RUI: Advanced Numerical Simulations of Black Hole Accretion

1.黑洞所施加的引力是如此之强，以至于连光都无法逃脱。 当星星的核心在超新星爆炸中坍缩时，一些黑洞就形成了。 （超新星是一颗爆炸的星星，它短暂地发出与整个星系中所有数千亿颗恒星的总和一样明亮的光。） 超大质量黑洞，质量比太阳大数百万到数十亿倍，可能潜伏在大多数星系的中心。 黑洞会产生强大的潮汐力，可以撕裂离它太近的恒星。 黑洞本身并不发射辐射，但星星的分裂和由此产生的碎片的坠落都会产生相当大的能量。 许多吸积黑洞系统表现出快速准周期振荡（QPO）。 有些会产生非常高能量的等离子体射流，以接近光速的速度离开。 首席研究员将使用他改进的数字代码Cosmos++来模拟黑洞的吸积。 拟议研究的知识价值是，它将促进科学家对黑洞吸积和QPO性质以及此类系统中喷流特性的理解。 更广泛的影响包括学生参与研究项目，以及首席研究员参与各种公共外展活动，并将其结果纳入课堂教学。拟议的研究将采用广义相对论磁流体动力学（GRMHD）代码Cosmos++对黑洞吸积进行尖端模拟。 这项工作的智力价值是，它将推进天体物理学家对黑洞周围吸积盘的粘性和MHD处理之间的差异的理解，在一些这样的系统中观察到的准周期振荡（QPO）的性质，以及未对准吸积系统中喷流的方向。 主要研究者产生的更广泛影响？他通过各种公共外展活动，以及将他的成果融入课堂教学，让学生参与到RUI项目中。

1. The force of gravity that a black hole exerts is so strong that even light cannot escape. Some black holes form when the core of a star collapses in on itself during a supernova explosion. (A supernova is an exploding star that briefly shines as brightly as the combined light of all the hundreds of billions of stars in an entire galaxy.) Supermassive black holes, with masses millions to billions of times larger than the Sun's may lurk in the centers of most galaxies. A black hole exerts strong tidal forces that can rip apart stars that orbit it too closely. A black hole does not emit radiation itself, but the disruption of a star and infall of the resulting debris both generate considerable energy. Many accreting black hole systems exhibit rapid quasi-periodic oscillations (QPOs). Some produce jets of very high-energy plasma that speed away at velocities close to that of light. The Principal Investigator will use his improved numerical code Cosmos++ to perform simulations of accretion onto black holes. The Intellectual Merit of the proposed research is that it will advance scientists' understanding of black-hole accretion and of the nature of QPOs and properties of jets in such systems. The Broader Impacts include the involvement of students in the research project, as well as the Principal Investigator's participation in various public outreach activities and from the incorporation of his results into classroom lessons.2. The proposed research will employ the general relativistic magnetohydrodynamics (GRMHD) code Cosmos++ to perform cutting-edge simulations of black hole accretion. The Intellectual Merit of the work is that it will advance astrophysicists' understanding of the differences between viscous and MHD treatments of accretion disks around black holes, of the nature of quasi-periodic oscillations (QPOs) observed in some such systems, and of the orientation of jets in misaligned accretion systems. The Broader Impacts result from the Principal Investigator?s involvement of students in this RUI project, through a variety of public outreach activities, and from the incorporation of his results into his classroom lessons.