Probing Extreme Physics Through Analysis of Neutron Star Surface Emission

通过分析中子星表面发射来探索极端物理

• 批准号: 0708424
• 负责人: Michael Miller
• 金额: --
• 依托单位: University of Maryland, College Park
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-09-01 至 2011-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0708424&HistoricalAwards=false
• 关键词: Probing; Extreme; Physics; Through; Analysis

Neutron stars present some of the most extreme physical conditions in the universe - conditions which cannot be studied through laboratory experiments here on Earth. Here Dr. Bhattacharyya and collaborators will focus on three specific problems which can only be addressed by studying neutron stars: (1) understanding the super-dense cold matter in neutron star cores, which may contain exotic matter (e.g., meson condensates, deconfined quarks, etc.). This has been an unsolved problem of fundamental physics for more than 35 years, and can be resolved only by accurate measurements of the mass, radius and spin period of a neutron star. (2) Performing strong-field tests of the predictions of general relativity. (3) Understanding how thermonuclear flames spread on neutron star surfaces during type I X-ray bursts, which will also provide unique opportunities to probe the behavior of magnetized atmospheres under extreme conditions. These studies will have significant impact on various fields, including nuclear physics, magnetohydrodynamics, and general relativity. In the first two years, the team will carry out: an exhaustive analysis of type I burst data from the Rossi X-ray Timing Explorer (RXTE) satellite, and the simultaneous fitting of the observed fast timing features and broad-band spectra with the rigorous models already developed by the team (this will constrain properties of neutron stars); a careful analysis of data from Chandra and X-ray Multi-Mirror-Newton satellites to determine the chemical composition of the fuel and other aspects of the type I bursts, and to search for spectral lines from neutron star surfaces (both will be useful for constraining stellar parameters); detailed theoretical study of the shapes of surface spectral lines for prescribing a realistic way to detect the frame-dragging predicted by general relativity, and estimation of the capabilities of future X-ray satellites for this detection; and finding significant time evolution of various burst properties for each type I burst in the RXTE data archive (this will aid in the understanding of flame spreading). In the third year, the team will focus on: the modeling of persistent pulsation light curves from accreting millisecond pulsars (this will involve general relativistic ray tracing in a scattering corona, and will constrain neutron star parameters); and simulation of flame spreading including the effects of magnetic fields, in order to model the RXTE data. These projects may yield a breakthrough in the behavior of matter in extreme conditions.It is expected that this research will have an impact on several fields of physics. It has strong potential to establish collaborations among different disciplines and institutions. The team will disseminate the scientific results through publications in journals and presentations at scientific meetings. The team will also discuss their findings in popular journals, and give public talks at the University of Maryland Observatory and in other forums.

中子恒星呈现宇宙中一些最极端的物理条件 - 无法通过地球上的实验室实验研究。在这里，Bhattacharyya博士和合作者将重点关注三个特定问题，只能通过研究中子星来解决，（1）了解中子恒星核中的超密集冷物质，可能包含异国情调的物质（例如，梅森式凝胶，米es旋源，否定性的夸克夸克， ETC。）。这已经是基本物理学的一个未解决的问题已有35年以上，只能通过准确测量中子星的质量，半径和自旋时期来解决。 （2）对一般相对性的预测进行强场测试。 （3）了解在I型X射线爆发期间，热核火焰如何在中子恒星表面上散布，这也将提供独特的机会，以探测极端条件下磁化大气的行为。这些研究将对包括核物理学，磁性水力学和一般相对论在内的各个领域产生重大影响。在最初的两年中，团队将进行：对Rossi X射线计时浏览器（RXTE）卫星的I型爆破数据的详尽分析，以及观察到的快速定时功能和与宽带光谱的同时拟合团队已经开发的严格模型（这将限制中子星的特性）；仔细分析来自钱德拉和X射线多晶型牛顿卫星的数据，以确定燃料的化学成分和I型爆发的其他方面，并从中子星表面搜索光谱线（两者都对约束恒星参数）；详细的理论研究了表面光谱线的形状，用于规定一种现实的方法，以检测一般相对性预测的框架拖累，以及对未来X射线卫星的能力的估计；并在RXTE数据存档中找到每种I类型爆发的各种爆发特性的大量时间演变（这将有助于理解火焰扩散）。在第三年，团队将重点关注：持续的脉动光曲线对毫秒脉冲的建模（这将涉及一般相对论的射线追踪在散射电晕中，并限制中子星参数）；和模拟火焰扩散，包括磁场的影响，以模拟RXTE数据。这些项目在极端情况下可能会在物质的行为上取得突破。预计这项研究将对几个物理领域产生影响。它具有在不同学科和机构之间建立合作的强大潜力。该团队将通过科学会议上的期刊和演讲中的出版物来传播科学结果。该团队还将在流行期刊上讨论他们的发现，并在马里兰州的天文台和其他论坛上进行公开谈判。