Unveiling the role of environment on the growth of galaxies and dark-matter halos

星系与周围气体有着复杂的关系。宇宙网状细丝对光晕和星系的生长起着特别重要的作用：模拟表明，宇宙中约40%的暗物质存在于细丝中，它们充当着将暗物质和中性冷气体输送到光晕和星系中的管道。中性冷气体一旦吸积到星系上，几乎总是会形成恒星，在这一点上，它很容易通过星光被探测到。然而，尽管我们是星系形成和成长的关键参与者，但在宇宙网到达星系附近之前，我们对它的气体成分知之甚少。在这个项目中，你将把遥远类星体光谱中的过剩吸收与通过星系位置探测到的灯丝相互关联，以了解宇宙网中的气体含量，远离暗物质晕的影响。你将使用EBoss和DESI数据，它们一起提供穿透低红移宇宙网的最密集的视线样本。你的观测工作将得到宇宙流体动力学模拟工作的补充。

Galaxies have a complex relationship with surrounding gas. Cosmic-web filaments take on especially important roles for halo and galaxy growth: simulations indicate that around 40 percent of the Dark Matter in the Universe is found within filaments, and they act as conduits that feed Dark Matter and neutral, cold gas into halos and galaxies. The neutral cold gas, once accreted onto a galaxy, will almost always form stars, at which point it becomes easily detectable via starlight. However, although a key player in the formation and growth of galaxies, we know astoundingly little about the gas component of the cosmic web, before it reaches the vicinity of a galaxy.In this project, you will cross-correlate excess absorption in the spectra of distant quasars with filaments detected via the positions of galaxies, to understand the gas content of the cosmic web, far from the influence of dark matter halos. You will work with eBOSS and DESI data, which together provide the densest sample of lines of sight that pierce the low-redshift cosmic web. Your observational work will be complemented by work in cosmological hydrodynamical simulations