CAREER The Digital Sky: Bringing Cosmology into the Classroom

越来越明显的是，下一个十年将标志着观测宇宙学黄金时代的开始。如今，技术的进步使得以前所未有的细节绘制本地和遥远宇宙中星系的性质和分布成为可能。新的天文调查正在进行中，或即将完成，这将为数亿个物体产生图像和光谱，每个物体的测量覆盖了整个电磁频谱（从x射线波长到无线电频率）。在不久的将来，我们将不再局限于申请国家或私人设施的望远镜使用时间。相反，人们将能够“拨号”天空的一个区域（虚拟天文台正在成为现实）。这种新的研究模式将对本科生、研究生和博士后的研究产生深远的影响。这些新的多频巡天需要解决的一个基本问题是，星系是如何随着红移或回顾时间的变化而演化的。现有的光度和光谱调查为这种演化提供了一个框架，发现从z = 0的红移到z = 1的红移（光度增加10倍），总恒星形成率迅速增加。这些巡天的局限性在于，它们只覆盖了很小的天空区域（例如，迄今为止拍摄的最深的图像，哈勃深空，每面只有2角分），而且只包含了几百个星系。因此，除了星系演化的广泛特征之外，我们没有星系的数量来识别任何东西（即，我们的分析是有限的噪声），我们也没有足够的调查体积来判断我们是否看到了宇宙演化的真实反映（即，我们是有限的样本方差）。这些问题中的许多将在新的多色巡天中得到解决。仅斯隆数字巡天就将包含108个星系，覆盖了巨大的天空。这将是第一次有机会接触到大量的、统计上完整的星系样本，这些样本可以提供对本地和遥远宇宙的准确普查。通过使用新的统计技术，我们可以利用这些调查中的多色信息来估计星系的物理特性（即它们的红移，光谱类型和光度）。由此，我们可以直接追踪星系如何随着红移、星系类型和环境的变化而变化，从而指导星系形成和演化的理论。除了对星系形成和演化的物理学见解之外，这些数据将为学生们介绍天体物理科学开辟新的途径。这些多频巡天可以组合起来形成数字天空；一个涵盖了大部分夜空的恒星和星系的数据库，本科生和研究生都可以访问。从本质上讲，学生将有机会使用自己的望远镜，并可以按照自己的节奏探索或分析数据。鉴于这些新的天空调查具有巨大的研究和教学潜力，匹兹堡大学将开展一项旨在建立研究生和本科生天体物理学课程的研究和教育计划。这些计划的主要目标是：量化星系的属性（它们的光谱类型，恒星形成和光度）如何从z = 0到z = 1的红移演变，并确定是什么物理过程驱动了这些变化。o追踪低红移和中红移（z 1）的星系群集，作为回顾时间、星系类型和环境的函数，并将这些观测结果与当前星系形成和演化的宇宙学理论联系起来。o将新的虚拟天文台发展为本科生和研究生的研究和教学环境（“虚拟望远镜”）。它使学生能够按照自己的节奏进行在线天体物理数据库的探索。o将计算科学与天体物理学相结合，使研究生和本科生的思想和技术得以交流。该项目由天文科学学部资助

AST-9984924CONNOLLYIt is becoming increasingly apparent that the next decade will mark the beginning of a golden age for observational cosmology. Technological advances have now made it feasible to map the properties and distributions of galaxies in the local and distant Universe with unprecedented detail. New astronomical surveys are underway, or nearing completion, that will produce images and spectroscopy for hundreds of millions of objects each with measurements covering the full electromagnetic spectrum (from X-ray wavelengths through to radio frequencies). In the near future we will no longer be restricted to applying for telescope time at national or private facilities. Instead, people will be able to "dial-up" a region of the sky (a virtual observatory is becoming a reality). This new paradigm for undertaking research will have profound implications for research at the undergraduate, graduate and postdoctoral levels. One of the fundamental questions to be addressed with these new multi-frequency surveys is how do galaxies evolve as a function of redshift or lookback time. Extant photometric and spectroscopic surveys provide a framework for this evolution, finding a rapid increase in the total star formation rate from a redshift of z = 0 to redshift z = 1 (a factor of 10 increase in luminosity). The limitation of these surveys is that they extend over very small regions of the sky (for instance the deepest image ever undertaken, the Hubble Deep Field, subtends only 2 arcminutes on a side) and comprise only a few hundred galaxies. Consequently, we do not have the numbers of galaxies to identify anything more than the broad features of galaxy evolution (i.e. our analyses are shot noise limited) nor do we survey sufficient volume to be able to say whether we are seeing a true reflection of how the Universe evolves (i.e. we are sample variance limited).Many of these issues will be resolved by the new multicolor sky surveys. The Sloan Digital Sky Survey alone will contain 108 galaxies and cover a huge volume of the sky. For the first time, there will be access to large, statistically complete samples of galaxies that can provide an accurate census of the local and distant Universe. Through the use of novel statistical techniques we can use the multicolor information within these surveys to estimate the physical properties of galaxies (i.e. their redshifts, spectral types and luminosities). From this we can then directly trace how galaxies change as a function of redshift, galaxy type and environment and thereby guide the theories of galaxy formation and evolution.Beyond the insights into the physics of galaxy formation and evolution, these data will open new avenues for introducing students into the astrophysical sciences. These multifrequency surveys can be combined to form a digital sky; a database of stars and galaxies covering a large fraction of the night sky that is accessible to undergraduate and graduate students alike. Students will, in essence, have access to their own telescope and can explore or analyze the data at their own pace. Given the enormous research and teaching potential of these new sky surveys, a program of research and education designed to build the graduate and undergraduate astrophysics programs at the University of Pittsburgh will be carried out. The principle goals of these programs are:o To quantify how the properties of galaxies (their spectral types, star formation and luminosities) evolve from a redshift of z = 0 to z = I and to determine what physical processes drive these changes.o To trace the clustering of galaxies at low and intermediate redshifts (z 1) as a function of lookback time, galaxy type and environment and to relate these observations to current cosmological theories of galaxy formation and evolution.o To develop the new virtual observatories into an undergraduate and graduate research and teaching environment (a "virtual telescope"). One that enables students to undertake exploration of online astrophysical databases at their own pace.o To integrate computational sciences into astrophysics to enable a cross-fertilization of ideas and tech-niques at the graduate and undergraduate level.This project is funded by the Division of Astronomical Sciences.***