Mid-Infrared Observations of the Torus of Active Galactic Nuclei

天体物理学中的一个基本问题是活动星系核(AGN)中的黑洞是如何被注入燃料的，因为黑洞注入会影响星系的形成和演化。位于星系中心的活动星系核本身，被解释为有一个由气体和尘埃组成的环状结构，阻挡了来自内部的光线，并可能掩盖活动星系核的中心引擎(黑洞)。然而，天文学家并不完全了解环面的确切性质，用望远镜直接观察环面极其困难。在这项提议中，PI计划解决以下关键问题：(A)环是由什么材料组成的，它是如何与宿主星系恒星之间的其余气体和尘埃联系在一起的？(B)环面性质，如几何形状和厚度，如何取决于活动星系核的亮度？(C)环中尘埃的性质是否随活动星系核的亮度而改变？和(D)星系中心活动星系核附近的恒星形成在进食和/或阻止活动星系核方面起什么作用？对这些问题的回答将有助于深入了解活动星系核是如何由星系中的气体提供燃料的，以及这可能如何影响星系本身的形成。通过PI的合作者网络，拟议的工作将有助于进一步加强发展中国家墨西哥在天文学方面的联系，并通过与西班牙和墨西哥的联系促进说西班牙语的美国团队成员的参与，主要是西班牙裔。国际天文学协会还计划与当地高中教师合作，加强他们对天文主题的理解和教学。通过这种方式，他希望接触到圣安东尼奥地区的当地学童，这是一个高度多样化的地区，提供高质量的科学内容，并鼓励学生(包括代表不足的少数族裔)追求科学领域。其目的是利用有趣的天文内容作为进入STEM科目的“门户”。中红外(MIR：7-26微米)波长的观测是必不可少的，因为环面截获了从黑洞附近发射的大量电磁辐射，并在该波段重新辐射它。和平研究所的设施，如8米斯巴鲁望远镜和格伦望远镜加那利阿斯(GTC)提供了探测高空间分辨率的和平波段活动星系核中心的可能性。假设活动星系核中尘埃呈块状分布的模型在解释MIR排放方面取得了重大进展。高分辨率观测将有助于约束模型参数，并提供对环面物理属性的洞察。这项提议将资助分析GTC上约100小时的保证时间(GT)和额外180小时的ESO-GTC时间(ESO和GTC共同分配的时间，作为西班牙提升到ESO成员资格的一部分以竞争性方式授予)。这将与来自双子座的档案数据相结合，以解决AGN研究中的一个关键问题。我们将详细了解环面、活动星系核/黑洞的燃料过程及其与环面的关系(甚至是环面的形成)、与宿主星系的相互作用以及其他星系中的尘埃化学。基于当前数据的模拟，为下一代设施(如索非亚、JWST、TMT等)准备新的观测数据都是有计划的。

A fundamental question in astrophysics is how black holes in active galactic nuclei (AGN) are fueled, because black hole fueling affects how galaxies are formed and evolve. The AGN themselves, lying at the very center of the galaxies, are explained as having a torus of gas and dust that blocks light from the inside, and can obscure the AGN central engine (the black hole). However, astronomers don't fully understand the exact properties of the torus, and directly viewing the torus with telescopes is extremely difficult. In this proposal, the PI plans to address the key questions of: (a) What material makes up the torus, and how is it connected to the rest of the gas and dust between the stars of the host galaxy? (b) How do the torus properties, such as geometry and thickness, depend on the brightness of the AGN? (c) Do the properties of the dust in the torus change with the AGN brightness? and (d) What is the role of star formation near the AGN in the centers of galaxies in feeding and/or blocking AGN? Answers to these questions will provide insight into how the AGN is fueled by gas in the galaxy and how that might have an impact on the formation of the galaxy itself. Through the PI's network of collaborators, the proposed work will aid in furthering links in astronomy in the developing nation of Mexico, and it promotes involvement of US Spanish-speaking team members, primarily Hispanics, through connections with Spain and Mexico. The PI also plans to work with local high-school teachers to enhance their understanding and teaching of astronomical topics. In this way, he hopes to reach local school children in the San Antonio area, an area of high diversity, providing high quality scientific content, and encouraging the students (including underrepresented minorities) to pursue scientific fields. The intent is to use the interesting astronomical content as a "gateway" to STEM subjects. Observations at mid-infrared (MIR: 7-26 microns) wavelengths are essential, as the torus intercepts a large amount of electromagnetic radiation emitted from near the black hole and re-radiates it in this waveband. MIR facilities such as the 8m Subaru telescope and the Gran Telescope Canarias (GTC) offer the possibility to probe the centers of AGN at MIR wavelengths with high spatial resolution. Models assuming clumpy dust distribution in AGN are making significant progress explaining MIR emission. High-resolution observation will help constrain model parameters and provide insight into torus physical properties. This proposal would fund analysis of data from ~100 hours of guaranteed time (GT) on the GTC and an additional 180 hours of ESO-GTC time (jointly ESO and GTC allocated time, competitively awarded as part of Spain's ascension to ESO membership). This would be combined with archival data from Gemini to tackle a key problem in AGN research. A detailed understanding of the torus, the AGN/black hole fueling process and its relationship to (or even creation of) the torus, the interaction with the host galaxy, and dust chemistry in other galaxies will be constructed. Simulations based on current data to prepare new observations for next generation facilities (such as SOFIA, JWST, TMT, etc.) are planned.