Research in Theoretical Astronomy 2009-2014

剑桥天文学研究所是世界领先的天文学研究机构之一。它包括19名学术人员，51名博士后研究助理和52名博士生，其中约一半从事理论天文学工作。这个补助金申请要求在IoA的主要理论滚动补助金的更新。在今后五年中，我们将对下列问题进行广泛的理论研究：（一）普朗克卫星是第三代空间卫星，专门用于测量宇宙微波背景中的温度和偏振各向异性。普朗克卫星计划于2008年底发射，距首次向欧空局提出发射计划已有15年。赠款所涉年份正好是这颗卫星科学利用的高峰期。请求PDRA提供支持，以便与共同调查员就核心科学项目开展合作。特别是，我们负责领导普朗克宇宙学参数的关键分析，并希望研究宇宙膨胀模型的约束。剑桥在三叶草极化实验中发挥了主导作用，我们希望PDRA参与该实验的科学解释。(ii)宇宙微波背景辐射为我们提供了宇宙40万年前的图像。当时，宇宙充满了氢、氦、暗物质和辐射的近乎均匀的混合物。我们将研究第一个非线性结构是如何从这种随机背景中出现的。在资助期内，研究的主要重点将是进行流体动力学模拟，包括辐射转移，以模拟星系际介质的热状态和空间扩展Lyalpha发射。我们还将扩展以前的工作，从Ly α森林的物质功率谱约束中微子质量，结合普朗克数据。(iii)大量太阳系外行星的发现引起了人们对行星形成理论工作的极大兴趣。在赠款期间，我们将利用原行星和碎片盘演变方面的专门知识开展一项研究方案。这项工作将集中在连接原行星阶段，当磁盘是气体丰富和正在进行的气态行星形成的可能地点，通过碎片盘阶段，当磁盘是气体贫乏，尘埃结构，与星子贝尔作为类地行星形成的可能地点。(iv)吸积盘存在于各种天文系统中。特别是，黑洞、中子星和白色矮星等致密物体的吸积产生的观测特征为X射线卫星和引力波探测器提供了主要的科学依据。磁场是理解吸积盘演化的核心。我们将进行磁化吸积盘的最先进的数值模拟，以了解它们在吸积盘动力学中的作用，并计算观测签名。(v)理解恒星演化对于解释所有天体物理系统至关重要，从我们银河系中的恒星到宇宙中第一个非线性结构的形成。在接下来的五年里，我们将开发出大质量恒星作为超新星和伽马射线爆发祖先的改进模型。我们还将与利弗莫尔的同事合作，开发双星系统中恒星演化的全三维数值模型。(vi)最后，我们将追求两个研究主题，以了解星系团核心的反馈过程。我们将研究“发射谱线共振体”的物理学，这仍然是不了解的，我们将使用大型数值模拟来评估重子物理学对使用星系团作为宇宙学探测器的影响（例如测试暗能量的性质）。

The Institute of Astronomy, Cambridge, is one of the worlds leading research Institutes in Astronomy. It comprises 19 academic staff, 51 postdoctoral research assistants and 52 PhD students, about half of whom work on theoretical astronomy. This grant application is asking for a renewal of the main theoretical rolling grant at the IoA. Over the next five years we will pursue a broad range of theoretical research on the following problems: (i) The Planck satellite is a third generation space satellite dedicated to measuring the temperature and polarization anisotropies in the cosmic microwave background. Planck is scheduled for launch at the end of 2008, some 15 years after it was first proposed to ESA. The years covered by the grant coincide with the peak period for the scientific exploitation of this satellite. PDRA support is requested to work with the Co-Investigators on core science projects. In particular, we are responsible for leading the key analysis of cosmological parameters from Planck and wish to investigate constraints on models of cosmic inflation. Cambridge has a leading role in the Clover polarization experiment and we wish to involve PDRAs in the scientific interpretation of that experiment. (ii) The cosmic microwave background radiation provides us with a picture of the Universe when it was 400,000 years old. At that time, the Universe was filled with a near uniform mixture of hydrogen , helium, dark matter and radiation. We will investigate how the first non-linear structures emerged from this stochastic background. Over the grant period the main emphasis of the research will be to perform hydrodynamic simulations including radiative transfer to model the thermal state of the intergalactic medium and spatially extended Lyalpha emission. We will also extend previous work on the matter power spectrum from the Ly alpha forest to constrain neutrino masses, in combination with data from Planck. (iii) The discovery of large numbers of extrasolar planets has led to enormous interest in theoretical work on the formation of planets. Over the grant period we will pursue a research programme building on expertise in protoplanetary and debris disk evolution. The work will be centred on linking the protoplanetary phase, when discs were gas rich and possible sites of ongoing gaseous planet formation, through to the debris disc phase, when discs were gas poor, dusty structures, with planetesimal bels as possible sites for terrestrial planet formation. (iv) Accretion discs are present in a wide variety of astronomical systems . In particular, accretion onto compact objects such as black holes, neutron stars and white dwarfs produce observational signatures that provide the main scientific justification for X-ray satellites and gravitational wave detectors. Magnetic fields are central to understanding the evolution of accretion discs. We will perform state-of-the-art numerical simulations of magnetised accretion discs to understand their role in accretion disc dynamics and to compute observational signatures. (v) Understanding stellar evolution is essential for the interpretation of all astrophysical systems, from stars in our own Galaxy to the formation of the first non-linear structures in the Universe. Over the next five years we will develop improved models of massive stars as the progenitors of supernovae and gamma-ray bursts. We will also develop fully three-dimensional numerical models of stellar evolution in binary systems, in collaboration with colleagues at Livermore. (vi) Finally, we will pursue two research themes to understand feedback processes in the cores of clusters of galaxies. We will investigate the physics of `emission line filaments', which are still not understood and we will use large numerical simulations to assess the impact of baryonic physics on the use of clusters as cosmological probes (e.g. testing the nature of dark energy.