公里阵列（SKA）-总部设在曼彻斯特附近的Jodrell Bank-是一个巨大的射电望远镜阵列，将在澳大利亚和南非沙漠中建造，能够比任何现有的无线电仪器具有更高的灵敏度和空间分辨率。SKA目前正在建设中，第一批科学验证数据将于2025年左右公布，主要调查将于2028年后开始。SKA的主要目标之一是观察遥远而微弱的星系中的气体，这告诉我们星系如何随着时间的推移形成和演化。SKA观测到的强度图将为我们的宇宙演化提供新的、独立的见解。强度映射是一种独特的探测器，因为它可以使用SKA作为单个碟形阵列进行观察，也可以在干涉测量模式下进行观察，从而在数据中提供更高的空间分辨率。这两个数据集是必不可少的，如果我们的目标是获得一个完整的理解氢如何跟踪暗物质和气体和星系如何演变与宇宙时间。只有当我们理解了氢-星系的关系，我们才能从强度图中可靠地推断出精确的宇宙学。在这个奖学金中，我将领导SKA强度图调查的准备工作，以及已经在观测天空的探路者阵列。基于我以前在绿色银行望远镜数据上工作的强度图方面的独家经验，我将建立一个数据分析管道，该管道对单碟观测的前景和仪器系统学具有鲁棒性。这一探索者分析将可靠地约束氢的大尺度性质，并利用无线电数据进行先驱膨胀率测量。我将努力在来自澳大利亚SKA探路者的干涉测量数据中检测强度映射信号，同时也是南非MeerKAT团队的一员。这种多项目的方法将有助于我们理解由于仪器和处理系统而导致的分析的复杂性。更高分辨率的强度图将揭示星系中人口中氢含量的信息，以及它在星系团和星系群中的行为。我还将开发新的跨学科方法来探索强度图的潜在科学。这将包括研究星系之间的空白空间，称为空洞，因为它们以互补的方式追踪宇宙演化，这种方式通过天体物理过程较少偏见。我还将介绍基于压缩传感的新成像技术，这些技术适用于每种科学解释的感兴趣的尺度，例如空洞分析或星系团。我在SKA探路者数据以及准备未来SKA数据分析管道方面的努力将是至关重要的，以便可靠地推断正确的宇宙学，以及从强度映射观测中获得天体物理星系演化信息。我将严格限制全球氢的性质和宇宙膨胀率，同时开发新的技术，在这些令人兴奋的新观测中寻找未知的物理。

项目成果

The foreground transfer function for HI intensity mapping signal reconstruction: MeerKLASS and precision cosmology applications

用于 HI 强度映射信号重建的前景传递函数：MeerKLASS 和精密宇宙学应用

• DOI: 10.48550/arxiv.2302.07034
• 发表时间: 2023
• 期刊: arXiv e-prints
• 作者: Cunnington Steven

Accurate Fourier-space statistics for line intensity mapping: Cartesian grid sampling without aliased power

用于线强度映射的精确傅里叶空间统计：无混叠功率的笛卡尔网格采样

• DOI: 10.1093/mnras/stae333
• 发表时间: 2024
• 期刊: Monthly Notices of the Royal Astronomical Society
• 影响因子: 4.8
• 作者: Cunnington S

H i intensity mapping with MeerKAT: Power spectrum detection in cross-correlation with WiggleZ galaxies

• DOI: 10.1093/mnras/stac3060
• 发表时间: 2022-06
• 期刊: Monthly Notices of the Royal Astronomical Society
• 影响因子: 4.8
• 作者: Steven Cunnington;Yichao Li;Mário G. Santos;Jingying Wang;I. Carucci;M. Irfan;A. Pourtsidou;M. Spinelli;L. Wolz;P. S. Soares;C. Blake;P. Bull;B. Engelbrecht;J. Fonseca;K. Grainge;Yin-Zhe Ma

A first detection of neutral hydrogen intensity mapping on Mpc scales at $z\approx 0.32$ and $z\approx 0.44$

首次检测到 $zapprox 0.32$ 和 $zapprox 0.44$ 处 Mpc 尺度上的中性氢强度图

• DOI: 10.48550/arxiv.2301.11943
• 发表时间: 2023
• 期刊: arXiv e-prints
• 作者: Paul Sourabh

Detecting the HI Power Spectrum in the Post-Reionization Universe with SKA-Low

使用 SKA-Low 检测再电离后宇宙中的高功率谱

• DOI: 10.48550/arxiv.2302.11504
• 发表时间: 2023
• 期刊: arXiv e-prints
• 作者: Chen Zhaoting