Emission-lines from AGN&Starbursts: new steps to understanding their message

AGN 的发射线

• 批准号: 1412155
• 负责人: Gary Ferland
• 金额: $ 48.63万
• 依托单位: University of Kentucky Research Foundation
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-09-01 至 2018-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1412155&HistoricalAwards=false
• 关键词: Emission; lines; AGN& Starbursts; new

Much of modern astrophysics involves the interaction of electromagnetic radiation (light) with diffuse clouds of gas around stars, in galaxies and in the spaces between them. The radiation interacts with the atoms in the gas, heats the gas and sometimes ionizes and excites the atoms. The gas then emits light which, in turn, interacts with the gas. The detailed physical processes involved in these interactions are enormously complex and vary with the gas' temperature, density and chemical abundance. Understanding these processes and their interplay with the radiation allows astrophysicists to deduce the physical conditions in the gas clouds and the characteristics of the source of the radiation. Dr. Ferland is one of the world's experts in the study of the interplay of light and ionized gas and for thirty years he has been developing an open-source, publicly-available computer simulation tool called "Cloudy." Cloudy is used by hundreds of astronomers and astrophysicists in studies of diverse regions from star-forming regions to the light-emitting regions surrounding and excited by the supermassive black holes at the centers of active galaxies (Active Galactic Nuclei or AGN) and quasars. Cloudy has been used in the training and research of several generations of students and young researchers. This award will support a major upgrade of the Cloudy code that will improve its performance and range of applicability. The upgrade will potentially allow it to be used in simulations of gas in dense plasmas such as star-forming regions and will allow better calculation of the emission of light from gas near the heart of quasars.This is a time of unprecedented discovery in understanding the central regions of Active Galactic Nuclei and Starburst galaxies across the electromagnetic spectrum. Reverberation mapping of the Broad Lined Region, using optical H I recombination lines at low redshift, and collisionally excited lines at high redshift, have led to catalogs of supermassive black hole masses. These in turn make possible investigations of key questions such as the evolution of black hole mass, the role of AGN feedback, and the interplay between the evolution of the black hole and surrounding galaxy. The Atacama Large Millimeter/Sub-millimeter Array (ALMA) makes it possible to routinely study radio recombination lines from both AGN and Starburst galaxies, probing sources of ionizing radiation in dust-shrouded regions. ALMA can further probe molecular emission from both star-forming regions and the AGN molecular torus. This project will develop the theoretical tools needed to understand these emission-line observations and incorporate them into Cloudy, which has been designed to solve these plasma, chemistry, radiation transport, and dynamics problems simultaneously and self consistently, building from the foundation of individual atomic and molecular processes. The advances to be undertaken are motivated by recent discussions with the dense plasma / magnetic fusion communities. Methods and data they have developed will dramatically improve the numerical simulations at surprisingly low cost. These significantly improved simulations will be applied to models of the BLR, star-forming regions,and to associated molecular regions.

许多现代天体物理学涉及到电磁辐射（光）与恒星周围、星系和星系间空间弥漫的气体云的相互作用。辐射与气体中的原子相互作用，加热气体，有时电离并激发原子。然后气体发出光，而光又与气体相互作用。这些相互作用所涉及的详细物理过程极其复杂，并随气体的温度、密度和化学丰度而变化。了解了这些过程及其与辐射的相互作用，天体物理学家就可以推断出气体云中的物理条件和辐射源的特征。费兰博士是世界上研究光与电离气体相互作用的专家之一，30年来，他一直在开发一种开源、公开的计算机模拟工具，名为“Cloudy”。云天被数以百计的天文学家和天体物理学家用于研究不同的区域，从恒星形成区域到围绕在活动星系（活动星系核或AGN）和类星体中心的超大质量黑洞周围并被其激发的发光区域。Cloudy已被用于几代学生和年轻研究人员的培训和研究。该合同将支持对Cloudy代码进行重大升级，以提高其性能和适用范围。这次升级将有可能使其用于模拟致密等离子体中的气体，如恒星形成区域，并将允许更好地计算类星体中心附近气体的光发射。在了解活动星系核和星暴星系在电磁波谱上的中心区域方面，这是一个前所未有的发现。利用低红移的光学H I重组线和高红移的碰撞激发线对宽衬区进行混响映射，得出了超大质量黑洞质量的目录。这些反过来又使得对关键问题的研究成为可能，比如黑洞质量的演变，AGN反馈的作用，以及黑洞与周围星系的演变之间的相互作用。阿塔卡马大型毫米/亚毫米阵列（ALMA）使常规研究AGN和星暴星系的无线电重组线成为可能，探测尘埃覆盖区域的电离辐射源。ALMA可以进一步探测恒星形成区和AGN分子环面的分子发射。该项目将开发理解这些发射在线观测所需的理论工具，并将它们整合到Cloudy中，该项目旨在同时解决这些等离子体、化学、辐射传输和动力学问题，并从单个原子和分子过程的基础上自我一致地解决这些问题。最近与致密等离子体/磁融合团体的讨论推动了将要进行的进展。他们开发的方法和数据将以惊人的低成本显著改善数值模拟。这些显著改进的模拟将应用于BLR、恒星形成区域和相关分子区域的模型。