The Origin of Supermassive Black Holes and their Influence on Dwarf Galaxies

黑洞是一种密度大得令人难以置信的物体，具有强大的引力。天文学家已经找到了令人信服的证据，证明包括我们银河系在内的大型星系在其中心都有巨大的黑洞。这些物体还可以发射大量的能量，可以加热和推动整个星系中的气体。因此，随着时间的推移，黑洞会对星系产生深远的影响。然而，关于巨型黑洞还有许多问题没有得到解答：它们是如何形成的？它们是如何生长的？它们是否能够永久性地阻止星系中恒星的形成？它们能影响它们所处星系周围神秘暗物质的分布吗？这个项目试图通过研究一个最小的星系样本来解决这些问题-被称为“矮星”-它们包含中心黑洞。矮星系有着和平的形成和相互作用的历史，这使得它们的中心黑洞以比大星系更被动的方式成长。因此，它们为早期宇宙中第一个黑洞的形成提供了重要线索。将比较有和没有能量发射黑洞的矮星样本，以评估黑洞活动对这些星系气体的影响。观测结果还将与计算机模型的预测进行比较，这些模型考虑了宇宙作为一个整体是如何演变的。参与该项目的科学家还将开展一项针对传统上较少参与科学的群体的推广计划。虚拟现实多感官资源将被创建，以帮助聋人和盲人体验宇宙。这些产品将被修改以吸引南加州的西班牙裔社区，并出口到支持PI正在进行的努力，向非洲马拉维的艾滋病孤儿教授天文学。一项联合观测/理论工作将研究具有活动星系核（AGN）特征的低质量星系中黑洞的生长。目标恒星质量在1000万到100亿太阳质量之间。该团队将收集一个样本AGN候选矮星，并使用光学和近红外波长的高空间分辨率光谱观测来确认它们是否真正包含AGN。将开发新的方法来估计这些难以捉摸的物体中的黑洞质量，并将其应用于样本。还将观察匹配的对照非活动星系核样本。这些数据将允许搜索和探测这些矮星系中的外流;活动星系核与非活动星系核物体的比较将提供黑洞反馈对矮星系气体含量影响的初步估计。宿主的其他关键结构特性，如颜色/金属丰度梯度和运动学，将被测量以探索反馈的其他可能影响。观测结果将与不同反馈模型（包括有无活动星系核）运行的矮星放大宇宙学数值模拟进行比较。模拟将不仅用于预测，而且还估计由于投影效应，光束大小和光谱分辨率的不确定性。该项目的目标可以概括为两点：1）帮助限制矮星系中黑洞的人口统计，2）了解黑洞反馈对这些星系结构特性的影响。该项目的预期结果可能会改变我们对矮星反馈的理解，通过揭示黑洞反馈到星际介质的能量耦合，并提供对流出的严格约束，这些约束可用于为下一代反馈理论模型提供信息。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Black holes are incredibly dense and massive objects with powerful gravity. Astronomers have found convincing evidence that large galaxies, including our own Milky Way, have giant black holes in their centers. These objects can also emit large amounts of energy that can heat and push the gas in entire galaxies. For this reason, black holes can have a profound effect on galaxies over time. There are many questions, however, regarding giant black holes that remain unanswered: How do they form? How do they grow? Are they capable of permanently shutting down the formation of stars in galaxies? Can they affect the distribution of the mysterious dark matter surrounding the galaxies where they live? This project seeks to address these questions by studying a sample of the smallest galaxies - known as "dwarfs" - that contain central black holes. Dwarfs have peaceful formation and interacting histories that allow their central black holes to grow in a more passive way than in large galaxies. Therefore, they provide important clues about the formation of the first black holes in the early universe. Samples of dwarfs with and without energy-emitting black holes will be compared to assess the effects of black hole activity on the gas of these galaxies. Observations will also be compared with predictions of computer models that take into account how the universe evolves as a whole. The scientists involved in this project will also conduct an outreach program targeted to groups traditionally less involved in the sciences. Virtual reality multi-sensory resources will be created to help the deaf and the blind experience the universe. These products will be adapted to engage the large Hispanic community in Southern California, and exported to support the PI's ongoing efforts to teach astronomy to AIDS orphan children in Malawi, Africa.A joint observational/theoretical effort will study the growth of black holes in low mass galaxies with signatures of an active galactic nuclei (AGN). The target stellar mass is in the range between ten million and ten billion solar masses. The team will assemble a sample AGN candidate dwarfs and confirm whether they truly contain AGNs with the use of high spatial resolution spectroscopic observations in optical and near infrared wavelengths. New methods to estimate black hole masses in these elusive objects will be developed and applied to the sample. A matched control non-AGN sample will also be observed. The data will allow for the search and detection of outflows in these dwarfs; the comparison of AGN with non-AGN objects will provide the first estimates of the impact of black hole feedback on the gas content of dwarf galaxies. Other key structural properties of the hosts, such as color/metallicity gradients and kinematics, will be measured to explore other possible effects of feedback. Observational results will be compared to zoom-in cosmological numerical simulations of dwarfs run with different feedback models, including with and without AGN. Simulations will be used not only as predictions, but also to estimate uncertainties due to projection effects, beam size and spectral resolution. The goals of the project can be summarized in two points: 1) help constrain the demographics of black holes in dwarfs, 2) understand the impact of black hole feedback on the structural properties of these galaxies. The expected results of this project can potentially transform our understanding of feedback in dwarfs by shedding light on the energy coupling of black hole feedback to the interstellar medium and providing tight constraints on outflows that can be used to inform the next generation theoretical models of feedback. Further legacy that includes a detailed survey of the stellar properties and kinematics of dozens of dwarf galaxies within 200 Mpc is also expected.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.