Solving the Puzzle of the Galactic Bar

解开银河酒吧之谜

• 批准号: 1203017
• 负责人: Gail Zasowski
• 金额: $ 8.9万
• 依托单位: Zasowski Gail
• 依托单位国家: 美国
• 项目类别: Fellowship Award
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-09-01 至 2015-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1203017&HistoricalAwards=false
• 关键词: Solving; Puzzle; Galactic; Bar

Dr. Gail Zasowski is awarded an NSF Astronomy and Astrophysics Postdoctoral Fellowship to carry out a program of research and education at The Ohio State University (OSU). One of the greatest unresolved puzzles of our Milky Way Galaxy (MW) is the nature of the long central bar: its structure, dynamics, and stellar chemical composition. The bar is expected to have a significant impact on mass and abundance distributions in the inner Galaxy, which are used to characterize the MW's global properties and their relation to those of other galaxies. This characterization is crucial for understanding not only the MW but also general galactic evolution because the proximity and accessibility of the MW makes it the most powerful resource that investigators have to develop models of galaxy formation and aging. Unfortunately, a thorough understanding of the MW's fundamental properties has been precluded as its inner regions, where most of the stellar mass is located, are behind the thick dust of the midplane. New infrared (IR) data from multiple photometric and spectroscopic surveys are providing a way to probe these inner regions at a level never before possible. The fellow plans a comprehensive analysis of the inner MW that focuses on the spatial, dynamical, and chemical properties of the influential but poorly-understood long bar. This project will take advantage of the unprecedented availability of both photometric and spectroscopic infrared observations of the inner MW midplane, including unique high resolution IR spectra from the Sloan Digital Sky Survey III's Apache Point Observatory Galactic Evolution Experiment (APOGEE).The fellow will combine near- and mid-IR photometry to produce an extinction-corrected catalogue of stars spanning the long bar and outer bulge, and she will use this catalogue to make the first stellar density map of these regions that is capable of measuring the long bar's position, axial ratios, and structural coherence. She will collect radial velocities with APOGEE for a large sample of red clump (RC) giants in the long bar and compare them to kinematical predictions from N-body and stellar dynamics models to measure the bar's systematic velocity, dispersion, and dynamical coherence. Of particular interest are the kinematics of the "transition regions" where resonances influence the bar-bulge and bar-disk relationships. Finally, the fellow will use the APOGEE-derived metallicities and abundances of the RC sample to measure the metallicity distribution along the bar, including the presence of multiple stellar populations. The result will be a complete picture of the long bar's spatial, dynamical, and chemical distributions, which can be used to establish the bar's properties compared to external galactic bars, along with its stellar properties and mixing efficiency.The broader impacts of this project include a significant educational component. The fellow will leverage OSU's partnership with Ohio's 4-H program to demonstrate to children and the general public that science and scientific inquiry are fun, relevant to their lives, and perhaps most importantly, accessible to all. In partnership with the Ohio 4-H state office, the fellow will contribute to two projects teaching scientific concepts through interactive activities, with an emphasis on those that can be easily done in the home. First, she will develop astronomy-themed activities for an annual summer Space Camp targeted at middle-school students. Second, she will combine astronomy-themed activities with suitable background information and evaluation metrics into a Space Science Project Book for 4-H's Project Book series, which encourages students to select, design, and evaluate their own learning experiences beyond the classroom. The close association of 4-H with rural and often economically disadvantaged schools means that the materials that she develops will impact the scientific literacy of these underserved communities.

Gail Zasowski博士被授予美国国家科学基金会天文学和天体物理学博士后奖学金，在俄亥俄州立大学（OSU）开展研究和教育项目。我们银河系（MW）最大的未解之谜之一是中央长条状星系的性质：它的结构、动力学和恒星的化学成分。该条形预计会对内星系的质量和丰度分布产生重大影响，这些分布被用来表征MW的整体特性及其与其他星系的关系。这一特征不仅对理解星系黑洞，而且对理解整个星系的演化都至关重要，因为星系黑洞的接近性和可达性使其成为研究人员开发星系形成和衰老模型的最强大资源。不幸的是，由于其内部区域（大部分恒星质量所在的地方）位于中间层厚厚的尘埃后面，对MW基本特性的彻底了解已经被排除。来自多个光度和光谱调查的新红外（IR）数据提供了一种前所未有的水平探测这些内部区域的方法。该研究员计划对内部MW进行全面分析，重点关注有影响但知之甚少的长条形结构的空间、动力学和化学性质。该项目将利用前所未有的光度和光谱红外观测的内部MW中间层，包括独特的高分辨率红外光谱来自斯隆数字巡天III的阿帕奇点天文台银河演化实验（APOGEE）。这位研究员将结合近红外和中红外光度测定法，制作一份消光校正的恒星目录，涵盖长条状星系和外凸起状星系，她将利用这份目录制作这些区域的第一张恒星密度图，从而能够测量长条状星系的位置、轴向比和结构相干性。她将用APOGEE收集长条状星云中大量红团巨星的径向速度，并将其与n体和恒星动力学模型的运动学预测进行比较，以测量条状星云的系统速度、色散和动力学相干性。特别令人感兴趣的是“过渡区域”的运动学，其中共振影响条状-凸起和条状-圆盘关系。最后，该研究员将使用远地点gee衍生的金属丰度和RC样品的丰度来测量金属丰度沿棒的分布，包括多个恒星群的存在。结果将是一个完整的长棒的空间、动力学和化学分布的图像，可以用来建立与外部星系棒相比的长棒的特性，以及它的恒星特性和混合效率。这个项目更广泛的影响包括一个重要的教育组成部分。该研究员将利用俄勒冈州立大学与俄亥俄州4-H计划的合作关系，向儿童和公众展示科学和科学探究是有趣的，与他们的生活相关，也许最重要的是，所有人都可以接触到。与俄亥俄州4-H州办公室合作，该研究员将通过互动活动教授科学概念，重点是那些可以在家中轻松完成的项目。首先，她将为一年一度的中学生暑期太空营开发以天文学为主题的活动。其次，她将把以天文学为主题的活动与合适的背景信息和评估指标结合到4-H项目系列的空间科学项目书中，鼓励学生选择、设计和评估自己在课堂之外的学习经历。4-H与农村和经济条件较差的学校的密切联系意味着她开发的材料将影响这些服务不足社区的科学素养。