Hertfordshire Astronomy 2018-2021

天体物理研究中心开展的观测项目涵盖了从x射线到无线电的波长范围，并通过计算机建模和模拟来支持这一点。我们的研究范围从对长波高红移星系的观测，到对观测结果进行新颖的统计分析，以寻找太阳系外的行星。在这两个极端之间，我们进行了迄今为止最大的多波长调查，以了解银河系的特性。我们的研究利用了所有主要的欧洲和国际天文观测站的观测结果，包括光学、无线电和亚毫米波长的地面观测站，以及从远红外到x射线波长的太空观测站。计算机模拟使我们更好地理解了在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。下面是我们在这些领域的研究的简要描述。我们对附近的恒星进行搜索以发现行星，在应用径向速度法这一目的方面处于世界领先地位；我们在拨款期间的重点将是在类太阳恒星附近的行星数量。我们还发现，跟踪和模拟温度与行星温度重叠的最冷的褐矮星的特性。这些研究旨在了解盖亚卫星探测到的褐矮星种群的多样性，并确定它们的形成模式如何与不同质量的兄弟（即较重的（恒星）或较轻的（行星））相适应。银河系是我们的家星系。其中以气体和尘埃形式存在的物质是形成恒星和行星系统的原材料。在恒星生命结束时，这些物质中的一些仍然被锁在恒星残骸中，但其中大部分在后期的超风阶段和超新星爆炸中返回。青年时期的吸积和老年时期的流出之间的循环丰富了气体介质，并通过注入气体的热能和机械能来控制其动力学。通过使用大面积成像调查，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。我们的调查跨越光学到无线电领域，追踪恒星，消光，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，我们有可能评估恒星是如何在不同的环境中形成和演化的，从小型矮星系到像我们这样的其他星系的外部。我们研究星系的气体含量，为恒星形成提供材料，并将我们的发现与恒星种群和本地星系的恒星形成区域联系起来。通过了解附近宇宙中触发恒星形成和恒星演化的过程，我们可以将这种理解应用于最早的星系和遥远宇宙中第一代恒星。事实上，我们的一些工作集中在高红移星系上，利用像ALMA这样的尖端仪器，在亚毫米波长下高效地探测到。新一代的调查正在绘制出最遥远的星系，并使我们能够研究恒星形成过程和超大质量黑洞的增长之间的联系。我们还使用详细的无线电和x射线观测，以及计算机建模，来测量超大质量黑洞喷射到遥远星系和星系团的能量，影响恒星形成和气体特性，并在它们的进化史中发挥长期作用。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，是这个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.