Hertfordshire Astronomy 2018-2021

天体物理研究中心开展了从X射线到无线电波长范围的观测计划--通过计算机建模和模拟来支持这一计划。我们的研究范围从对长波长的高红移星系的观测，到对试图探测太阳系外行星的观测的新的统计分析。在这两个极端之间，我们进行了迄今为止规模最大的多波长观测，以了解银河系的特性。我们的研究利用了欧洲和国际所有主要天文观测站的观测资料，包括光学、射电和亚毫米波长的地面观测站，以及波长从远红外到X射线的空间观测站。计算机模拟让我们更好地了解在我们的观测中检测到的物理过程，我们需要应用先进的数据挖掘技术来处理我们正在生成的~TB数据集。以下是我们在这些领域的研究的简要描述。我们搜索附近的恒星以发现行星，并在应用径向速度方法方面处于世界领先地位；我们在赠款期间的重点将是类太阳附近恒星周围的行星数量。我们还发现、跟踪和模拟了温度与行星温度重叠的最冷棕矮星的性质。这些研究的目的是了解GAIA卫星探测到的棕矮星种群的多样性，并确定它们的形成模式如何与不同质量的兄弟恒星(即较重的恒星或较轻的行星)的形成模式相适应。银河系是我们的家园。它内部以气体和尘埃的形式存在的物质是形成恒星和行星系统的原材料。在恒星寿命结束时，其中一些物质仍被锁在恒星残留物中，但大部分物质在超风后期和超新星爆发时被送回。年轻时的吸积和老年时的流出之间的循环通过注入气体中的热能和机械能来丰富气体介质并控制其动力学。通过使用大面积成像测量，我们的研究着眼于银河系内的气体、尘埃和恒星是如何联系在一起的，以及恒星如何形成的细节。我们的调查跨越了光学到射电领域，追踪恒星、灭绝、分子云、它们的尘埃特性和相关的恒星形成。放眼银河系之外，有可能评估恒星如何在不同的环境中形成和演化，从小矮星系到其他星系的外部，如我们自己的星系。我们研究星系的气体含量，为恒星的形成提供材料，并将我们的发现与恒星群和整个局部星系的恒星形成区域联系起来。通过了解触发附近宇宙恒星形成和恒星演化的过程，我们可以将这种理解应用于遥远宇宙中最早的星系和第一代恒星。事实上，我们的一些工作重点是利用ALMA等尖端仪器，在亚毫米波长以极高的效率探测到高红移星系。新一代观测正在绘制最远的星系图，使我们能够研究恒星形成过程和超大质量黑洞增长的联系。我们还使用详细的射电和X射线观测，以及计算机模拟，来测量从超大质量黑洞喷出的喷流注入到遥远的星系和星系团的能量，影响恒星形成和气体性质，并在它们的进化史上发挥长期作用。这些星系中化学元素的演化，以及黑洞活动和元素丰度之间的相互作用，是这一提议的一个特别重点。

The Centre for Astrophysics Research carries out observational programmes spanning the wavelength range from X-ray to radio -- supporting this by computer modelling and simulation. Our research ranges from observations of high-redshift galaxies at long wavelengths through to novel statistical analyses of observations seeking to detect planets outside our Solar System. In between these extremes, we carry out the largest multi-wavelength surveys conducted to date to understand the properties of the Milky Way. Our research makes use of observations from all of the main European and international astronomical observatories, including ground-based observatories at optical, radio and submillimetre wavelengths, and space observatories at wavelengths ranging from the far infrared to X-rays. Computer simulations gives us a better understanding of the physical processes detected in our observations, and we need to apply advanced data-mining techniques to work with the ~terabyte datasets we are generating. Below is a brief description of our research in each of these areas.We perform searches of nearby stars to discover planets, and are world leaders in the application of radial-velocity methods for this purpose; our focus in the grant period will be the planet populations around Sun-like nearby stars. We also discover, follow up and model the properties of the coolest brown dwarfs whose temperatures overlap with those of planets. These studies aim to understand the diversity of the population of brown dwarfs detected with the Gaia satellite and to establish how their modes of formation fit in with those of their brethren of different masses, i.e. heavier (stars) or lighter (planets). The Milky Way is our home galaxy. Material within it, in the form of gas and dust, is the raw material for forming stars and planetary systems. At the end of stellar lives some of this material remains locked up in stellar remnants but much of it is returned in late superwind phases and supernova explosions. The cycle between accretion in youth and outflow in old age enriches the gaseous medium and governs its dynamics, via the thermal and mechanical energy injected into the gas. By using large area imaging surveys, our research looks at how gas, dust and stars within the Milky Way are connected, and at the details of how stars are formed. Our surveys span the optical to radio domains, tracing stars, extinction, molecular clouds, their dust properties and associated star formation.Looking beyond the Milky Way, it is possible to appraise how stars form and evolve in different environments, from small dwarf galaxies to the outer parts of other galaxies like our own. We study the gas content of galaxies, providing the material for star formation, and link what we find to stellar populations and to star forming regions in the full range of local galaxies. By understanding the processes that trigger star formation and stellar evolution in the nearby Universe, we can apply this understanding to the very earliest galaxies and the first generations of stars in the distant Universe. Indeed some of our work focuses on high-redshift galaxies detected with great efficiency at sub-millimetre wavelengths, making use of cutting-edge instruments such as ALMA.A new generation of surveys is mapping out the most distant galaxies, and allows us to investigate what links the processes of star formation and the growth of supermassive black holes. We also use detailed radio and X-ray observations, along with computer modelling, to measure the energy injected by jets ejected from supermassive black holes into distant galaxies and clusters of galaxies, affecting star formation and gas properties, and playing a long-term role in their evolutionary history. The evolution of the chemical elements in these galaxies, and the interplay between black-hole activity and elemental abundances, is a particular focus of this proposal.