Black Hole Feedback and Galaxy Formation

Nagamine博士将把他对数百光年范围内新形成星系的流体动力学模拟与共同研究者Proga博士的模拟结合起来。Proga博士的模拟跟踪了黑洞中心几光年范围内的盘状吸积。为了在它们之间架起8个数量级的桥梁，这些计算将通过使用“放大”技术以更高的分辨率连续重新模拟一个有趣的体积，在中等规模上运行。在最大规模的模拟中，黑洞既是通过合并和吸积气体而增加质量的沉降粒子，也是能量、动量和紫外线辐射的来源。“汇”和“源”两项都将用近似公式表示；模型的预测结果将与星系间气体的观测结果以及每次红移时观测到的活动星系核的数量进行比较。作为一个新颖的方面，PI将计算年轻恒星和活动核的紫外线辐射如何传播到星系间气体中。星系尺度的模拟将用于发现气体流入内部星系的速度有多快。这为最后的计算提供了一个外部边界条件，它描述了中心黑洞周围的吸积盘。在最后阶段，研究小组可以计算出黑洞应该向星系气体中注入多少辐射和动量。这将是第一次计算黑洞是如何进食和发光的，当它位于一个星系的中心时，根据宇宙学的预测，这个星系本身正在与其他星系合并。一名研究生和一名博士后将通过参与研究而得到培训。本科生将参加nsf资助的本科生暑期研究经历项目。永胺博士将帮助规划一个新的公共天文馆在UNLV校园，并将设计宇宙学展览。该团队将从模拟中生成图像和电影，用于公共宣传；他们的目标是为IMAX电影制作足够高质量的视觉效果。两位调查人员将继续在联卢大学组织的一系列公开讲座中发表演讲。

Dr. Nagamine will combine his hydrodynamic simulations of newly-forming galaxies in regions hundreds of light years across with those of co-investigator Dr. Proga, which follow disk accretion within the central few light years around a black hole. To bridge the 8 orders of magnitude in scale between them, these calculations will be linked by runs at intermediate scale using a 'zoom-in' technique of successively re-simulating an interesting volume at much higher resolution. Black holes are included in the largest-scale simulations both as sink particles that grow in mass by merging and by accreting gas, and as sources of energy, momentum and ultraviolet radiation. Both 'sink' and 'source' terms will be represented by approximate formulas; the model predictions will be compared with observations of the intergalactic gas, and the numbers of active galactic nuclei seen at each redshift. As a novel aspect, the PI will calculate how the ultraviolet radiation of young stars and active nuclei propagates out into the intergalactic gas. Galaxy-scale simulations will be used to find how fast gas will flow into the inner galaxy. This provides an outer boundary condition for the last calculation, which describes the accretion disk around the central black hole. At this last stage, the group can calculate how much radiation and momentum the black hole should inject back into the gas of the galaxy. These will be the first calculations of how a black hole feeds and shines, when it is in the center of a galaxy that is itself merging with others according to cosmological predictions.A graduate student and a postdoctoral fellow will be trained by their involvement in the research. Undergraduate students will participate through an NSF-funded summer Research Experiences for Undergraduates program. Dr. Nagamine will help to plan a new public planetarium on the UNLV campus, and will design cosmology exhibits for it. The team will generate images and movies made from the simulations, for use in public outreach; they aim to produce visualizations of sufficient quality for an IMAX movie. Both investigators will continue to give public lectures in a series organized by UNLV.