PATT travel support for Bristol Astrophysics and Planetary Studies

布里斯托天体物理学和行星物理学小组正在进行的项目需要使用世界上最大的望远镜进行仔细的观测。该提案要求为这些望远镜的旅行提供两年的资金，以便对无法远程运行的项目进行观测。在对微波背景辐射（宇宙大爆炸遗留下来的辐射）的研究中，重要的是要从前景辐射源中去除污染，这些污染会混淆我们对背景本身的测量。清除这种污染需要使用大型射电望远镜对目标场的射电环境进行灵敏的观测。我们正在寻找的许多效应都与星系团中的气体在背景辐射上投下的“阴影”有关。我们还需要用光学和红外望远镜来研究星系团，测量星系团的质量，从而深入了解星系团在宇宙历史上是如何形成和变化的。其中一些污染射电源位于星系团内，而这些“活跃星系”的核心处有超大质量黑洞，这是我们研究的另一个主题。我们主要使用轨道x射线望远镜来研究这些物体的物理性质，但无线电、红外和光学波段的成像也是必不可少的。这里我们再次使用大型地面望远镜，特别是美国的JVLA，澳大利亚的ATCA，以及智利的ESO大型望远镜。这项工作的一个主要目的是了解活跃的星系如何将能量泵入宇宙中的气体中，帮助保持星系之间的气体温度，从而成为x射线的强大来源。这些活跃星系的小规模模型可以在我们自己的星系中找到，在质量是太阳质量几倍的黑洞系统中。研究这些星系使用的技术与研究活跃星系中质量大得多的黑洞类似，但需要频繁重复地观察，以跟踪它们亮度和结构的快速变化。从这些信息中，我们可以发现物质在黑洞附近的行为。我们工作的一个统一主线是研究宇宙的结构是如何随着时间形成和变化的。我们观测的很大一部分是致力于寻找和描述最早的星系和星系团，然后观察年轻的天体与靠近我们银河系的老天体有何不同。在这项工作中，我们再次使用了各种各样的望远镜，从智利的光学望远镜到澳大利亚和美国的射电望远镜，观察恒星和它们之间的气体。我们不仅可以比遥远的星系更详细地研究近处的星系，而且还可以观察到一些较小的天体，这些天体如果离我们较远，就会因为太暗而看不见。对我们来说，研究质量最低的星系是特别有趣的，它们是最常见的，但它们的特性却鲜为人知，而且与较大的天体大不相同。这些小星系被认为是大星系的基石。我们也研究我们自己的星系，观察被超新星或年轻恒星加热的恒星之间的气体，以及发射相干辐射（脉泽）的致密气体团，这种辐射非常明亮，随时间变化。气体运动告诉我们银河系如何从恒星中回收气体，并可用于测量银河系之间的距离。最后，我们还试图研究太阳系中行星和大型卫星的大气层。大气的形成和演变可以通过详细的光谱学来跟踪，我们使用大型地面望远镜，如美国宇航局在夏威夷莫纳克亚山的IRTF来进行。

The Bristol Astrophysics and Planetary Physics groups work on programmes that require careful observations to be made using the world's largest telescopes. This proposal requests two years of funding for travel to those telescopes, to allow observing on projects that cannot be run remotely.In studies of the microwave background radiation, the left-over radiation from the Big Bang, it is important to remove contamination from foreground sources of emission that confuse our measurements of the background itself. Removal of this contamination requires sensitive observations of the radio environments of our target fields using large radio telescopes. Many of the effects we are looking for relate to "shadows" cast on the background radiation by the gas in clusters of galaxies. We also need to study clusters with optical and infra-red telescopes, to measure cluster masses, and so gain insights into how clusters form and change over the history of the Universe.Some of these contaminating radio sources lie within the clusters, and these "active galaxies" which host super-massive black holes in their nuclei, are another subject of our research. We study the physics of these objects mostly using orbiting X-ray telescopes, but imaging at radio, infra-red, and optical bands is also essential. Here again we use large ground-based telescopes, particularly the JVLA in the USA, the ATCA in Australia, and ESO's large telescopes in Chile. A major aim of this work is to understand how active galaxies pump energy into gas in the Universe, helping to keep the gas between the galaxies hot, and so a powerful source of X-rays.Small-scale models of these active galaxies can be found in our own Galaxy, in black hole systems with masses a few times the mass of the Sun. Work on these systems uses similar techniques as work on the far heavier black holes in active galaxies, but with the need to observe frequently and repeatedly, to follow their rapid changes in brightness and structure. From such information we can discover how matter behaves near black holes.A unifying thread of our work is investigating how structure in the Universe forms and changes with time. A large fraction of our observing is dedicated to finding and characterising the earliest galaxies and clusters, and then seeing how young objects differ from their older counterparts that lie close to our Galaxy. Again we use a wide range of telescope for this work, from optical telescopes in Chile to radio telescopes in Australia and the USA, looking at the stars and the gas between them.Nearby galaxies can not only be studied in more detail than distant ones, but we can also look at smaller objects which would be too faint to see if they were further away. It is particularly interesting to us to investigate the lowest-mass galaxies, which are the most common, but have properties that are poorly understood and rather different from the larger objects. These small galaxies are thought to be the building blocks of larger galaxies.We also study our own Galaxy, looking at the gas between the stars which has been heated by supernovae or young stars, and at the dense lumps of gas that emit coherent (maser) radiation - which is extremely bright and variable with time. Gas motions tell us about how the Galaxy recycles gas from stars, and can be used to measure the distances across the Galaxy.Finally, we also seek to investigate the atmospheres of planets and large satellites in our own Solar System. Atmosphere formation and evolution can be followed by detailed spectroscopy, which we undertake using large ground-based telescopes such as NASA's IRTF on Mauna Kea, Hawaii.