Annual Review of Astronomy and Astrophysics最新文献_第4页

The Cold Interstellar Medium of Galaxies in the Local Universe 局域宇宙中星系的冷星际介质

IF 33.3 1区物理与天体物理 Q1 Earth and Planetary Sciences

Annual Review of Astronomy and Astrophysics

Pub Date : 2022-02-01 DOI: 10.1146/annurev-astro-021022-043545

A. Saintonge, B. Catinella

The cold interstellar medium (ISM) plays a central role in the galaxy evolution process. It is the reservoir that fuels galaxy growth via star formation, the repository of material formed by these stars, and a sensitive tracer of internal and external processes that affect entire galaxies. Consequently, significant efforts have gone into systematic surveys of the cold ISM of the galaxies in the local Universe. This review discusses the resulting network of scaling relations connecting the atomic and molecular gas masses of galaxies with their other global properties (stellar masses, morphologies, metallicities, star-formation activity…) and their implications for our understanding of galaxy evolution. Key take-home messages are as follows: ▪ From a gas perspective, there are three main factors that determine the star-formation rate of a galaxy: the total mass of its cold ISM, how much of that gas is molecular, and the rate at which any molecular gas is converted into stars. All three of these factors vary systematically across the local galaxy population. ▪ The shape and scatter of both the star-formation main sequence and the mass–metallicity relation are deeply linked to the availability of atomic and molecular gas. ▪ Future progress will come from expanding our exploration of scaling relations into new parameter space (in particular, the regime of dwarf galaxies), better connecting the cold ISM of large samples of galaxies with the environment that feeds them (the circumgalactic medium, in particular), and understanding the impact of these large scales on the efficiency of the star-formation process on molecular cloud scales. Expected final online publication date for the Annual Review of Astronomy and Astrophysics Volume 60 is August 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

冷星际介质（ISM）在星系演化过程中起着核心作用。它是通过恒星形成为星系生长提供燃料的库，是这些恒星形成的物质库，也是影响整个星系的内部和外部过程的敏感示踪剂。因此，对本地宇宙中星系的冷ISM进行了系统的研究。这篇综述讨论了星系的原子和分子气体质量与其其他全球性质（恒星质量、形态、金属性、恒星形成活动…）之间的比例关系网络，以及它们对我们理解星系演化的意义。关键带回家的信息如下：▪ 从气体的角度来看，有三个主要因素决定了一个星系的恒星形成速度：其冷ISM的总质量，有多少气体是分子气体，以及任何分子气体转化为恒星的速度。所有这三个因素在本地星系群中都有系统地变化。▪ 恒星形成主序列的形状和散射以及质量-金属性关系都与原子和分子气体的可用性密切相关。▪ 未来的进展将来自于将我们对比例关系的探索扩展到新的参数空间（特别是矮星系的状态），更好地将大样本星系的冷ISM与提供它们的环境（特别是环星系介质）联系起来，以及了解这些大尺度对分子云尺度上恒星形成过程效率的影响。《天文学和天体物理学年度评论》第60卷预计最终在线出版日期为2022年8月。请参阅http://www.annualreviews.org/page/journal/pubdates用于修订估算。

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引用次数: 33

Galaxy Formation and Reionization: Key Unknowns and Expected Breakthroughs by the James Webb Space Telescope 星系的形成和再电离：詹姆斯·韦伯太空望远镜的关键未知和预期突破

IF 33.3 1区物理与天体物理 Q1 Earth and Planetary Sciences

Annual Review of Astronomy and Astrophysics

Pub Date : 2021-10-25 DOI: 10.1146/annurev-astro-120221-044656

B. Robertson

The launch of the James Webb Space Telescope (JWST) in late 2021 marks a new start for studies of galaxy formation at high redshift ( z ≳ 6) during the era of cosmic reionization. JWST can capture sensitive, high-resolution images and multiobject spectroscopy in the IR that will transform our view of galaxy formation during the first billion years of cosmic history. This review summarizes our current knowledge of the role of galaxies in reionizing intergalactic hydrogen ahead of JWST, achieved through observations with the Hubble Space Telescope and ground-based facilities including Keck, the Very Large Telescope, Subaru, and the Atacama Large Millimeter/Submillimeter Array. We identify outstanding questions in the field that JWST can address during its mission lifetime, including with the planned JWST Cycle 1 programs. These findings include the following: ▪ Surveys with JWST have sufficient sensitivity and area to complete the census of galaxy formation at the current redshift frontier ( z ∼ 8–10). ▪ Rest-frame optical spectroscopy with JWST of galaxies will newly enable measures of star-formation rate, metallicity, and ionization at z ∼ 8–9, allowing for the astrophysics of early galaxies to be constrained. ▪ The presence of evolved stellar populations at z ∼ 8–10 can be definitively tested by JWST, which would provide evidence of star formation out to z ∼ 15. Expected final online publication date for the Annual Review of Astronomy Volume 60 is August 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

詹姆斯·韦伯太空望远镜（JWST）于2021年末发射，标志着研究宇宙再电离时代高红移（z≳6）星系形成的新开始。JWST可以在红外光谱中捕捉敏感、高分辨率的图像和多目标光谱，这将改变我们对宇宙历史前10亿年星系形成的看法。这篇综述总结了我们目前对JWST之前星系在星系间氢再电离中的作用的了解，这是通过哈勃太空望远镜和包括凯克、超大望远镜、斯巴鲁和阿塔卡马大型毫米/亚毫米阵列在内的地面设施的观测实现的。我们确定了JWST在其任务寿命期间可以解决的领域中的未决问题，包括计划中的JWST周期1项目。这些发现包括以下内容：▪ JWST的调查具有足够的灵敏度和面积，可以完成当前红移前沿（z～8-10）星系形成的普查。▪ JWST星系的静止框架光谱将新实现对恒星形成速率、金属丰度和z～8-9电离的测量，从而限制早期星系的天体物理学。▪ JWST可以对z～8-10的演化恒星群的存在进行明确的测试，这将为z～15的恒星形成提供证据。《天文学年度评论》第60卷预计最终在线出版日期为2022年8月。请参阅http://www.annualreviews.org/page/journal/pubdates用于修订估算。

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引用次数: 43

Spirals in Galaxies 星系中的螺旋

IF 33.3 1区物理与天体物理 Q1 Earth and Planetary Sciences

Annual Review of Astronomy and Astrophysics

Pub Date : 2021-10-11 DOI: 10.1146/annurev-astro-052920-104505

J. Sellwood, K. Masters

Spirals in galaxies have long been thought to be caused by gravitational instability in the stellar component of the disk, but discerning the precise mechanism had proved elusive. Tidal interactions, and perhaps bars, may provoke some spiral responses, but spirals in many galaxies must be self-excited. We survey the relevant observational data and aspects of disk dynamical theory. The origin of the recurring spiral patterns in simulations of isolated disk galaxies has recently become clear, and it is likely that the mechanism is the same in real galaxies, although evidence to confirm this supposition is hard to obtain. As transient spiral activity increases random motion, the patterns must fade over time unless the disk also contains a dissipative gas component. Continuing spiral activity alters the structure of the disks in other ways: reducing metallicity gradients and flattening rotation curves are two of the most significant. The overwhelming majority of spirals in galaxies have two- or three-fold rotational symmetry, indicating that the cool, thin disk component is massive. Spirals in simulations of halo-dominated disks instead manifest many arms and, consequently, do not capture the expected full spiral-driven evolution. We conclude by identifying areas where further work is needed. Expected final online publication date for the Annual Review of Astronomy Volume 60 is August 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

长期以来，星系中的螺旋一直被认为是由星系盘恒星成分的引力不稳定引起的，但事实证明，要辨别出确切的机制是难以捉摸的。潮汐相互作用，也许是条带，可能会引发一些螺旋反应，但许多星系中的螺旋必须是自激的。我们调查了相关的观测数据和圆盘动力学理论的各个方面。最近，孤立盘星系模拟中反复出现的螺旋模式的起源变得清晰起来，而且在真实星系中这种机制很可能是相同的，尽管很难获得证实这一假设的证据。随着瞬态螺旋活动增加随机运动，除非圆盘也包含耗散气体成分，否则模式必须随着时间的推移而消退。持续的螺旋活动以其他方式改变了圆盘的结构：降低金属度梯度和使旋转曲线变平是最重要的两个。星系中绝大多数的螺旋都具有两倍或三倍的旋转对称性，这表明冷却的薄圆盘成分是巨大的。光环主导的圆盘模拟中的螺旋反而表现出许多臂，因此，没有捕捉到预期的全螺旋驱动的进化。最后，我们确定了需要进一步工作的领域。《天文学年度评论》第60卷预计最终在线出版日期为2022年8月。请参阅http://www.annualreviews.org/page/journal/pubdates用于修订估算。

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引用次数: 14

Theory and Diagnostics of Hot Star Mass Loss 热星质量损失的理论与诊断

IF 33.3 1区物理与天体物理 Q1 Earth and Planetary Sciences

Annual Review of Astronomy and Astrophysics

Pub Date : 2021-09-16 DOI: 10.1146/annurev-astro-052920-094949

J. Vink

Massive stars have strong stellar winds that direct their evolution through the upper Hertzsprung–Russell diagram and determine the black hole mass function. Furthermore, wind strength dictates the atmospheric structure that sets the ionizing flux. Finally, the wind directly intervenes with the stellar envelope structure, which is decisive for both single-star and binary evolution, affecting predictions for gravitational wave events. Key findings of current hot star research include: ▪ The traditional line-driven wind theory is being updated with Monte Carlo and comoving frame computations, revealing a rich multivariate behavior of the mass-loss rate [Formula: see text] in terms of M, L, Eddington Γ, Teff, and chemical composition Z. Concerning the latter, [Formula: see text] is shown to depend on the iron (Fe) opacity, making Wolf–Rayet populations, and gravitational wave events dependent on host galaxy Z. ▪ On top of smooth mass-loss behavior, there are several transitions in the Hertzsprung–Russell diagram, involving bistability jumps around Fe recombination temperatures, leading to quasi-stationary episodic, and not necessarily eruptive, luminous blue variable and pre-SN mass loss. ▪ Furthermore, there are kinks. At 100 [Formula: see text] a high Γ mass-loss transition implies that hydrogen-rich, very massive stars have higher mass-loss rates than commonly considered. At the other end of the mass spectrum, low-mass stripped helium stars no longer appear as Wolf–Rayet stars but as optically thin stars. These stripped stars, in addition to very massive stars, are two newly identified sources of ionizing radiation that could play a key role in local star formation as well as at high redshift. Expected final online publication date for the Annual Review of Astronomy and Astrophysics Volume 60 is August 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

大质量恒星具有强大的恒星风，这些恒星风通过上赫罗图引导它们的演化，并决定黑洞的质量函数。此外，风力决定了设定电离通量的大气结构。最后，风直接干扰恒星包络结构，这对单恒星和双星的演化都是决定性的，影响了引力波事件的预测。当前热门恒星研究的主要发现包括：▪ 传统的线驱动风理论正在用蒙特卡罗和合并框架计算进行更新，揭示了质量损失率[公式：见正文]在M、L、EddingtonΓ、Teff和化学成分Z方面的丰富的多元行为。关于后者，[公式：参见正文]被证明取决于铁（Fe）的不透明度，使得Wolf–Rayet种群，以及依赖于宿主星系Z的引力波事件。▪ 除了平稳的质量损失行为外，赫氏-罗素图中还有几个跃迁，涉及Fe复合温度周围的双稳态跳跃，导致准平稳的幕式（不一定是爆发式）发光蓝色变量和SN前质量损失。▪ 此外，还有扭结。在100[公式：见正文]时，高Γ质量损失跃迁意味着富含氢的大质量恒星的质量损失率比通常认为的要高。在质谱的另一端，低质量剥离的氦星不再是Wolf–Rayet星，而是光学上较薄的恒星。除了大质量恒星外，这些被剥离的恒星是两个新发现的电离辐射源，它们可能在局部恒星形成和高红移中发挥关键作用。《天文学和天体物理学年度评论》第60卷预计最终在线出版日期为2022年8月。请参阅http://www.annualreviews.org/page/journal/pubdates用于修订估算。

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引用次数: 19

Tidal Disruption Events 潮汐中断事件

IF 33.3 1区物理与天体物理 Q1 Earth and Planetary Sciences

Annual Review of Astronomy and Astrophysics

Pub Date : 2021-09-08 DOI: 10.1146/annurev-astro-111720-030029

Suvi Gezari

The concept of stars being tidally ripped apart and consumed by a massive black hole (MBH) lurking in the center of a galaxy first captivated theorists in the late 1970s. The observational evidence for these rare but illuminating phenomena for probing otherwise dormant MBHs first emerged in archival searches of the soft X-ray ROSAT All-Sky Survey in the 1990s, but has recently accelerated with the increasing survey power in the optical time domain, with tidal disruption events (TDEs) now regarded as a class of optical nuclear transients with distinct spectroscopic features. Multiwavelength observations of TDEs have revealed panchromatic emission, probing a wide range of scales, from the innermost regions of the accretion flow to the surrounding circumnuclear medium. I review the current census of 56 TDEs reported in the literature, and their observed properties can be summarized as follows:

▪	The optical light curves follow a power-law decline from peak that scales with the inferred central black hole mass as expected for the fallback rate of the stellar debris, but the rise time does not.
▪	The UV-optical and soft X-ray thermal emission come from different spatial scales, and their intensity ratio has a large dynamic range and is highly variable, providing important clues as to what is powering the two components.
▪	They can be grouped into three spectral classes, and those with Bowen fluorescence line emission show a preference for a hotter and more compact line-emitting region, whereas those with only Heii emission lines are the rarest class.

恒星被潜伏在星系中心的巨大黑洞(MBH)潮汐撕裂和吞噬的概念在20世纪70年代末首次吸引了理论家。这些罕见但具有启发意义的现象的观测证据首次出现在20世纪90年代软x射线ROSAT全天巡天的档案搜索中，但最近随着光学时域巡天能力的增加而加速，潮汐中断事件(tde)现在被视为一类具有明显光谱特征的光学核瞬变。对tde的多波长观测揭示了全色发射，探测范围很广，从吸积流的最内层区域到周围的环核介质。我回顾了文献中报道的56个tde的当前普查，它们观察到的特性可以总结如下:▪光学光曲线遵循幂律下降，从峰值开始，与推断的中心黑洞质量成比例，如预期的恒星碎片的后退率，但上升时间不是。▪紫外光学和软x射线的热辐射来自不同的空间尺度，它们的强度比具有大的动态范围和高度可变，为两个组件的动力提供了重要线索。它们可以分为三种光谱类别，具有Bowen荧光发射线的光谱显示出对更热和更紧凑的线发射区域的偏好，而只有Heii荧光发射线的光谱则是最稀有的一类。

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引用次数: 0

Transneptunian Space

IF 33.3 1区物理与天体物理 Q1 Earth and Planetary Sciences

Annual Review of Astronomy and Astrophysics

Pub Date : 2021-09-08 DOI: 10.1146/annurev-astro-120920-010005

Brett Gladman, Kathryn Volk

We provide a nonspecialist overview of the current state of understanding of the structure and origin of our Solar System's transneptunian region (often called the Kuiper Belt), highlighting perspectives on planetesimal formation, planet migration, and the contextual relationship with protoplanetary disks. We review the dynamical features of the transneptunian populations and their associated differences in physical properties. We describe aspects of our knowledge that have advanced in the past two decades and then move on to current issues of research interest (which thus still have unclear resolution).

▪	The current transneptunian population consists of both implanted and primordial objects.
▪	The primordial (aka cold) population is a largely unaltered remnant of the population that formed in situ.
▪	The reason for the primordial cold population's current outer edge is unexplained.
▪	The large semimajor-axis population now dynamically detached from Neptune is critical for understanding the Solar System's history.
▪	Observational constraints on the number and orbits of distant objects remain poor.

我们提供了对太阳系外海王星区域(通常称为柯伊伯带)的结构和起源的当前理解状态的非专业概述，突出了对星子形成，行星迁移以及与原行星盘的背景关系的看法。我们回顾了跨海王星种群的动力学特征及其在物理性质上的相关差异。我们描述了过去二十年来我们的知识发展的各个方面，然后转向当前的研究兴趣问题(因此仍然没有明确的解决方案)。▪目前的跨海王星人口由植入物和原始物组成。▪原始(又名冷)种群是在原地形成的种群的大部分未改变的残余。▪原始寒冷种群目前处于外缘的原因无法解释。▪现在从海王星动态分离的大型半轴人口对于理解太阳系的历史至关重要。▪对遥远天体的数量和轨道的观测限制仍然很差。

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引用次数: 0

Carrington Events Carrington活动

IF 33.3 1区物理与天体物理 Q1 Earth and Planetary Sciences

Annual Review of Astronomy and Astrophysics

Pub Date : 2021-06-25 DOI: 10.1146/annurev-astro-112420-023324

H. Hudson

The Carrington event in 1859, a solar flare with an associated geomagnetic storm, has served as a prototype of possible superflare occurrence on the Sun. Recent geophysical (14C signatures in tree rings) and precise time-series photometry [the bolometric total solar irradiance (TSI) for the Sun, and the broadband photometry from Kepler and Transiting Exoplanet Survey Satellite, for the stars] have broadened our perspective on extreme events and the threats that they pose for Earth and for Earth-like exoplanets. This review assesses the mutual solar and/or stellar lessons learned and the status of our theoretical understanding of the new data, both stellar and solar, as they relate to the physics of the Carrington event. The discussion includes the event's implied coronal mass ejection, its potential “solar cosmic ray” production, and the observed geomagnetic disturbances based on the multimessenger information already available in that era. Taking the Carrington event as an exemplar of the most extreme solar event, and in the context of our rich modern knowledge of solar flare and/or coronal mass ejection events, we discuss the aspects of these processes that might be relevant to activity on solar-type stars, and in particular their superflares. ▪ The Carrington flare of 1859, though powerful, did not significantly exceed the magnitudes of the greatest events observed in the modern era. ▪ Stellar “superflare” events on solar-type stars may share common paradigms, and also suggest the possibility of a more extreme solar event at some time in the future. ▪ We benefit from comparing the better-known microphysics of solar flares and CMEs with the diversity of related stellar phenomena. Expected final online publication date for the Annual Review of Astronomy and Astrophysics, Volume 59 is September 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

1859年的卡林顿事件是一次带有地磁风暴的太阳耀斑，它是太阳上可能发生超巨星的原型。最近的地球物理（年轮中的14C特征）和精确的时间序列测光[太阳的测辐射热总太阳辐照度（TSI），以及开普勒和凌日外行星探测卫星对恒星的宽带测光]拓宽了我们对极端事件及其对地球和类地系外行星构成的威胁的看法。这篇综述评估了相互的太阳和/或恒星经验教训，以及我们对恒星和太阳新数据的理论理解状况，因为它们与卡林顿事件的物理有关。讨论内容包括该事件隐含的日冕物质抛射、其潜在的“太阳宇宙线”产生，以及基于那个时代已有的多信使信息观测到的地磁扰动。以卡林顿事件为最极端太阳事件的例子，在我们对太阳耀斑和/或日冕物质抛射事件的丰富现代知识的背景下，我们讨论了这些过程中可能与太阳型恒星活动相关的方面，特别是它们的超巨星。▪ 1859年的卡林顿耀斑虽然威力巨大，但并没有显著超过现代观测到的最大事件的规模。▪ 太阳型恒星上的恒星“超级巨星”事件可能有共同的模式，也表明在未来某个时候可能会发生更极端的太阳事件。▪ 我们从比较更为人所知的太阳耀斑和日冕物质抛射的微观物理学与相关恒星现象的多样性中受益。《天文学和天体物理学年度评论》第59卷预计最终在线出版日期为2021年9月。请参阅http://www.annualreviews.org/page/journal/pubdates用于修订估算。

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引用次数: 10

The Journey of a Radio Astronomer: Growth of Radio Astronomy in India 一个射电天文学家的旅程:印度射电天文学的发展

IF 33.3 1区物理与天体物理 Q1 Earth and Planetary Sciences

Annual Review of Astronomy and Astrophysics

Pub Date : 2021-04-19 DOI: 10.1146/ANNUREV-ASTRO-090120-014030

G. Swarup

In this autobiographical account, I first describe my family, then childhood and education in India. During 1953–55, I worked in the new field of radio astronomy at the Division of Radiophysics of ...

在这本自传中，我首先描述了我的家庭，然后是童年和在印度的教育。1953年至55年间，我在。。。

引用次数: 3

Exoplanet Statistics and Theoretical Implications 外行星统计及其理论意义

IF 33.3 1区物理与天体物理 Q1 Earth and Planetary Sciences

Annual Review of Astronomy and Astrophysics

Pub Date : 2021-03-03 DOI: 10.1146/annurev-astro-112420-020055

Wei Zhu, S. Dong

In the past few years, significant advances have been made in understanding the distributions of exoplanet populations and the architecture of planetary systems. We review the recent progress of planet statistics, with a focus on the inner ≲1-AU region of the planetary system that has been fairly thoroughly surveyed by the Kepler mission. We also discuss the theoretical implications of these statistical results for planet formation and dynamical evolution. Expected final online publication date for the Annual Review of Astronomy and Astrophysics, Volume 59 is September 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

在过去的几年里，在理解系外行星种群的分布和行星系统的结构方面取得了重大进展。我们回顾了行星统计的最新进展，重点是开普勒任务已经对行星系统的内部区域进行了相当彻底的调查。我们还讨论了这些统计结果对行星形成和动力学演化的理论意义。《天文学和天体物理学年度评论》第59卷预计最终在线出版日期为2021年9月。请参阅http://www.annualreviews.org/page/journal/pubdates用于修订估算。

引用次数: 55

Microarcsecond Astrometry: Science Highlights from Gaia 微弧秒天体测量:来自盖亚的科学亮点

IF 33.3 1区物理与天体物理 Q1 Earth and Planetary Sciences

Annual Review of Astronomy and Astrophysics

Pub Date : 2021-02-23 DOI: 10.1146/annurev-astro-112320-035628

Anthony G. A. Brown

Access to microarcsecond astrometry is now routine in the radio, infrared (IR), and optical domains. In particular, the publication of the second data release (Gaia DR2) from the Gaia mission made ...

微弧秒天体测量现在在无线电、红外和光学领域是常规的。特别是，盖亚任务的第二份数据发布(盖亚DR2)的发布使……

引用次数: 16