The role of galaxy-galaxy interactions in Galaxy evolution

附近的宇宙包含了星系相互作用的惊人例子。这一过程会对一个或两个星系造成引力破坏，并可能导致合并。与此同时，这些近距离的碰撞既可以触发新一代恒星的形成，也可以(后来)在这些星系中熄灭恒星的形成。近年来，对相互作用星系的研究极大地提高了我们对这些过程的理解，尽管仍有许多需要了解。一个关键的挑战是将这些相互作用的星系的观测与更典型的(孤立的)星系联系起来，这些星系可能经历了相对较新的相互作用，深刻地改变了它们的进化史。拟议的研究计划将建立在我们在这一领域的最新贡献的基础上，并将采用我们为此目的收集的一套非凡的数据和环境分类。我们已经使用这个数据库识别了大量紧密配对和致密群的星系，这些星系提供了理想但独特的环境，在其中可以探测正在进行的、最近的和即将发生的相互作用。我们将通过测量成对星系和致密星系群的广泛性质，通过将这些性质与定义明确的对照样本中的星系进行比较，通过将紧密星系对与宽星系对联系起来，以及通过将致密星系与其周围的星系联系起来，来实现我们的科学目标。有了大小-光度关系、质量-金属度关系、颜色-颜色图和恒星形成历史等指标，我们将极大地提高我们对相互作用在星系演化中的作用的理解。我们现有的星系对和致密星系群的样本在星系的数量、测量的指数的质量和广度、复杂控制样本的使用以及将相互作用的星系与目前没有相互作用的星系直接联系起来的能力方面是无与伦比的。此外，我们拥有在未来多年开发这些资源的专业知识，并继续让博士后、研究生和本科生参与这一令人兴奋的合作努力。

The nearby universe contains striking examples of galaxies which are interacting with one another. This process gravitationally disrupts one or both galaxies, and may result in a merger. At the same time, these close encounters can both trigger the formation of new generations of stars and (later) quench star formation in these galaxies. The study of interacting galaxies has greatly improved our understanding of these processes in recent years, though much remains to be learned. A crucial challenge is to relate the observations of these interacting galaxies to more typical (isolated) galaxies, which may nevertheless have undergone relatively recent interactions that have profoundly altered their evolutionary histories. The proposed research program will build on our recent contributions in this field, and will employ an extraordinary set of data and environmental classifications that we have assembled for this purpose. We have used this database to identify large numbers of galaxies in close pairs and compact groups, which provide ideal but distinct environments within which to detect ongoing, recent and imminent interactions. We will address our science goals by measuring a wide range of properties for galaxies in pairs and compact groups, by comparing these properties to galaxies in well defined control samples, by relating close pairs to wide pairs, and by relating compact group galaxies to those in their surroundings. With metrics such as the size-luminosity relation, the mass-metallicity relation, the colour-colour diagram, and star formation histories, we are poised to greatly improve our understanding of the role of interactions in galaxy evolution. Our existing samples of galaxy pairs and compact groups are unparalleled in terms of the number of galaxies, the quality and breadth of indices measured, the use of sophisticated control samples, and the ability to directly relate interacting galaxies to those which are not currently undergoing interactions. Moreover, we have the expertise in place to exploit these resources for many years to come, and to continue to involve postdocs, graduate students, and undergraduate students in this exciting collaborative endeavour.