Observational Signatures of Cosmic Strings

宇宙弦的观测特征

• 批准号: 2111738
• 负责人: Ken Olum
• 金额: $ 6万
• 依托单位: Tufts University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-09-01 至 2024-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2111738&HistoricalAwards=false
• 关键词: Observational; Signatures; Cosmic; Strings

This award funds some of the research activities of Professor Ken D. Olum at Tufts University.Cosmic strings are microscopically thin or even fundamental objects of cosmological length, which may or may not exist in our universe. Detection of cosmic strings would provide a window into fundamental physics at energies beyond the reach of any accelerator. Observation of a cosmic superstring network could provide a confirmation of the correctness of string theory, which is our current best theory for unifying the physics of gravity with the physics that governs the subatomic world. The best hope for discovering a cosmic string network is through observation of gravitational waves. The North American Nanohertz Observatory for Gravitational Waves (NANOGrav) has detected a signal that is likely be the first sign of a gravitational wave background formed by many sources throughout the universe. These sources could be pairs of giant black holes in the centers of galaxies, but they could also be cosmic string loops. Professor Olum will study the gravitational waves that would be emitted by cosmic strings and compare them with current and forthcoming NANOGrav observations. Professor Olum will also involve graduate students in this work and thereby train future generations of research physicists --- an activity which is in the national interest. The work will further connect studies of the universe with studies of the fundamental laws of nature.More technically, Professor Olum will simulate the evolution of cosmic string loops under the effects of gravitational self-interaction to see how their shapes and their gravitational wave spectra change over time. He will use a realistic population of cosmic string loops taken from his previous cosmic string network simulations. By combining the spectra from these loops, he will generate a gravitational wave background spectrum to be expected from cosmic strings and compare it with pulsar timing observations from the NANOGrav collaboration, of which he is a member. He will also study the velocities acquired by loops in reaction to anisotropic gravitational wave emission, the so-called "rocket effect", which is important for determining the degree of clustering of cosmic string loops in galaxies, and thus their potential observability.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.

该奖项为塔夫茨大学的肯·奥鲁姆（Ken D. Olum）教授的一些研究活动提供了资金。宇宙弦上是微观的甚至是宇宙学长度的基本对象，在我们的宇宙中可能存在也可能不存在。宇宙弦的检测将为任何加速器触手可及的能量提供基本物理的窗口。观察宇宙超弦网络可以确认弦理论的正确性，这是我们目前的最佳理论，用于将重力物理学与控制亚原子世界的物理学统一。 发现宇宙弦网络的最佳希望是观察引力波。 引力波（Nanograv）的北美纳米赫兹天文台检测到了一个信号，这可能是整个宇宙中许多来源形成的引力背景的第一个迹象。 这些来源可能是星系中心的巨型黑洞对，但也可能是宇宙弦乐环。 Olum教授将研究宇宙弦发射的引力波，并将其与当前和即将到来的纳米观测值进行比较。 Olum教授还将让研究生参与这项工作，从而培训子孙后代的研究物理学家，这是一项符合国家利益的活动。 这项工作将进一步将宇宙的研究与对自然基本定律的研究联系起来。从技术上讲，Olum教授将模拟宇宙弦循环在引力自相互作用的影响下的演变，以了解其形状和引力波光谱如何变化随着时间的推移。 他将使用从他以前的宇宙弦网模拟中获取的宇宙弦乐循环的现实种群。 通过将这些循环的光谱结合在一起，他将产生引力波背景光谱，从宇宙字符串中预期，并将其与纳米格拉夫协作中的脉冲星时定时观察进行了比较，他是他的成员。 他还将研究环路对各向异性引力波排放的反应，即所谓的“火箭效应”，这对于确定星系中宇宙弦乐环的聚类程度很重要，因此它们的潜在可观察性。反映了NSF的法定任务，并使用基金会的知识分子优点和更广泛的影响审查标准来评估值得支持。

项目成果

The NANOGrav 15 yr Data Set: Search for Signals from New Physics

• DOI: 10.3847/2041-8213/acdc91
• 发表时间: 2023-06
• 期刊: The Astrophysical Journal Letters
• 作者: A. Afzal;G. Agazie;A. Anumarlapudi;A. Archibald;Z. Arzoumanian;P. Baker;B. B'ecsy;J. Blanco-Pillado;L. Blecha;K. Boddy;A. Brazier;P. Brook;S. Burke-Spolaor;R. Burnette;R. Case;M. Charisi;S. Chatterjee;K. Chatziioannou;B. Cheeseboro;Siyuan Chen;T. Cohen;J. Cordes;N. Cornish;F. Crawford;H. Cromartie;K. Crowter;C. Cutler;M. DeCesar;D. DeGan;P. Demorest;Heling Deng;T. Dolch;B. Drachler;R. V. Eckardstein;E. Ferrara;W. Fiore;E. Fonseca;G. Freedman;N. Garver-Daniels;P. Gentile;K. A. Gersbach;J. Glaser;D. Good;Lydia Guertin;K. Gultekin;J. Hazboun;S. Hourihane;K. Islo;R. Jennings;A. Johnson;Megan L. Jones;A. Kaiser;D. Kaplan;L. Kelley;M. Kerr;J. Key;N. Laal;M. Lam;W. Lamb;T. Lazio;Vincent S. H. Lee;N. Lewandowska;Rafael R. Lino dos Santos;T. Littenberg;Tianyu Liu;D. Lorimer;Jing Luo;R. Lynch;Chung-Pei Ma;D. Madison;A. McEwen;J. McKee;M. Mclaughlin;N. McMann;B. W. Meyers;P. Meyers;C. Mingarelli;A. Mitridate;J. Nay;P. Natarajan;C. Ng;D. Nice;S. Ocker;K. Olum;T. Pennucci;B. Perera;P. Petrov;N. Pol;H. Radovan;S. Ransom;P. Ray;J. Romano;S. C. Sardesai;A. Schmiedekamp;C. Schmiedekamp;K. Schmitz;T. Schroder;L. Schult;B. Shapiro-Albert;X. Siemens;J. Simon;M. Siwek;I. Stairs;D. Stinebring;K. Stovall;Peter Stratmann;Jerry P. Sun;A. Susobhanan;J. Swiggum;Jacob M. Taylor;S. Taylor;T. Trickle;J. E. Turner;C. Unal;M. Vallisneri;Sonali Verma;S. Vigeland;H. Wahl;Qiaohong Wang;C. Witt;Davis Wright;O. Young;K. Zurek

The NANOGrav Search for Signals from New Physics: MCMC chains

NANOGrav 从新物理中寻找信号：MCMC 链

• DOI: 10.5281/zenodo.8083620
• 发表时间: 2023
• 期刊: Zenodo
• 作者: NANOGrav, The Collaboration

Nambu-Goto dynamics of field theory cosmic string loops

场论宇宙弦环的南部-后岛动力学

• DOI: 10.1088/1475-7516/2023/05/035
• 发表时间: 2023
• 期刊: Journal of Cosmology and Astroparticle Physics
• 影响因子: 6.4
• 作者: Blanco-Pillado, Jose J.;Jiménez-Aguilar, Daniel;Lizarraga, Joanes;Lopez-Eiguren, Asier;Olum, Ken D.;Urio, Ander;Urrestilla, Jon
• 通讯作者: Urrestilla, Jon