RUI: Collaborative Research: Beyond the Bulk Flow: Developing More Powerful Analysis Methods to Test Consistency of Large-scale Flows with the Standard Cosmological Model

RUI：协作研究：超越整体流动：开发更强大的分析方法来测试大规模流动与标准宇宙学模型的一致性

• 批准号: 1907365
• 负责人: Richard Watkins
• 金额: $ 18.46万
• 依托单位: Willamette University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-09-01 至 2023-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1907365&HistoricalAwards=false
• 关键词: RUI; Collaborative; Research; Beyond; Bulk

It has long been observed that light from distant galaxies is received on earth at a different wavelength than that at which it was emitted. This shift in wavelength, often called redshift, is due to two distinct effects, the Doppler shift that arises from the motion of galaxies relative to the Milky Way and the stretching of light that is caused by its traveling through expanding space. These effects can be separated only if independent measurements of galaxy distances can be obtained. However, as the number and accuracy of distance measurements have improved, it appears that the shift due to expansion is significantly larger than expectations based on much larger scale observations. Furthermore, studies of the motions of galaxies have revealed large-scale flows that are also larger than expected. The goal of this project is to develop new ways of analyzing available redshift and distance measurements in order to better understand the sources of the conflict between the data and the model. In particular, the investigators seek to determine if the disagreements are due to undiscovered problems with the measurements or if they are indeed pointing the way toward a previously unknown aspect of our Universe. The data analysis techniques developed here will have broad application and may help advance other fields, particularly those that rely on noisy data. This project will strengthen the US science workforce by providing intensive research experiences and training to undergraduate students in data analysis and statistics, areas of high demand and of strategic importance to the nation. In addition, a programming course related to the proposed research will be developed and taught to secondary school students at Willamette Academy, a college access program for underrepresented students associated with Willamette University.As the number and accuracy of galaxy distance measurements have improved, they have become increasingly important as a cosmological probe of the local Universe. However, it has become apparent that this data is in conflict with observations of the microwave background radiation and the Standard Cosmological Model. The goal for this proposal is to develop and apply new statistical methods to analyze collections of redshift and distance measurements, also known as peculiar velocity catalogs, with the following goals: (1) to put stronger constraints on cosmological parameters; (2) to better understand the dynamics of the large-scale structure and the expansion rate of the Universe; and (3) to test for systematics in this important type of cosmological data. The proposed research will clarify whether redshift and distance measurements are actually in conflict with the Standard Model, and if so, the severity and source of the disagreement. Searching for the causes of the discrepancies in both the expansion rate determination and the observed motion of the local volume is important for gaining a more complete understanding of the Universe. A resolution of these conflicts may lead to new physics or to a better understanding of some yet-to-be-determined systematics in this important cosmological probe.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

长期以来，人们一直观察到，地球接收到的来自遥远星系的光的波长与它发射时的波长不同。 这种波长的变化，通常被称为红移，是由于两种不同的效应，多普勒频移是由星系相对于银河系的运动引起的，而光的拉伸是由它穿过膨胀的空间引起的。 这些效应只有在独立测量星系距离的情况下才能分开。 然而，随着距离测量的数量和准确性的提高，由于膨胀而产生的偏移似乎比基于更大规模观测的预期要大得多。 此外，对星系运动的研究揭示了比预期更大的大规模流动。该项目的目标是开发分析现有红移和距离测量的新方法，以便更好地理解数据和模型之间冲突的来源。特别是，研究人员试图确定这些分歧是否是由于测量中未发现的问题，或者它们是否确实指向我们宇宙中以前未知的方面。 这里开发的数据分析技术将有广泛的应用，并可能有助于推进其他领域，特别是那些依赖于噪声数据。该项目将通过为数据分析和统计方面的本科生提供密集的研究经验和培训来加强美国的科学劳动力，这些领域对国家具有高需求和战略重要性。此外，还将为威拉米特学院的中学生开发和教授与拟议研究有关的编程课程，威拉米特学院是威拉米特大学为代表性不足的学生提供的大学入学计划。随着星系距离测量的数量和准确性的提高，它们作为对本地宇宙的宇宙学探测变得越来越重要。 然而，很明显，这些数据与微波背景辐射和标准宇宙学模型的观测结果相冲突。 这项建议的目标是发展和应用新的统计方法来分析红移和距离测量的集合，也称为特殊速度目录，其目标如下：（1）对宇宙学参数施加更强的约束;（2）更好地理解大尺度结构的动力学和宇宙的膨胀率;以及（3）在这一重要类型的宇宙学数据中检验系统学。拟议中的研究将澄清红移和距离测量是否实际上与标准模型相冲突，如果是，分歧的严重性和来源。 寻找膨胀率测定和观测到的局部体积运动之间的差异的原因对于更全面地了解宇宙非常重要。 这些冲突的解决可能会导致新的物理学或更好地理解一些尚未确定的系统在这个重要的宇宙学problem.This奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。

项目成果

Analysing the large-scale bulk flow using cosmicflows4: increasing tension with the standard cosmological model

使用 cosmicflows4 分析大规模整体流：使用标准宇宙学模型增加张力

• DOI: 10.1093/mnras/stad1984
• 发表时间: 2023
• 期刊: Monthly Notices of the Royal Astronomical Society
• 影响因子: 4.8
• 作者: Watkins, Richard;Allen, Trey;Bradford, Collin James;Ramon, Jr, Albert;Walker, Alexandra;Feldman, Hume A.;Cionitti, Rachel;Al-Shorman, Yara;Kourkchi, Ehsan;Tully, R. Brent
• 通讯作者: Tully, R. Brent

Peculiar velocity estimation from kinetic SZ effect using deep neural networks

• DOI: 10.1093/mnras/stab1715
• 发表时间: 2020-10
• 期刊: arXiv: Cosmology and Nongalactic Astrophysics
• 作者: Yuyu Wang;Nesar Ramachandra;Edgar M. Salazar-Canizales;H. Feldman;R. Watkins;K. Dolag