Linking galaxies with their dark matter halos

我们知道星系生活在扩展的暗物质晕中，但这些晕的大小和形状受到很大的限制。暗物质不发光，这使得研究它的性质特别困难。然而，暗物质的数量和分布可以通过使用引力透镜的引力影响来推断。将观测到的星系与它们所处的晕联系起来，可以帮助我们约束星系形成的不同方面，例如星星形成的效率。这一提议侧重于测量两种不同质量尺度下的引力透镜，从而测量暗物质的性质。第一项研究涉及确定星系大小的物体的暗物质特性，并将暗物质特性与观察到的星系的发光特性相关联。第二项研究与星系群有关。星系群是由引力束缚的星系组成的小集合。本星系中的大多数星系都生活在星系群中，但与星系团和单个星系相比，它们的性质相对知之甚少，因为它们很难在天空中识别。我建议使用地面和空间光学成像研究这些系统，结合不同波长的互补数据，以便更好地了解星系和星系群的黑暗和明亮成分之间的关系。

We know that galaxies live in extended dark matter halos, but the size and shape of these halos are poorly constrained. Dark matter does not emit light which makes studying its properties particularly difficult. However, the amount and distribution of dark matter can be inferred by its gravitational influence using gravitational lensing. Linking observed galaxies to the halos in which they live can help us to constrain different aspects of galaxy formation, for example the efficiency of star formation.This proposal focusses on measuring the gravitational lensing, hence dark matter properties, at two different mass scales. The first study concerns determining the dark matter properties of galaxy-sized objects, and correlating the dark matter properties with the observed, luminous properties of the galaxies. The second study is related to galaxy groups. Galaxy groups are small collections of galaxies which are gravitationally bound. Most galaxies in the local universe live in galaxy groups, but their properties are relatively poorly understood compared to galaxy clusters and individual galaxies, because they are difficult to identify on the sky. I propose to study these systems using ground- and space-based optical imaging, combined with complementary data at different wavelengths in order to better understand the relationship between the dark and luminous components of galaxies and galaxy groups.