The Physics and evolution of galaxies in the epoch of re-ionisation

天体物理学中最令人兴奋的开放问题之一是了解最早的星系、恒星和黑洞的性质和演化，以及它们如何改变整个宇宙并结束黑暗时代。这个博士项目将允许学生进行和探索对非常遥远的星系（莱曼α发射体）的最大调查，并将它们推到宇宙只有700迈或更少的最高回顾时间。该学生将减少、分析和探索最近在智利的甚大望远镜上完成的（100%）Y-NBS调查（PI: Sobral）在COSMOS领域的近红外光度数据，该调查在极好的观测条件下分配了50个小时。Y-NBS调查是迄今为止对遥远明亮的莱曼α源进行的最广泛的调查，甚至比CR7星系更遥远（Sobral et al. 2015），学生预计将发现多达20个新的明亮的遥远星系，以及1000个其他低红移星暴星系和AGN。该学生还将探索我们最先进的数据集，这些数据集刚刚通过哈勃太空望远镜、ALMA和智利VLT上的其他仪器获得，将新发现的星系置于更广泛的背景下，并测试最先进的模型。该项目的第二部分将包括获取和探索后续观测，包括利用拉帕尔马的GTC（正在进行的项目）在各种波长下进行光谱分析，以研究第一批星系的物理特性。这将涉及与光电离和辐射转移模型的密切联系，并将提供一些早期星系的金属丰度、电离参数和其他特性的第一次测量。这些结果将提供重要的新信息，以改善我们目前对再电离时代的有限理解，以及遥远的明亮星系在这一过程中可能发挥的关键作用。

One of the most exciting open problems in Astrophysics is understanding the nature and evolution of the very first galaxies, stars and black holes, but also how they changed the Universe as a whole and ended the dark ages. This PhD project will allow the student to conduct and explore the largest surveys for very distant galaxies (Lyman-alpha emitters) and push them to the highest look back times when the Universe was only 700 Myrs or less. The student will reduce, analyse and explore near-infrared photometric data in the COSMOS field from the recently concluded (100%) Y-NBS survey (PI: Sobral) on the Very Large Telescope in Chile, which had an allocation of 50 hours in excellent observing conditions. The Y-NBS survey is the widest ever conducted for distant bright Lyman-alpha sources, even more distant than the CR7 galaxy (Sobral et al. 2015) and the student is expected to find up to 20 new bright distant galaxies, along with 1000s of other lower redshift starburst galaxies and AGN. The student will also explore our state-of-the-art datasets that have just been obtained with the Hubble Space Telescope, ALMA and with other instruments on the VLT in Chile, to place the newly discovered galaxies into a wider context and test state-of-the-art models. The second part of the project will involve obtaining and exploring follow-up observations, including spectroscopy at a variety of wavelengths with the GTC (on-going program) in La Palma, in order to investigate the physics of the first galaxies. This will involve a close link with photo-ionisation and radiative transfer models and will provide some of the first measurements of the metallicity, ionisation parameters and other properties of early galaxies. The results will provide crucial new information to improve our currently limited understanding of the re-ionisation epoch and how distant bright galaxies may have played a crucial role in such process.