Observational cosmology with multi-wavelength surveys

多波长观测宇宙学

• 批准号: ST/P004474/2
• 负责人: David Alonso
• 金额: $ 48.86万
• 依托单位: University of Oxford
• 依托单位国家: 英国
• 项目类别: Fellowship
• 财政年份: 2019
• 资助国家: 英国
• 起止时间: 2019 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=ST%2FP004474%2F2
• 关键词: Observational; cosmology; multi; wavelength; surveys

Cosmology studies the large-scale properties and evolution of the Universe. As such, cosmology is arguably one of the most complete branches of physics in that it must be able to describe the large-scale distribution and motion of matter, governed primarily by the gravitational forces, but also the intricate interactions between subatomic particles that dictated the rules during and after the Big Bang, as well as the violent physical processes that take place in galaxies and clusters of galaxies. However, the most characteristic feature of cosmology that separates it from other branches of physics, is the impossibility to replicate experiments. We only have one set of data: the Universe, and we cannot repeat it. This originally put cosmology in an awkward position, where due to the lack of experimental data, progress was mainly driven by theoretical work based on fundamental premises. Astonishingly, as astronomical observations improved, many of these theoretical predictions were actually found to be valid, and the last couple of decades have seen cosmology grow into a fully fleshed science driven by experimental observations.Since there is only one Universe to observe, the cosmologist's quest is to observe as much of it as possible: to map out the distribution of matter and energy in the entire observable Universe. The aim of this endeavour is not merely cartographic. Due to the finiteness of the speed of light, we see distant structures the way they were at the time the photons we observe were emitted. This way the cosmologist is also able to travel in time, and therefore the cosmologist's ideal map describes not only the current state of the Universe, but also its evolution since the moment of the Big Bang. So far we have only been able to collect separate pieces of this map, covering the early stages in the evolution of the Universe from measurements of the cosmic microwave background (CMB) emitted shortly after the Big Bang, as well as the late-time steps in this evolution, in terms of observations of the distribution of galaxies around us. However, in the next decade, large steps will be taken towards the completion of the cosmologist's ideal map: at least half of the observable sky will be jointly mapped by different experiments in a wide range of the electromagnetic spectrum, and these observations will cover far larger volumes than have been accessible so far.However, the cosmological information is encoded into these datasets in the form of an absorbing puzzle: different experiments cover different ranges of radial and angular scales, as well as different energy regimes, and certain sections of the data end up being dominated by non-cosmological sources and instrumental effects. The beautiful cosmologist's map must therefore be carefully disentangled from the raw experimental data, lest it be inevitably contaminated. This project focuses on identifying the regions and combinations of these datasets that are valuable to reconstruct this map, and that contain the most relevant cosmological information, making use of state-of-the-art statistical and computational tools. As an example, one of the main objectives of this project is the detection of primordial gravitational waves, the ripples in space-time originated during the Big-Bang, which could teach us a lot about the physical conditions in the early Universe. These waves leave an imprint in the polarisation of the CMB with an amplitude significantly smaller than the emission of our own galaxy, and therefore the latter must be carefully removed from the data before the former can be studied.With cosmology soon entering the era of "big data", as most other branches of science are currently doing, many of the algorithms and methods developed for this project will be useful for a wide range of disciplines, from atmospheric physics to the social sciences, and the computing needs of cosmological studies will also act as a driver for technological development.

宇宙学研究宇宙的大尺度特性和演化。因此，宇宙学可以说是物理学最完整的分支之一，因为它必须能够描述主要受引力控制的物质的大规模分布和运动，而且还能够描述亚原子粒子之间复杂的相互作用，这些相互作用决定了宇宙的运动。大爆炸期间和之后的规则，以及星系和星系团中发生的剧烈物理过程。然而，宇宙学与其他物理学分支的最大区别在于它无法重复实验。我们只有一组数据：宇宙，而且我们无法重复它。这原本让宇宙学处于一个尴尬的境地，由于缺乏实验数据，进展主要由基于基本前提的理论工作推动。令人惊讶的是，随着天文观测的改进，许多理论预测实际上被发现是有效的，并且在过去的几十年里，宇宙学已经发展成为一门由实验观测驱动的完全充实的科学。由于只有一个宇宙可供观测，宇宙学家的追求的是尽可能多地观察它：绘制出整个可观察宇宙中物质和能量的分布。这项努力的目的不仅仅是制图。由于光速的有限性，我们看到的远处结构与我们观察到的光子发射时的样子一样。通过这种方式，宇宙学家也能够进行时间旅行，因此宇宙学家的理想地图不仅描述了宇宙的当前状态，还描述了自大爆炸那一刻以来的演化。到目前为止，我们只能收集这张地图的各个部分，通过对大爆炸后不久发出的宇宙微波背景（CMB）的测量来覆盖宇宙演化的早期阶段，以及后期的步骤在这个演化过程中，根据对我们周围星系分布的观测。然而，在接下来的十年里，宇宙学家的理想地图将朝着完成迈出一大步：至少一半的可观测天空将通过不同的实验在广泛的电磁频谱中联合绘制，这些观测将覆盖很远的地方。然而，宇宙学信息以引人入胜的谜题形式编码到这些数据集中：不同的实验涵盖不同范围的径向和角度尺度，以及不同的能量状态，以及宇宙的某些部分。数据最终被非宇宙学来源和工具效应所主导。因此，美丽的宇宙学家地图必须小心地从原始实验数据中分离出来，以免不可避免地受到污染。该项目的重点是利用最先进的统计和计算工具，识别这些数据集的区域和组合，这些区域和组合对重建该地图有价值，并且包含最相关的宇宙学信息。例如，该项目的主要目标之一是探测原始引力波，即起源于大爆炸期间的时空涟漪，这可以让我们了解很多有关早期宇宙物理条件的信息。这些波在 CMB 的偏振中留下了印记，其振幅明显小于我们自己星系的发射，因此在研究前者之前必须小心地从数据中删除后者。随着宇宙学很快进入“时代”正如大多数其他科学分支目前正在做的那样，为该项目开发的许多算法和方法将适用于从大气物理学到社会科学的广泛学科，并且宇宙学研究的计算需求将也起到了技术驱动的作用 发展。

项目成果

Cross-correlating radio continuum surveys and CMB lensing: constraining redshift distributions, galaxy bias, and cosmology

射电连续谱巡天和 CMB 透镜的互相关：约束红移分布、星系偏差和宇宙学

• DOI: http://dx.10.1093/mnras/stab046
• 发表时间: 2021
• 期刊: Monthly Notices of the Royal Astronomical Society
• 影响因子: 4.8
• 作者: Alonso D

Noise angular power spectrum of gravitational wave background experiments

引力波背景实验的噪声角功率谱

• DOI: http://dx.10.1103/physrevd.101.124048
• 发表时间: 2020
• 期刊: Physical Review D
• 影响因子: 5
• 作者: Alonso D

Linear anisotropies in dispersion-measure-based cosmological observables

基于色散测量的宇宙学可观测量中的线性各向异性

• DOI: http://dx.10.1103/physrevd.103.123544
• 发表时间: 2021
• 期刊: Physical Review D
• 影响因子: 5
• 作者: Alonso D

The Simons Observatory: gain, bandpass and polarization-angle calibration requirements for B-mode searches

西蒙斯天文台：B 模式搜索的增益、带通和偏振角校准要求

• DOI: http://dx.10.1088/1475-7516/2021/05/032
• 发表时间: 2021
• 期刊: Journal of Cosmology and Astroparticle Physics
• 影响因子: 6.4
• 作者: Abitbol M

The Atacama Cosmology Telescope: DR4 maps and cosmological parameters

阿塔卡马宇宙学望远镜：DR4 地图和宇宙学参数

• DOI: 10.1088/1475-7516/2020/12/047
• 发表时间: 2020-07-14
• 期刊: Journal of Cosmology and Astroparticle Physics
• 影响因子: 6.4
• 作者: S. Aiola;E. Calabrese;L. Maurin;S. Naess;B. Schmitt;M. Abitbol;G. Addison;P. Ade;D. Alonso;M. Amiri;S. Amodeo;Elio Angile;J. Austermann;T. Baildon;N. Battaglia;J. Beall;R. Bean;D. Becker;J. Bond;S. M. Bruno;Victoria Calafut;L. Campusano;Felipe Carrero;G. Chesmore;Hsiao;Steve K. Choi;S. Clark;N. Cothard;D. Crichton;K. Crowley;O. Darwish;R. Datta;E. Denison;M. Devlin;C. Duell;S. Duff;A. Duivenvoorden;J. Dunkley;R. Dunner;T. Essinger;M. Fankhanel;S. Ferraro;A. Fox;Brittany Fuzia;P. Gallardo;V. Gluscevic;J. Golec;E. Grace;M. Gralla;Yilun Guan;K. Hall;M. Halpern;Dongwon Han;P. Hargrave;M. Hasselfield;J. M. Helton;S. Henderson;B. Hensley;J. Hill;G. Hilton;M. Hilton;A. Hincks;R. Hlovzek;S. Ho;J. Hubmayr;K. Huffenberger;J. Hughes;L. Infante;K. Irwin;Rebecca Jackson;J. Klein;K. Knowles;B. Koopman;A. Kosowsky;Vincent Lakey;Dale Li;Yaqiong Li;Zack Li;M. Lokken;T. Louis;M. Lungu;Am;a Macinnis;a;M. Madhavacheril;Felipe Maldonado;M. Mallaby;D. Marsden;J. McMahon;F. Menanteau;K. Moodley;Tim Morton;T. Namikawa;F. Nati;L. Newburgh;J. Nibarger;A. Nicola;M. Niemack;M. Nolta;John Orlowski;L. Page;C. Pappas;B. Partridge;P. Phakathi;H. Prince;R. Puddu;F. J. Qu;J. Rivera;N. Robertson;F. Rojas;M. Salatino;E. Schaan;A. Schillaci;N. Sehgal;B. Sherwin;C. Sierra;J. Sievers;C. Sifón;Precious Sikhosana;S. Simon;D. Spergel;S. Staggs;J. Stevens;E. Storer;D. Sunder;E. Switzer;B. Thorne;R. Thornton;H. Trac;J. Treu;C. Tucker;L. Vale;A. V. Engelen;J. Lanen;E. Vavagiakis;K. Wagoner;Yuhan Wang;J. Ward;Edward J. Wollack;Zhilei Xu;Fern;o Zago;o;N. Zhu
• 通讯作者: N. Zhu