High Energy Astrophysics at Southampton

南安普顿高能天体物理学

• 批准号: ST/J001600/1
• 负责人: Ian McHardy
• 金额: $ 113.63万
• 依托单位: University of Southampton
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2012
• 资助国家: 英国
• 起止时间: 2012 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=ST%2FJ001600%2F1
• 关键词: Energy; Astrophysics; Southampton

Our research concerns compact objects, ie white dwarfs, neutron stars and black holes (BHs), both stellar sized and supermassive (SMBHs). We aim to understand how they evolve and how they produce radiation.X-ray binaries (XRBs), which contain bright accretion discs around BHs and neutron stars, allow detailed examination of how these discs vary. As they vary quickly, many measurements of variability can be made, allowing us to see how variability at different frequencies is tied together. Using these measurements, we can test fundamental ideas about how and why matter falls in through discs. Using variations in the infrared emission, we can look at variations in the jet, and learn how the discs feed the relativistic jets we see in XRBs.Strong radio emission from the jet often accompanies accretion, particularly in the `hard' state of XRBs. We will investigate how radio emission, as seen in new observatories such as LOFAR and eMERLIN, is related to X-ray emission, as a means of studying the accretion/outflow connection. We will study why, in hard state sources, the potential accretion energy is sometimes converted efficiently into radiation, and sometimes not. We will measure black hole spin, which is important in determining how much of the accretion energy can be liberated as radiation.Studying massive stars in binary systems and their evolution gives important insight into recent star formation in the Milky Way and nearby galaxies. The evolved stellar population of the SMC points to recent turbulent interactions with its companion galaxy, producing a very active period of star formation. Many of these massive stars have evolved through a supernova phase, producing a large population of neutron stars. Studies of this population are revealing crucial insight into the nature of stellar evolution.Accreting white dwarfs (AWD) are astrophysically important. They include Type Ia Supernova progenitors, and the processes that drive their evolution are relevant in many other settings. Here we will extend our leading work on the evolution of AWDs and related systems. We will implement a new evolution track for AWDs, directly detect the first sub-stellar secondary, determine the space density of AWD, carry out a search for "dead" AWDs and confirm the first double-degenerate SN Ia progenitor.We will study the relationship between stellar-mass BHs and SMBHs (ie AGN), asking whether properties such as variability timescales, or time lags between energy bands, scale only with mass, or also with accretion rate. We will see whether AGN which have jets vary differently to those which don't, and if X-rays and Gamma-rays vary differently. We will observe how optical and radio variations are related to X-ray variations in AGN with and without jets. Thus, in different AGN types, we will determine how and where the emissions in different wavebands are produced and why they vary.The large-scale jets from SMBHs can extend for distances of millions of light years, transporting energy not only to their host galaxy but also to the surrounding group or cluster of galaxies. This energy input plays an important role in how galaxies and clusters form and evolve. We will use new radio facilities, e.g. LOFAR and e-MERLIN, to measure the energetic impact of, and investigate the life cycles of, different populations of radio-loud AGN, to understand their role ingalaxy evolution.SMBHs exist in the nuclei of possibly all galaxies but are often undetectable due to very low accretion rates. To study these low luminosity AGN, which dominate the local universe, we are making a sensitive radio and X-ray survey of the best-selected sample of nearby galaxies, the Palomar sample, to find faint AGN and determine which host galaxy properties (eg mass, starformation rate) most strongly control AGN luminosity. We will also perform the cleanest measurement yet of how radio emission, X-ray emission and BH mass are related.

我们的研究涉及致密天体，即白矮星、中子星和黑洞（BH），既有恒星大小的，也有超大质量的（SMBH）。我们的目标是了解它们如何演化以及如何产生辐射。X射线双星（XRB）包含BH和中子星周围的明亮吸积盘，可以详细检查这些吸积盘如何变化。由于它们变化很快，因此可以对变异性进行许多测量，使我们能够了解不同频率的变异性如何联系在一起。使用这些测量，我们可以测试有关物质如何以及为何穿过圆盘落入的基本想法。利用红外发射的变化，我们可以观察射流的变化，并了解圆盘如何为我们在 XRB 中看到的相对论性射流提供能量。射流的强烈无线电发射通常伴随着吸积，特别是在 XRB 的“硬”状态下。我们将研究 LOFAR 和 eMERLIN 等新天文台中所见的射电发射与 X 射线发射的关系，作为研究吸积/流出连接的一种手段。我们将研究为什么在硬态源中，潜在的吸积能有时会有效地转化为辐射，有时则不能。我们将测量黑洞的自旋，这对于确定有多少吸积能量可以作为辐射释放出来非常重要。研究双星系统中的大质量恒星及其演化可以为了解银河系和附近星系中最近的恒星形成提供重要的见解。 SMC 演化的恒星群表明最近与其伴星系的湍流相互作用，产生了一个非常活跃的恒星形成时期。许多大质量恒星都经历了超新星阶段，产生了大量的中子星。对这一群体的研究揭示了对恒星演化本质的重要见解。吸积白矮星（AWD）在天体物理学上具有重要意义。它们包括 Ia 型超新星祖细胞，驱动其进化的过程与许多其他环境相关。在这里，我们将扩展我们在全轮驱动和相关系统发展方面的领先工作。我们将为AWD实现新的演化轨迹，直接探测第一个亚恒星次级，确定AWD的空间密度，搜索“死”AWD并确认第一个双简并SN Ia祖星。我们将研究恒星质量BH和SMBH（即AGN）之间的关系，询问诸如可变性时间尺度或能带之间的时间滞后等属性是否仅与质量成比例，或者也与质量成比例 增生率。我们将看看有喷流的活动星系核与没有喷流的活动星系核是否有不同的变化，以及 X 射线和伽马射线是否有不同的变化。我们将观察光学和无线电变化如何与有或没有喷流的 AGN 中的 X 射线变化相关。因此，在不同的活动星系核类型中，我们将确定不同波段的发射是如何、在何处产生的，以及它们为何不同。来自超大质量黑洞的大型喷流可以延伸数百万光年的距离，不仅将能量传输到它们的宿主星系，而且还传输到周围的星系群或星系团。这种能量输入对于星系和星团的形成和演化起着重要作用。我们将使用新的无线电设施，例如LOFAR 和 e-MERLIN，用于测量不同射电强 AGN 群体的能量影响并研究其生命周期，以了解它们在星系演化中的作用。SMBH 可能存在于所有星系的核中，但由于吸积率非常低，通常无法检测到。为了研究这些主宰当地宇宙的低光度活动星系核，我们正在对附近星系的最佳样本——帕洛马样本进行敏感的无线电和X射线调查，以找到微弱的活动星系核，并确定哪些宿主星系特性（例如质量、恒星形成率）对活动星系核的光度最有影响。我们还将对无线电发射、X 射线发射和 BH 质量之间的关系进行迄今为止最干净的测量。

项目成果

The flux-dependent X-ray time lags in NGC 4051

• DOI: 10.1093/mnras/stt1391
• 发表时间: 2013-07
• 期刊: Monthly Notices of the Royal Astronomical Society
• 影响因子: 4.8
• 作者: W. Alston;S. Vaughan;P. Uttley

Swift J1357.2-0933: the faintest black hole?

• DOI: 10.1093/mnras/stu1487
• 发表时间: 2014-04
• 期刊: Monthly Notices of the Royal Astronomical Society
• 影响因子: 4.8
• 作者: M. A. Padilla;M. A. Padilla;R. Wijnands;N. Degenaar;T. Muñoz-Darias;J. Casares;J. Casares;R. Fender

Ultraviolet and X-ray variability of NGC 4051 over 45 days with XMM-Newton and Swift

使用 XMM-Newton 和 Swift 测量 NGC 4051 45 天内的紫外线和 X 射线变化

• DOI: 10.1093/mnras/sts320
• 发表时间: 2012
• 期刊: Monthly Notices of the Royal Astronomical Society
• 影响因子: 4.8
• 作者: Alston W

Introducing the CTA concept

• DOI: 10.1016/j.astropartphys.2013.01.007
• 发表时间: 2013-03-01
• 期刊: ASTROPARTICLE PHYSICS
• 影响因子: 3.5
• 作者: Acharya, B. S.;Actis, M.;Zychowski, P.
• 通讯作者: Zychowski, P.

A return to strong radio flaring by Circinus X-1 observed with the Karoo Array Telescope test array KAT-7

卡鲁阵列望远镜测试阵列 KAT-7 观察到圆规座 X-1 恢复强烈射电耀斑

• DOI: 10.1093/mnras/stt860
• 发表时间: 2013
• 期刊: Monthly Notices of the Royal Astronomical Society
• 影响因子: 4.8
• 作者: Armstrong R