Astrophysics at Southampton

理解致密天体的吸积和发射，包括高能(X和伽马射线)发射与光学和射电发射之间的关系，特别强调时间域研究，仍然是小组研究的重要部分。以前，我们的主要强项是研究太阳质量尺度的致密天体，例如X射线双星(XRBs)。在我们保持这一实力的同时，集团最近的扩张，加上员工的大量更替，使我们能够加强我们在银河系外和宇宙领域的研究，而这些领域以前我们的实力较弱。因此，总体来说，这个群体更加平衡。在最局部的尺度上，我们正在扩大我们对地球磁层的研究，以涵盖我们自己太阳系内的其他行星，特别是土星，以提高我们对磁层磁力线重新连接的理解。磁场在喷流形成中很重要，因此我们将研究恒星形成区和年轻恒星物体中喷流中的磁力线强度，以提高我们对原恒星演化的理解。在小的“致密天体”尺度上，我们正在模拟奇怪的超快X射线瞬变(SFXT)的演化，这种瞬变最初是由欧空局伽马射线/硬X射线天文台发现的，我们领导了它的发展。我们还希望了解XRBs中旋转中子星的磁吸积背后的物理机制，并对3D吸积结构进行建模。我们还希望了解XRBs中的吸积动力中子星向低吸积速率的旋转动力射电脉冲星的转变。我们将通过观测和建模来研究所有黑洞(BH)质量系统在接近最大可能(爱丁顿)吸积率时的吸积物理行为是否相同。我们正在对附近280个星系的完整样本进行深度eMerlin射电遗产调查(Lemmings)，以确定局部环境(即星系类型)或BH质量是否影响核内超大质量BH的吸积。我们还将发现不同星系类型中BH质量、射电和X射线光度之间的确切关系。对于X射线明亮的活动星系核，我们正在通过X射线能带之间时间滞后的广义相对论模型，在黑洞周围的强引力场中量化其中心X射线源和周围物质，如吸积盘的几何形状。我们还试图了解活动星系核的X射线发射与光学和无线电波段的X射线发射之间的关系。在所有尺度上观察到的致密天体的大部分行为都可以通过周围的外流来解释，这些外流改变和重新处理了核发射，产生了光学/UV发射线，并导致了不同的X射线吸收。我们正在开发一个风模型来解释AGN的这些观测结果。来自活动星系核的喷流通过能量反馈，可以严重影响周围星系和星系团的生长和外观。我们正在进行第一次调查，以确定这种相互作用实际上是如何在高红移(z&gt；1)发生的。为了提供一个我们的其他工作可以适用的宇宙学框架，我们正在通过半解析技术(包括来自活动星系核的能量输入)模拟星系的大规模演化及其分布。这些模型将与我们将从最深的eMerlin调查(Emerge)得出的AGN和SFGs的演化光度函数进行比较。在非常大的尺度上，我们正在使用超新星作为标准蜡烛来测量宇宙本身的几何形状。尽管我们的工作主要是基于观测，但现在几乎所有的情况都包含了相当一部分的理论或计算机模拟。这个模型在星系演化和类星体风的情况下是明显的，但也是非常重要的，例如在SFXTS和中子星XRBs以及AGN X射线滞后中。

Understanding accretion onto, and emission from, compact objects, including the relationship between high energy (X and Gamma-ray) emission and optical and radio emission, with particular emphasis on time domain studies, remains an important part of group research. Previously our main strengths were in the study of solar-mass scale compact objects, eg X-ray binary sources (XRBs). Whilst we retain this strength, the recent expansion of the group, coupled with considerable turnover of staff, has enabled us to enhance our research in the extragalactic and cosmological areas where previously we were less strong. Thus, overall, the group is more balanced.On the most local scales, we are expanding our studies of the earth's magnetosphere to encompass that of other planets within our own solar system, particularly Saturn, to improve our understanding of magnetospheric field line reconnection. Magnetic fields are important in jet formation so we will be investigating the magnetic field line strengths in jets in star-forming regions and young stellar objects to improve our understanding of protostellar evolution. On small 'compact object' scales we are modelling the evolution of the strange Super Fast X-ray Transients (SFXTs), originally discovered by the ESA Gamma-ray/hard X-ray observatory, INTEGRAL, whose development we led. We also wish to understand the physics behind magnetic accretion onto rotating neutron stars in XRBs and model the 3D accretion structures. We also wish to understand the transition from accretion powered neutron stars in XRBs to rotation powered radio pulsars at lower accretion rates. We will study, by observation and modelling, whether the behaviour of accretion physics at near the maximum possible (Eddington) accretion rate is the same for systems of all black hole (BH) masses.We are carrying out a deep eMERLIN radio legacy survey (LeMMINGs) of a complete sample of 280 nearby galaxies to determine whether the local environment (ie galaxy type) or BH mass affects the accretion onto the supermassive BH in the nucleus. We will also discover the exact relationship between BH mass, radio and X-ray luminosities in different galaxy types. For X-ray bright AGN we are quantifying the geometry of their central X-ray sources and surrounding material, eg accretion discs, in the strong gravitational fields around black holes by General Relativistic modelling of the time lags between X-ray energy bands. We are also trying to understand the relationship between the X-ray emission in AGN and that in the optical and radio bands.Much of the observed behaviour of compact objects on all scales may be explained by surrounding outflows which modify and reprocess the nuclear emission, producing optical/uv emission lines and resulting in variable X-ray absorption. We are developing a wind model to explain these observations for AGN. Jets from AGN, through feedback of energy, can seriously affect the growth and appearance of surrounding galaxies and clusters. We are carrying out the first survey to determine how this interaction actually occurs at high redshift (z > 1). To provide a cosmological framework into which our other work can fit, we are modelling the large scale evolution of galaxies and their distribution via semi-analytic techniques, including energy input from AGN. These models will be compared with the evolving luminosity functions of AGN and SFGs we will derive from the deepest eMERLIN survey (eMERGE). On the very largest scales we are measuring the geometry of the universe itself using Supernovae as standard candles.Although our work is mostly based on observations, almost all cases now contain a substantial fraction of theoretical or computer modelling. This modelling is obvious in the galaxy evolution and QSO wind cases but is also very important, eg, in SFXTs and neutron star XRBs and in AGN X-ray lags.