Probing Galaxy Feedback across Cosmic Time with a 3-Dimensional Census of Quasar Absorption Lines

布里特·伦德格伦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，在威斯康星大学麦迪逊分校开展一项研究和教育计划。天体物理学中一个长期存在的问题是理解星系在其一生中如何形成和发展-或演化-。这样的理解对于揭示我们的宇宙是如何进化的以及洞察我们银河系的起源是必要的。理解星系演化的一个重要方面是研究某些星系中新形成的恒星是如何与这些星系中心(核)的大质量黑洞相互作用的，这是这位研究员项目的中心主题。通过使用类星体吸收线(QAL)的最大样本，这位研究员将解决关于星系间介质的丰富历史及其与星系中恒星形成和活动星系核(AGN)反馈的联系的突出问题。类星体为大范围红移的星系环境提供了独特的无偏探测，但直到最近才有了光谱观测的高红移类星体的数密度，结合深星系调查的规模，提供了足够的统计数据来研究星系与红移大范围内近类星体视线的吸收特征之间的联系和星系的性质。通过参与斯隆数字天空调查III的重子振荡光谱测量(BOSS)，她将在未来三年获得16万个红移z 2.2类星体的光谱，这位研究员将提取红移z=0.35至4范围内金属吸收线的三维普查。她已经比现有的样品大了一个数量级，她将精确测量星际介质中最多产金属的数密度和等效宽度分布从红移z约4到现在的演变。利用这些数据和她目前参与的许多深部星系调查，她将揭示高红移QAL的典型银河系环境，并根据星系性质和红移限制星系和活动星系核外流的物理距离。总而言之，这些研究将可能彻底改变我们对恒星形成和活动星系核反馈的理解，以及它在大约90%的宇宙历史中星系和星际介质共同演化中的作用。这个项目的更广泛影响包括一个重要的教育组成部分。这位研究员将与麦迪逊著名的天文学推广中心威斯康星大学太空中心合作开展一项教育推广计划。在这个设施内，她将为6到8年级的学生举办一系列周末研讨会，使用她为之前的教育项目设计的经过良好测试的基于探究的现代天文学活动课程。除了这些以学生为中心的课程外，该研究员还将为当地高中科学教师举办一系列较短的晚间研讨会，旨在让教育工作者熟悉使用斯隆数字天空调查(Skyserver)的公共界面进行的活动。这些项目将为下一代科学家服务，为处于关键年龄的学生提供现代天文学研究的积极介绍，并为他们未来的教育工作者提供在高中课堂上促进进一步探索的工具。

Dr. Britt Lundgren is awarded an NSF Astronomy and Astrophysics Postdoctoral Fellowship to carry out a program of research and education at the University of Wisconsin-Madison. A longstanding problem in astrophysics is to understand how galaxies form and develop---or evolve---throughout their lifetimes. Such understanding is necessary to uncover how our Universe evolved and to gain insight into the origin of our own Milky Way Galaxy. One important aspect of understanding galaxy evolution is to study how large region of newly forming stars in certain galaxies interact with the massive black holes at the centers (nuclei) of these galaxies, which is the central theme of this fellow's project.By using the largest sample of quasar absorption lines (QALs), the fellow will address outstanding questions regarding the enrichment history of the intergalactic medium and its connection to feedback from star formation and Active Galactic Nuclei (AGN) in galaxies. QALs provide uniquely unbiased probes of galactic environments over vast ranges in redshift, but only recently has the number density of spectroscopically observed high-redshift quasars, combined with the scale of deep galaxy surveys, provided sufficient statistics to study the associations between galaxies and absorption features in proximate quasar sightlines over wide ranges in redshift and galaxy properties.Through her participation in the Sloan Digital Sky Survey III's Baryon Oscillation Spectroscopic Survey (BOSS), which will obtain spectra for 160,000 redshift z 2.2 quasars over the next three years, the fellow will extract a 3-dimensional census of metal absorption lines in the redshift range z = 0.35 to 4. Using this data set, already one order of magnitude larger than existing samples, she will precisely measure the evolution of the number density and equivalent width distribution for the most prolific metals in the intergalactic medium from redshift z around 4 to present. Leveraging these data with her existing participation in numerous deep galaxy surveys, she will reveal the typical galactic environments of QALs from high redshift and constrain the physical distances to which galaxy and AGN outflows extend as a function of galaxy properties and redshift. Together, these investigations will potentially revolutionize our understanding of feedback from star formation and AGN and its role in the co-evolution of galaxies and the intergalactic medium throughout about 90% of cosmic history.The broader impacts of this project include a significant educational component. The fellow will undertake a program of educational outreach in partnership with the UW Space Place, a well-established astronomy outreach center in Madison. Within this facility she will conduct a series of weekend workshops for students in grades 6 through 8 using a well-tested curriculum of inquiry-based modern astronomy activities that she designed for a previous educational program. The fellow will supplement these student-focussed sessions with a shorter series of evening workshops for local high school science teachers that are designed to familiarize educators with activities using the public interface to the Sloan Digital Sky Survey, the Skyserver. These programs will serve the next generation of scientists by providing students at a critical age with a positive introduction to modern astronomy research in addition to providing their future educators with the tools to foster further explorations in the high school classroom.