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Exploring the Universe with radio and optical galaxy surveys

通过射电和光学星系巡天探索宇宙

基本信息

批准号：
MR/S016066/2
负责人：
Alkistis Pourtsidou
金额：
$ 63.04万
依托单位：
University of Edinburgh
依托单位国家：
英国
项目类别：
Fellowship
财政年份：
2021
资助国家：
英国
起止时间：
2021 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=MR%2FS016066%2F2
关键词：
Exploring Universe radio optical galaxy

项目摘要

During the last two decades we have entered a "golden era" of cosmology. Using satellites and ground based telescopes we have gathered high quality data from the very early Universe, essentially from light emitted right after the Big Bang explosion, as well as from the late Universe, through the light emitted from stars and galaxies.However, a big part of our Universe's history and volume remains unexplored. A way to attack this challenge is by observing the light emitted from the neutral hydrogen (HI) that filled the Universe for a long time after the Big Bang and before the first galaxies were formed. After that time HI resides within galaxies, so we can also use it as a novel way to study the late Universe. This is my main area of research; it is exciting because it opens a new observational window into the Universe and can push the boundaries of our understanding of astrophysics and cosmology.In the next few years, HI surveys of exquisite sensitivity will be performed using radio telescopes, and part of the proposed research is working on new techniques in order to maximise their science output. I have pioneered a new observational method that does not require the -difficult and expensive- detection of individual galaxies but maps the entire HI flux coming from many galaxies together in large 3D pixels (across the sky and along time). I aim to use this technique to provide a 3D map of the Universe using HI intensity mapping data from the MeerKAT and SKA arrays. MeerKAT is a radio telescope located in Karoo, South Africa, and it is a pathfinder for the Square Kilometre Array (SKA), which is going to be the largest radio telescope in the world.My main goal is to build a complete pipeline for the cosmological analysis of the HI intensity mapping signal from instruments like MeerKAT and the SKA. This pipeline will also account for the possibility of powerful synergies between HI and traditional optical galaxy surveys, by including cross-correlations data analysis tools. This is useful in order to obtain measurements that are free of systematic contaminations that often plague individual surveys (but drop out when combining them), and therefore more robust. I aim to perform the first ever measurements of HI and cosmological parameters in the radio wavelength using the intensity mapping technique, exploit multi-wavelength synergies, and revolutionarise our understanding of galaxy evolution and dark energy. I am also working on two of the largest and best optical galaxy surveys of the next decade, the Euclid satellite mission and the ground-based Large Synoptic Survey telescope, whose main goals are to measure dark energy and understand the initial conditions of the Universe. In Euclid, I am working on various projects including building the software tools that are going to be used for the analysis of the data as soon as they become available. I am also working on the very challenging task of modelling the way galaxies cluster on small scales, in order to extract useful information for cosmology. I am also using tailored simulations to assess how well Euclid will measure the largest cosmological scales in order to characterise the initial conditions of the Universe. In both Euclid and LSST, I am working on synergies with radio experiments. My goal is to find innovative ways to optimally combine optical and radio surveys, in order to maximise their joint scientific output. Another exciting part of working with these surveys is the huge amount of data that are going to be available. For example, the Phase 1 of the SKA is expected to generate 300 petabytes of data products every year. My research includes developing modernised and innovative data processing and analysis pipelines, which is required for the success of these amazing surveys.

在过去的二十年里，我们进入了宇宙学的“黄金时代”。利用卫星和地面望远镜，我们已经收集了来自早期宇宙的高质量数据，主要是来自大爆炸后发出的光，以及来自晚期宇宙的恒星和星系发出的光。然而，我们宇宙的历史和体积的很大一部分仍未被探索。应对这一挑战的一种方法是观察大爆炸后和第一个星系形成之前很长一段时间充满宇宙的中性氢（HI）发出的光。在那之后，HI驻留在星系中，所以我们也可以用它作为研究晚期宇宙的一种新方法。这是我的主要研究领域;它是令人兴奋的，因为它打开了一个新的观察宇宙的窗口，可以推动我们对天体物理学和宇宙学的理解的边界。在未来几年，高灵敏度的HI调查将使用射电望远镜进行，部分拟议的研究正在研究新技术，以最大限度地提高其科学产出。我开创了一种新的观测方法，它不需要对单个星系进行困难而昂贵的探测，而是将来自许多星系的整个HI通量以大的3D像素绘制在一起（跨越天空和沿着时间）。我的目标是使用这种技术来提供一个3D的宇宙地图使用HI强度映射数据从MeerKAT和SKA阵列。MeerKAT是位于南非卡鲁的射电望远镜，它是平方公里阵列（SKA）的探路者，SKA将成为世界上最大的射电望远镜。我的主要目标是建立一个完整的管道，用于对来自MeerKAT和SKA等仪器的HI强度映射信号进行宇宙学分析。这一管道还将通过包括互相关数据分析工具来说明HI和传统光学星系调查之间强大协同作用的可能性。这是有用的，以获得测量是免费的系统污染，往往困扰个别调查（但退出时，合并它们），因此更强大。我的目标是执行有史以来第一次测量的HI和宇宙学参数的无线电波长使用的强度映射技术，利用多波长的协同作用，并彻底改变我们的星系演化和暗能量的理解。我还在进行下一个十年中最大和最好的两个光学星系调查，欧几里得卫星使命和地面大型综合调查望远镜，其主要目标是测量暗能量和了解宇宙的初始条件。在欧几里得，我正在从事各种项目，包括建立软件工具，将用于分析的数据，一旦他们成为可用的。我还在从事一项非常具有挑战性的任务，即模拟星系在小尺度上聚集的方式，以便为宇宙学提取有用的信息。我还使用定制的模拟来评估欧几里得如何测量最大的宇宙尺度，以确定宇宙的初始条件。在欧几里得和LSST中，我正在研究与无线电实验的协同作用。我的目标是找到创新的方法来最佳地结合联合收割机光学和无线电调查，以最大限度地提高他们的联合科学产出。使用这些调查的另一个令人兴奋的部分是将提供大量的数据。例如，SKA的第一阶段预计每年将产生300 PB的数据产品。我的研究包括开发现代化和创新的数据处理和分析管道，这是这些惊人的调查成功所必需的。