Gaia Data Flow System

盖亚是欧洲航天局的基石使命，将于2011年第四季度发射，寿命为5至6年。它的科学目标是通过对银河系及其周围十亿个物体的位置和速度进行普查，绘制出最大、最精确的银河系地图。因此，它将成为研究银河系结构和形成历史的基础，这是英国天文学研究的四大核心主题之一：星星的形成和银河系的发展。作为一项全面的调查使命，盖亚有望成为科学界最伟大的发现机器之一。它将在五年内平均监测每个目标物体（主要是恒星，小行星，星系和类星体）85次，精确绘制它们的距离，运动和亮度变化。预计它将发现数十万个新的天体，如太阳系外行星和被称为褐矮星的失败恒星。例如，在我们自己的太阳系中，盖亚预计将识别数万颗迄今未知的小行星。预期的发现还包括探测和描述数以万计的太阳系外行星系统。该调查将覆盖约1000万个星系和50万个遥远的类星体。它将进一步为广义相对论提供严格的新检验。盖亚数据处理是将卫星数据转化为天文学家可以分析以获得新发现的信息的关键。正是这些仪器所作的测量与各种目录之间的联系以及科学结果将成为使命的科学遗产。处理任务是巨大的。盖亚是一个极端的使命，这反映在所需的数据简化技术的范围：从极端准确的全球天体测量到大规模测光和光谱学，所有这些都基于在不断旋转的卫星上收集的数据。数据量很大，覆盖了近2x10^12个单独的观测值，但更重要的是，在一些数据处理中几乎需要考虑整个数据量。分析系统正在被分解为若干关键领域，这些领域总的来说构成了盖亚的最终数据处理系统。我们的建议的目的是为英国的承诺盖亚是处理系统的发展需要进行所有减少的光度和大多数光谱观测。此外，这项工作将产生支持盖亚科学警报系统所需的软件系统，该系统将代表盖亚的主要早期科学数据产品。该项目将提供旨在执行各种复杂处理任务的软件组件，* 所有200个CCD记录图像凌日数据的光度数据处理所需的软件 * 处理光度数据的数据处理系统 * 光谱数据处理和校准所需的软件 * Gaia飞行中CCD校准所需的软件 * 科学警报子系统的软件盖亚数据流系统项目由来自英国的主要团队组成，他们参与了大规模计算和分析系统的交付（如Hipparcos，XMM，Planck，VISTA）。利用获得的知识，再加上使用分布式和虚拟天文台互操作性系统的进步，将确保英国对盖亚项目做出全面和具有成本效益的承诺，提供还原和分析系统，为英国和欧洲天文学界提供最高质量的科学产品。

Gaia is a European Space Agency Cornerstone mission, to be launched Q4/2011 for a five to six year lifetime. Its scientific goal is to make the largest, most precise map of our Galaxy by conducting a census of the positions and velocities of one thousand million objects in and around our Galaxy. As such it will form the basis for studies of the structure and formation history of our Galaxy, one of the four core themes of UK astronomical research: Star Formation and Development of Galaxies. As a comprehensive survey mission, Gaia is expected to become one of science's greatest discovery machines. It will monitor each of its target objects (primarily stars, asteroids, galaxies and QSOs) on average 85 times over a five-year period, precisely charting their distances, movements, and changes in brightness. It is expected to discover hundreds of thousands of new celestial objects, such as extra-solar planets and failed stars called brown dwarfs. Within our own Solar System for example, Gaia is expected to identify tens of thousands of hitherto unknown asteroids. Expected discoveries also include the detection and characterisation of tens of thousands of extra-solar planetary systems. The survey will cover about 10 million galaxies and 500 000 distant quasars. It will further provide stringent new tests of general relativity. The Gaia data processing is the key in turning data from the satellite into information which astronomers can then analyse to make new discoveries. It is the link between measurements made by the instruments and the various catalogues with scientific results that will be the science legacy of the mission. The processing task is immense. Gaia is a mission of extremes, which reflects in the range of data reduction techniques required: from extreme-accuracy global astrometry to large scale photometry and spectroscopy, all based on data gathered in a constantly spinning satellite. The volume of data is large, covering nearly 2x10^12 individual observations, but more importantly, nearly the entire volume of data needs to be considered in some of the data processing. The analysis system is being decomposed into a number of key areas, which in sum form the final data processing system for Gaia. Our proposal's aims for the UK's commitment to Gaia is the development of the processing systems required to carry out all reductions of the photometric and most of the spectroscopic observations. Additionally, this work will generate the software systems required to support the Gaia Science Alerts system, which will represent the main early science data products from Gaia. The project will deliver software components designed to perform a wide range of complex processing tasks, * the software required for the the photometric data processing for all 200 CCDs recording image transit data * the data handling system to process the photometric data * the software required for the spectroscopic data processing and calibrations * the software for the Gaia in-flight CCD calibrations * the software for the science alerts sub system The Gaia Data Flow System project consists of key teams from the UK who have been involved in the delivery of large scale computing and analysis systems (such as that for Hipparcos, XMM, Planck, VISTA). Leveraging the knowledge there gained, coupled with use of advances in distributed and virtual observatory interoperability systems will ensure that the UK makes a full and cost effective commitment to the Gaia project, delivering a reduction and analysis system to provide the highest quality science products for eventual exploitation by the UK and European astronomical communities.