The archaeology of galaxies in the local group

本星系群的考古学

• 批准号: 6379-2011
• 负责人: Richer, Harvey
• 金额: $ 2.7万
• 依托单位: University of British Columbia
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2015
• 资助国家: 加拿大
• 起止时间: 2015-01-01 至 2016-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=568463
• 关键词: archaeology; galaxies; local; group

Over the past decade I ( and my research team) have been major users of the Hubble Space Telescope. We have been extremely successful in obtaining very large amounts of time (in open competition) to survey a number of ancient star clusters in our Galaxy. The main focus of the research is to determine the ages of these systems and then use that information to glean clues as to when and how our Milky Way Galaxy was formed. We have developed a new age-dating technique that involves measuring precisely the cooling rate of "dead" stars and using this as a clock. Thus far we have explored two clusters in the halo of our Galaxy and have determined that both are about the same age and very old (12 billion years). Since we are quite sure that the Universe itself is only 13.7 billion years old, we now know that our Galaxy (and likely most others) formed rather soon after the Big Bang. We have also applied our chronometer to the disk of our Galaxy which contains its magnificent spiral arms. Here we learned that this Galactic component is significantly younger - by about 4 billion years. Currently we are in the process of obtaining a new set of Hubble data on a star cluster that contains stars similar to those in the central bulge of our Galaxy. An age for this system will provide evidence on whether our Galaxy formed inside out (bulge is older) or from the outside in (bulge is younger). In addition to this stellar chronology we are pursuing a large number of other research programs with these and other data. We are exploring for planets in these clusters by searching for planetary transits across their parent stars and examining whether normal stars have excess infrared light which could indicate a cool planet or planetary disk. We have been observing a number of old star clusters for almost a decade now and the data are precise enough that we can use their positions over a period of time to resolve the INTERNAL motions within the cluster. This allows us to examine in exquisite detail the dynamics of the stars and this is revealing new and interesting phenomena, such as stars given a "kick" when they die, or evidence for a central black hole.

在过去的十年中，我（和我的研究团队）一直是哈勃太空望远镜的主要用户。我们在获得非常大量的时间（在公开竞争中）来调查了我们银河系中的许多古代恒星群。该研究的主要重点是确定这些系统的年龄，然后使用这些信息来收集我们的银河系何时以及如何形成银河系的线索。我们已经开发了一种新的年龄约会技术，涉及精确测量“死”恒星的冷却速率并将其用作时钟。到目前为止，我们已经在我们的银河系光环中探索了两个簇，并确定这两者都是相同的年龄和非常老的（120亿年）。由于我们非常确定宇宙本身只有137亿年的历史，因此我们现在知道我们的银河系（甚至大多数其他）在大爆炸之后很快就形成了。我们还将计时台应用于包含其宏伟螺旋臂的星系磁盘。在这里，我们了解到，这种银河系成分显着年轻 - 大约40亿年。目前，我们正在在一个星团上获得一组新的哈勃数据，该星团包含类似于我们银河系中央凸起的恒星。该系统的年龄将提供证据表明我们的银河系是内而外的（凸起年龄较大）还是从外部形成（Bulge还年轻）。 除了这一出色的年表外，我们还使用这些数据和其他数据探讨了许多其他研究计划。我们正在通过在其母星之间寻找行星跨的行星横向来探索行星，并检查普通恒星是否具有过量的红外光，这可能表明凉爽的行星或行星盘。我们已经近十年来观察了许多旧星团，并且数据已经足够精确，可以在一段时间内使用它们的位置来解决集群中的内部动作。这使我们能够详细检查恒星的动力学，这揭示了新有趣的现象，例如恒星死后给出了“踢”，或者证明了中央黑洞的证据。