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

多年来的研究表明，星系中超大质量黑洞的大小与星系本身的大小有关，这或许并不令人惊讶，但也与星系的外观(类型)有关。然而，黑洞质量通常是通过研究银河系中恒星的运动来计算的，最近的研究表明，银河系中恒星棒的存在会导致恒星速度的显著扰动，这一点还没有被考虑在内。这导致了一种高估质量的偏差，并可能掩盖星系类型的影响。该奖项支持开发一种新的数值方法，而不会受到这个问题的困扰。与其他方法的比较和整个工作过程中的仔细检查将为未来更好地理解星系及其中心黑洞的共同进化奠定基础。该项目将致力于纠正这一混淆因素，以了解黑洞(BH)和星系的共同进化如何依赖于宿主星系的形态类型。最近的研究表明，棒状星系独特的轨道结构使视线速度分布发生了显著变化，但尽管现有的动态BH质量测量的螺旋星系中有近60%包含棒状星系，但所有这些估计都是使用轴对称模型得出的，这些模型不能解释这种棒状星系。由此产生的系统性高估偏差可能会掩盖对宿主星系形态的依赖。这项研究将(A)开发第一个能够准确确定条形盘星系中BH质量的恒星动力学轨道叠加程序；(B)运行高分辨率自洽N体模拟条形星系，并产生用于验证新程序的模拟运动学数据集；(C)改进几个条形星系中的BH质量测量；以及(D)利用独立混响映射(RM)估计，获得第一个附近两个星系的恒星动力学BH质量测量结果。建立一个新的代码是至关重要的，因为：(1)预测的高估可以与散射相媲美，从而可以掩盖BH增长机制的真正差异；(2)使用恒星动力学来确认Rm BH估计对于未来只有Rm可能的高红移估计是重要的；以及(3)特定星系的准确BH质量对于模拟X射线发射气体的吸积物理至关重要。这个多方面的项目，包括N体模拟、代码开发和真实数据的建模，将给研究生提供广泛和强大的技术技能，这是成功职业生涯所必需的。其他活动将通过大学教育学院为未来的小学教师提供坚实的STEM(科学、技术、工程、数学)基础，通过新开发的课程让非理科专业的本科生参与进来，并利用夏令营激励高中生在大学学习STEM学科。

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.