PATT travel support for Bristol Astrophysics and Planetary Studies

布里斯托尔天体物理学和行星物理学小组致力于一些项目，这些项目需要使用世界上最大的望远镜进行仔细的观测。这项提议需要两年的资金用于前往这些望远镜，以便能够对不能远程运行的项目进行观测。在对微波背景辐射的研究中，消除前景辐射源中的污染是很重要的，因为这些污染源会混淆我们对背景本身的测量。消除这种污染需要使用大型射电望远镜对我们目标领域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气体在背景辐射上投射的“阴影”有关。我们还需要用光学和红外望远镜来研究星系团，以测量星系团的质量，从而深入了解星系团在宇宙历史上是如何形成和变化的。其中一些受污染的射电源位于星系团内，而这些在其核中拥有超大质量黑洞的“活动星系”，是我们研究的另一个主题。我们主要使用轨道X射线望远镜研究这些天体的物理，但无线电、红外线和光学波段的成像也是必不可少的。这里我们再一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的大型望远镜。这项工作的一个主要目的是了解活动星系是如何将能量输送到宇宙中的气体中，帮助保持星系之间的气体热，从而成为X射线的强大来源。这些活动星系的小规模模型可以在我们自己的银河系中找到，在质量是太阳几倍的黑洞系统中。对这些系统的研究使用了与活动星系中质量大得多的黑洞类似的技术，但需要频繁和重复地观察，以跟踪它们的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线索是研究宇宙中的结构是如何形成和随时间变化的。我们观测的很大一部分致力于寻找和描述最早的星系和星系团，然后观察年轻天体与靠近银河系的较老天体的不同之处。再一次，我们使用了广泛的望远镜来进行这项工作，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。近处的星系不仅可以比远处的星系更详细地研究，而且我们还可以观察更小的物体，因为它们太暗了，看不到它们是否在更远的地方。我们特别感兴趣的是研究最低质量的星系，这是最常见的，但具有鲜为人知的性质，与较大的天体有很大的不同。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，以及发出相干(脉泽)辐射的密集气体块--这是非常明亮的，随着时间的变化。气体运动告诉我们银河系如何回收恒星的气体，并可以用来测量整个银河系的距离。最后，我们还试图调查我们太阳系中行星和大型卫星的大气层。大气的形成和演化可以通过详细的光谱来跟踪，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的IRTF进行这项工作。

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.