Black holes in barred galaxies: the Rosetta Stones of secular galaxy evolution

棒状星系中的黑洞：世俗星系演化的罗塞塔石碑

• 批准号: 1515001
• 负责人: Monica Valluri
• 金额: $ 39.95万
• 依托单位: Regents of the University of Michigan - Ann Arbor
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-09-01 至 2020-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1515001&HistoricalAwards=false
• 关键词: Black; holes; barred; galaxies; Rosetta

Studies have been showing for some years that the size of a supermassive black hole in a galaxy is correlated with the size of the galaxy itself, perhaps unsurprisingly, but also with the appearance (the 'type') of the galaxy. However, the black hole mass is normally calculated by studying the motions of stars in the galaxy, and recent work suggests that the presence of a bar in the galaxy causes a significant perturbation in the stellar speeds, which has not been taken into account. This leads to a bias that over-estimates the mass and can hide the effect of galaxy type. This award supports development of a new numerical method that does not suffer from this problem. Comparison with other methods and careful checks throughout the work will lay the foundations for future better understanding of the co-evolution of galaxies and their central black holes.This project will work to correct this confounding factor in understanding how the co-evolution of black holes (BH) and galaxies depends upon the host galaxy's morphological type. Recent studies show that the unique orbital structure of a bar makes significant changes in line-of-sight velocity profiles, but although nearly 60% of spiral galaxies with existing dynamical BH mass measurements contain bars, all of those estimates were derived using axisymmetric models that do not account for the bar. The resultant systematic over-estimation bias can mask dependencies on host galaxy morphology. This study will (a) develop the first stellar dynamical orbit superposition code capable of accurately determining BH masses in barred disk galaxies; (b) run high resolution self-consistent N-body simulations of bars and generate mock kinematic datasets for validating the new code; (c) improve the BH mass measurements in several barred galaxies; and (d) obtain the first stellar dynamical BH mass measurements for two nearby galaxies with independent reverberation mapping (RM) estimates. Building a new code is crucial because: (1) the predicted over-estimate is comparable to the scatter and thus can mask genuine differences in BH growth mechanisms; (2) using stellar dynamics to confirm RM BH estimates is important for future high redshift estimates where only RM is possible; and (3) accurate BH masses for specific galaxies are critical for modeling the accretion physics of X-ray emitting gas.This multi-faceted project, involving N-body simulations, code development, and the modeling of real data, will give the graduate student involved the broad and strong technical skills necessary for a successful career. Other activities will provide future elementary school teachers with strong STEM (Science, Technology, Engineering, Mathematics) foundations through the university's school of education, involve non-science major undergraduates through a newly-developed course, and use a summer camp to inspire high school students to pursue STEM disciplines in college.

多年来，研究已经表明，银河系中超质量黑洞的大小与星系本身的大小相关，也许毫不奇怪，但也与银河系的外观（“类型”）相关。 然而，黑洞质量通常是通过研究星系中恒星运动来计算的，最近的工作表明，银河系中的棒的存在会引起恒星速度的明显扰动，尚未考虑到尚未考虑。 这导致偏见过度估计质量并可以隐藏星系类型的效果。 该奖项支持开发一种新的数值方法，该方法不会遭受此问题的困扰。 在整个工作中与其他方法和仔细的检查进行比较，将为将来更好地理解星系的共同发展及其中央黑洞的基础。该项目将有效地纠正这一混杂因素，以了解黑洞（BH）的共同发展和星系如何取决于宿主星系的形态类型。 最近的研究表明，棒的独特轨道结构在视线速度曲线方面有重大变化，但是尽管将近60％的带有现有动力学BH质量测量值的螺旋星系包含棒，但所有这些估计都使用不考虑条形的轴对称模型得出。 由此产生的系统过度估计偏差可以掩盖对宿主星系形态的依赖性。 这项研究将（a）开发第一个恒星动力学轨道叠加代码，能够准确确定禁止磁盘星系中的BH质量； （b）运行棒的高分辨率自一致的n体仿真，并生成模拟运动学数据集以验证新代码； （c）改善几个禁止星系的BH质量测量； （d）获得具有独立的混响映射（RM）估计值的两个附近星系的第一个恒星动力学BH质量测量值。 构建新代码至关重要，因为：（1）预测的过度估计与散布相当，因此可以掩盖BH增长机制的真实差异； （2）使用恒星动力学确认RM BH估计值对于将来只有RM才有可能的高红移估计很重要； （3）针对特定星系的准确BH质量对于建模X射线发射气体的积聚物理学至关重要。此多面项目涉及N身体模拟，代码开发和真实数据的建模，将使研究生涉及成功职业所必需的广泛而强大的技术技能。 其他活动将通过大学教育学院为未来的小学教师提供强大的STEM（科学，技术，工程，数学）基础，涉及非科学专业的大本科生，并通过新成长的课程，并使用夏令营来激发高中生在大学中追求STEM学科。