Global Dynamics of Accretion in High-Mass X-Ray Binary Systems

高质量 X 射线双星系统中吸积的全局动力学

• 批准号: 2308141
• 负责人: John Blondin
• 金额: $ 32.55万
• 依托单位: North Carolina State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-09-01 至 2026-08-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2308141&HistoricalAwards=false
• 关键词: Global; Dynamics; Accretion; Mass; Ray

Some of the most spectacular X-ray sources in the sky are High Mass X-ray Binaries (HMXBs). These are systems where a compact object, such as a neutron star or a black hole, rapidly orbits a hot, young, massive star. The gravitational pull of the compact object pulls material from the star which then spirals onto the compact object producing bright X-ray emission. The PI and his team will run computer simulations to better understand how much material falls onto the compact companion vs. how much escapes the gravitational field of the binary and is lost to interstellar space – this quantity is key for understanding how HMXBs evolve. This work will aid the interpretation of current observations of HMXBs by relating observational properties to the mass transfer rate. Much of this research will be done by undergraduates and will be used to introduce a diverse group of young students to astrophysics research. In addition to their research, the students will present their work at the North Carolina Museum of Natural Sciences and work with staff at the Digital Media Lab in the NC State library to create short YouTube videos. The PI will continue to build a series of short (10 minute) video lessons on fluid dynamics and computational physics that help students get started in this kind of research, with more senior students presenting some of the lessons. The investigator will use a new circumbinary gas dynamics code to investigate the global dynamics of mass and angular momentum accretion in HMXBs to connect observations to system parameters relevant to the evolution and classification of these systems. This work will focus both on well-observed systems like Vela X-1 as well as the broad class of systems ranging from Be X-ray binaries to supergiant fast X-ray transients and accreting black hole systems. By coupling together numerical models of the circumstellar gas dynamics (e.g., Roche lobe overflow, acceleration of the tidally enhanced wind from the donor star, X-ray heating and photoionization of the wind) and of the accretion flow (following the gas to small radii while conserving angular momentum), the investigators have developed a circumbinary gas dynamics code that can improve our understanding of the varied properties of HMXBs. This effort will enable simulations of gravitational accretion flows in three dimensions with sufficient detail to qualitatively describe the origin of any dynamical instability and to quantitatively characterize the resulting flux of mass and angular momentum accreted onto the compact companion or lost from the system in a variety of circumstances.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.

天空中一些最壮观的X射线源是高质量X射线双星(HMXB)。在这些系统中，致密物体，如中子星或黑洞，会迅速绕着一颗炽热、年轻、大质量的恒星运行。致密天体的引力将物质从恒星上吸走，然后螺旋上升到致密天体上，产生明亮的X射线辐射。PI和他的团队将运行计算机模拟，以更好地了解有多少物质落在紧凑的伴星上，以及有多少物质逃离双星的引力场并丢失到星际空间--这个数量是理解HMXB如何演化的关键。这项工作将有助于通过将观测性质与质量传输率联系起来来解释当前观测到的HMXB。这项研究的大部分将由本科生完成，并将用于向不同的年轻学生群体介绍天体物理学研究。除了他们的研究，学生们还将在北卡罗来纳州自然科学博物馆展示他们的工作，并与北卡罗来纳州州立图书馆数字媒体实验室的工作人员合作，制作YouTube短视频。PI将继续制作一系列关于流体力学和计算物理的简短(10分钟)视频课程，帮助学生开始这类研究，由更多的高年级学生介绍一些课程。研究人员将使用一种新的周二进制气体动力学代码来研究HMXB中质量和角动量吸积的全球动力学，将观测结果与与这些系统的演化和分类相关的系统参数联系起来。这项工作将集中在像船帆X-1这样的观测良好的系统，以及从Be X射线双星到超巨型快速X射线瞬变和吸积黑洞系统的广泛类别。通过将恒星周围气体动力学的数值模型(例如，罗氏叶溢出、来自供体恒星的潮汐增强风的加速、X射线加热和风光电离)和吸积流(在保持角动量的情况下跟随气体到小半径)的数值模型耦合在一起，研究人员开发了一个环行气体动力学程序，它可以改善我们对HMXB各种性质的理解。这项工作将能够以足够的细节在三维中模拟引力吸积流，以定性地描述任何动力学不稳定性的来源，并定量地表征在各种情况下附着在紧凑伴星上或从系统中丢失的由此产生的质量和角动量的流量。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。