Support for an observing programme at the University of Hertfordshire

赫特福德郡大学的天体物理研究中心(CAR)有非常广泛的观测计划。一些例子是：CAR天文学家使用各种技术，研究宇宙各个时期的星系和结构的形成和演化。我们利用恒星形成的大规模爆发来研究星系形成和演化的早期时期。它们在光学甚至近红外波长下被高度遮挡，因此使用JCMT上的Scuba(Scuba-2)等仪器，通过热尘埃发出的经过再处理的亚毫米辐射最好地观察到它们。通过以亚毫米波长的已知高红移活动星系核(AGN)的场为目标，可以探索早期宇宙中过密集的区域。这样的活动星系核是当时存在的最大质量的天体之一，应该是暗物质分布的罕见高密度峰值的信号。汽车天文学家在国际事物(HI附近星系调查)和小事物(追踪光度极值的局部不规则星)的合作中发挥着关键作用。这两个都是NRAO超大型阵列的大型项目，对附近星系进行21厘米的HI观测。目标是研究与星系形态、恒星形成和哈勃星系序列中的质量分布有关的关键特征。在一个完全不同的大小尺度上，CAR天文学家解决了宇宙物体的形成和演化的关键问题，这些物体的尺度范围从大质量恒星到棕矮星(质量低于维持氢燃烧所需的质量的亚恒星物体)，以及系外行星。我们研究了包括银河系在内的局部群星系的恒星群，以追踪年龄和金属丰度梯度以及它们的结构，使用不同演化阶段的恒星。我们还通过记录极老恒星的高分辨率光谱来研究银河系化学演化的最早阶段，这保存了银河系最早纪元的化石记录。由此，我们可以了解大爆炸和新形成的星系在其第一批恒星出现时的条件。低质量到中等质量的恒星(0.8到8个太阳质量)以冷却白矮星的形式结束它们的生命。这是银河系中的大多数恒星都将经历的一次转变，可能包括太阳在内，恒星生命的这些结束阶段的特点是巨大的质量损失，这是星际介质中尘埃和化学浓缩物质的主要来源。这是使用包括成像偏振测量在内的各种技术来研究的。了解恒星是如何形成的仍然是现代天体物理学研究的主要目标之一，因为它支持对一系列现象的研究，例如星系(包括我们自己的星系)的形成和演化，宇宙中第一批恒星的形成，一直到我们自己的太阳系和其他类似的星系，也许还有生命本身。我们现在主要集中在大质量恒星上，因为它们是我们银河系和其他星系中的一股强大力量，在爆炸为超新星之前，它们可以破坏巨大的分子云，引发新一代恒星的形成。一旦大质量恒星形成，它们就高度可见，但它们的早期阶段仍然笼罩在秘密之中，因为它们的发源地隐藏在黑暗分子云最密集的区域的深处，需要无线电/亚毫米观测来探测这些模糊的区域。我们参与了一系列探测和描述太阳系外行星和棕矮星的计划，我们是世界上少数几个发现附近太阳系外行星(超过50颗)的小组之一。我们正在开创一系列新的太阳系外行星项目，包括凌日低质量恒星，目的是探测其母恒星宜居带内的太阳系外“地球”。

The Centre for Astrophysics Research (CAR) at the University of Hertfordshire has a very wide range of observational programmes. Some examples are: Using a variety of techniques, CAR astronomers study galaxy and structure formation and evolution, over all cosmic epochs. We use massive bursts of star formation to investigate early epochs of galaxy formation and evolution. These are highly obscured at optical and even near-infrared wavelengths, and hence best observed through the reprocessed submillimetre emission from warm dust, using instruments such as SCUBA (SCUBA-2) on the JCMT. Over-dense regions of the early universe can be explored by targeting the fields of known high-redshift active galactic nuclei (AGN) at submillimetre wavelengths. Such AGN are amongst the most massive objects in existence at their epoch and should signpost rare high-density peaks of the dark matter distribution. CAR astronomers play a key role in the international THINGS (The HI Nearby Galaxy Survey) and LITTLE THINGS (Local Irregulars That Trace Luminosity Extremes) collaboration. Both are large programmes at the NRAO Very Large Array, to perform 21-cm HI observations of nearby galaxies. The goal is to investigate key characteristics related to galaxy morphology, star formation and mass distribution across the Hubble sequence of galaxies. On an overall very different size scale, CAR astronomers address the key issues of the formation and evolution of cosmic objects that range over scales from high-mass stars to brown dwarfs (sub-stellar objects with a mass below that necessary to maintain hydrogen-burning), and exoplanets. We study the stellar population of Local Group galaxies, including the Milky Way, to trace age and metallicity gradients as well as their structure using stars in different evolutionary stages. We also study the earliest phases of the chemical evolution of the Milky Way by recording the high-resolution spectra of extremely old stars which preserve the fossil record of the Galaxy's earliest epochs. From this we can learn about the Big Bang and the conditions in the newly forming Galaxy when its first stars were emerging. Low to intermediate mass stars (0.8 to 8 solar masses) end their days as cooling white dwarfs. This is a transition that will be undergone by the majority of stars in the Galaxy, probably including the Sun, and these end phases of a star's life are characterized by huge mass loss, which is the major source of dust and chemically enriched material in the interstellar medium. This is studied using a variety of techniques including imaging polarimetry. Understanding how stars form remains one of the major goals of modern astrophysics research, as it underpins the study of a range of phenomena, such as the formation and evolution of galaxies (including our own), the formation of the first stars in the Universe through to our own Solar System and others like it, and perhaps of life itself. We now largely concentrate on massive stars as these are a powerful force in our Galaxy and others, acting to disrupt giant molecular clouds and trigger new generations of star formation before exploding as supernovae. Once massive stars have formed they are highly visible but their earliest stages are still shrouded in secrecy as their birthplaces are hidden deep within the densest regions of dark molecular clouds and radio/submm observations are needed to probe these obscured regions. We are involved in a wide variety of programmes to detect and characterise extrasolar planets and brown dwarfs, and we are one of just a few groups worldwide to discover nearby extrasolar planets (over 50). We are pioneering a number of new extrasolar planet projects , including transits of low mass stars, with the aim of detecting extrasolar 'Earths' within the habitable zones of their parent stars.