Accretion and Star Formation Induced by the Galactic Center Supermassive Black Hole Sgr A*

银河系中心超大质量黑洞 Sgr A* 引起的吸积和恒星形成

• 批准号: 1517246
• 负责人: Farhad Yusef-Zadeh
• 金额: $ 45.61万
• 依托单位: Northwestern University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-08-01 至 2022-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1517246&HistoricalAwards=false
• 关键词: Accretion; Star; Formation; Induced; Galactic

A longstanding problem in astrophysics is to understand how our own Milky Way Galaxy formed and developed throughout its lifetime. One important aspect of understanding the formation and evolution of the Milky Way is to study the supermassive black hole (called Sgr A*) at its center and how the black hole interacts with the rest of the Galaxy. The proximity of Sgr A* provides an excellent laboratory in which to investigate two intertwined processes: how stars are formed in the vicinity of the black hole and how their stellar winds are subsequently captured. This project will apply observation and theory to identify sites of current star formation very close to Sgr A* (within 2 parsecs) and will test ideas about how stars are formed in this environment.The investigators have an extensive history in communicating science and research to the public and are committed to continuing these efforts over the course of this project. The team also includes two graduate students who have developed Galactic center lessons, some of which incorporate the WorldWide Telescope (WWT) visualization system, for high school and community college classrooms throughout the Chicago area. The team will create and share two WWT tours on the topic of the Galactic center and the Milky Way Galaxy. Team members will use data, WWT tours and videos in public talks on the Galactic center black hole, a very popular topic to schools and numerous astronomical societies. The team will make FITS images related to this project available to professional and citizen science communities. They will make JPEG images from the FITS files and embed Astronomical Visual Metadata information into the image headers. The FITS and JPEG images, WWT tours and videos will be hosted at Northwestern University and will be accessible through a searchable content-managed web site.This project will examine star formation where the tidal and radiative effects by Sgr A* are significant. Their multi-wavelength approach (e.g., VLA, ALMA, VLT, SMA and CARMA) will examine water masers, compact H-II regions, SED fitting of protostars, proplyds and SiO outflows in the molecular ring and will identify protostellar outflows lying within 2 pc of Sgr A*. In addition, the team will determine the mass accretion rate onto Sgr A* by measuring the mass loss rate of ionized winds from young stars using radio techniques. The processes that lead to accretion are closely related to star formation in the nucleus of our Galaxy as well as in the nuclei of galaxies that host massive black holes.Detailed observations of the inner parsec of the Galactic center have primarily been conducted at infrared wavelengths using Keck and VLT telescopes. The recent upgrading of the VLA and commissioning of ALMA present an opportunity to apply novel techniques at radio and millimeter wavelengths to examine two related topics, star formation and accretion onto Sgr A*. These new capabilities will allow the team to use massive stars to register the radio and infrared frames with milliarcsecond accuracy and to determine the proper motion of stars orbiting Sgr A*. The accurate positioning of stars near the supermassive black hole will probe general-relativistic curvature of space-time by measuring periastron shift. The investigators will use a novel pragmatic approach to studying the disk mode of star formation near the tidally stressed environment of Sgr A*. The project may have far reaching implications on the nature of star formation and AGN activity in the nuclei of more active galaxies hosting massive black holes.

天体物理学中一个长期存在的问题是了解我们自己的银河系是如何形成和发展的。 了解银河系形成和演化的一个重要方面是研究其中心的超大质量黑洞（称为Sgr A*）以及黑洞如何与银河系的其他部分相互作用。 Sgr A* 的接近为研究两个相互交织的过程提供了一个极好的实验室：恒星如何在黑洞附近形成，以及它们的恒星风如何随后被捕获。 该项目将应用观测和理论来确定非常接近Sgr A*（在2秒差距内）的当前星星形成的地点，并将测试有关恒星如何在这种环境中形成的想法。调查人员在向公众传播科学和研究方面有着广泛的历史，并致力于在该项目的过程中继续这些努力。 该团队还包括两名研究生，他们开发了银河系中心课程，其中一些课程包括万维网望远镜（WWT）可视化系统，适用于整个芝加哥地区的高中和社区大学教室。 该团队将创建和分享两个关于银河系中心和银河系主题的WWT图尔斯之旅。 团队成员将使用数据，WWT图尔斯和视频在银河系中心黑洞，一个非常受欢迎的主题，学校和许多天文学会的公开讲座。 该团队将向专业和公民科学社区提供与该项目相关的FITS图像。 他们将从FITS文件中制作JPEG图像，并将天文视觉元数据信息嵌入图像标题中。 FITS和JPEG图像，WWT图尔斯和视频将在西北大学举办，并将通过一个可搜索的内容管理的网站访问。该项目将研究星星的形成，其中Sgr A* 的潮汐和辐射效应是显着的。 他们的多波长方法（例如，VLA、阿尔马、VLT、SMA和CARMA）将检查水脉泽、致密H-II区、原恒星的SED拟合、原恒星和分子环中的SiO外流，并将识别位于Sgr A* 2 pc范围内的原恒星外流。 此外，研究小组将通过使用无线电技术测量年轻恒星电离风的质量损失率来确定Sgr A* 的质量吸积率。 导致吸积的过程与我们银河系核心以及拥有大质量黑洞的星系核心的星星形成密切相关。银河系中心内秒差距的详细观测主要是使用凯克和VLT望远镜在红外波长下进行的。 最近VLA的升级和阿尔马的调试提供了一个机会，应用新技术在无线电和毫米波研究两个相关的主题，星星的形成和吸积到Sgr A*。 这些新功能将使研究小组能够使用大质量恒星以毫弧秒的精度记录无线电和红外帧，并确定围绕Sgr A* 运行的恒星的自行。 在超大质量黑洞附近精确定位恒星将通过测量近星点位移来探测时空的广义相对论曲率。 研究人员将使用一种新颖的实用方法来研究Sgr A* 潮汐压力环境附近的星星形成的磁盘模式。 该项目可能对星星形成的性质和活动星系核活动的性质产生深远的影响，这些活动星系核是大质量黑洞的所在。