Star-forming Galaxies in the Distant Universe with Herschel and LOFAR

天体物理学的一个关键目标是了解星系的形成和演化。今天的星系已经通过恒星的形成和合并建立了它们的恒星种群。因此，直接测量高红移星系中的恒星形成率是推进我们对这些过程的理论理解的关键组成部分。然而，在高红移时，至少一半的恒星形成活动被尘埃掩盖，只能通过远红外(FIR)和射电波长的观测来探测。这样的观测对于星系演化的情景尤为关键。近年来，远红外线仪器scuba的著名发现(以及随后的射电观测)证明了这一点，这些星系具有非常高的恒星形成率，这是目前的模型极难解释的。LOFAR和ESA的Herschel任务是为研究这些红移较高的模糊恒星形成星系而设计的，这两个设施正在开展引人注目的调查项目。Scuba调查的开创性结果是基于面积为0.25平方英尺的几个星系。学位。相比之下，赫歇尔星系外遗产项目整理了超过1300度的数据，探测到了100K的远红外星系，而LOFAR的深度探测将涵盖类似的区域。这些区域是覆盖所有星系环境(从星团到空洞)的必要区域，也是严格检验星系形成理论的具有统计学意义的样本。这两次探测在天空的同一区域密切协调，因为两次探测都掩盖了恒星的形成，但机制不同。在苏塞克斯，我们正在开发新的贝叶斯工具(XID+)，以对星系调查数据进行经验建模。此外，还将有一个新的调查项目LOFAR Weave，该项目使用WHT来获得LOFAR源的红移。学员资格的目的将是：(A)为最极端的亚毫米源提供LOFAR的识别，这些源是打破最高红移和高恒星形成率星系理论的候选者；(B)利用XID+测试用于众所周知的FIR/射电关联的演化；(C)扩展XID+以利用LOFAR WAVE的光谱数据来确定最终的恒星形成率定标关系，并为未来如4MOST的更大的光谱测量做好准备。

A key goal in astrophysics is to understand galaxy formation and evolution. Galaxies today have built up their stellar populations by star-formation and merging. Therefore direct measurements of the star-formation rates in galaxies at high redshift are a key component in advancing our theoretical understanding of those processes. However, at high redshift at least half of the star formation activity is obscured by dust and can only be probed by observations at far infrared (FIR) and radio wavelengths. Such observations are particularly critical for galaxy evolution scenarios. This was notably demonstrated in recent years by the famous discovery by the far infrared instrument SCUBA (and subsequent radio observations) of numerous galaxies with very high star-formation rates that are extremely hard to explain by current models. LOFAR and ESA's Herschel mission were designed for studying these obscured star-forming galaxies at high redshift and high profile survey projects are being carried out by both facilities. The pioneering results from surveys with SCUBA are based on few galaxies over areas of 0.25 sq. degrees. In contrast the Herschel Extragalactic Legacy Project collates date over 1300 deg^2 degrees detecting 100k far infrared galaxies and the LOFAR Deep survey will cover similar areas. These areas are necessary to cover the full range of galaxy environments (from clusters to voids) and to provide statistically significant samples to rigorously test galaxy formation theories. These two surveys are closely coordinated in the same regions of the sky since both probe obscured star-formation but through different mechanisms. At Sussex we are developing new Bayesian tools (XID+) to empirically model galaxy survey data. In addition there will be a new survey project LOFAR WEAVE which uses WHT to get redshifts for LOFAR sources. The objective of the studentship will be (a) to provide LOFAR identifications for the most extreme sub-mm sources, which are candidates for the theory-busting highest redshift and high star-formation rate galaxies (b) to exploit XID+ test for evolution in the well-known FIR/radio correlation (c) to extend XID+ to work with the spectral data from LOFAR WEAVE and determine definitive star formation rate calibration relations and prepare for larger spectroscopic surveys in the future such as 4MOST.