New Astronomy Reviews最新文献_第2页

IF 6 2区物理与天体物理

New Astronomy Reviews Pub Date : 2024-05-18 DOI: 10.1016/j.newar.2024.101694

Kareem El-Badry

{"title":"Gaia’s binary star renaissance","authors":"Kareem El-Badry","doi":"10.1016/j.newar.2024.101694","DOIUrl":"https://doi.org/10.1016/j.newar.2024.101694","url":null,"abstract":"<div><p>Stellar multiplicity is among the oldest and richest problems in astrophysics. Binary stars are a cornerstone of stellar mass and radius measurements that underpin modern stellar evolutionary models. Binaries are the progenitors of many of the most interesting and exotic astrophysical phenomena, ranging from type Ia supernovae to gamma ray bursts, hypervelocity stars, and most detectable stellar black holes. They are also ubiquitous, accounting for about half of all stars in the Universe. In the era of gravitational waves, wide-field surveys, and open-source stellar models, binaries are coming back stronger than a nineties trend. Much of the progress in the last decade has been enabled by the <em>Gaia</em> mission, which provides high-precision astrometry for more than a billion stars in the Milky Way. The <em>Gaia</em> data probe a wider range of binary separations and mass ratios than most previous surveys, enabling both an improved binary population census and discovery of rare objects. I summarize recent results in the study of binary stars brought about by <em>Gaia</em>, focusing in particular on developments related to wide (<span><math><mrow><mi>a</mi><mo>≳</mo><mn>100</mn></mrow></math></span> au) binaries, evidence of binarity from astrometric noise and proper motion anomaly, astrometric and radial velocity orbits from <em>Gaia</em> DR3, and binaries containing non-accreting compact objects. Limitations of the <em>Gaia</em> data, the importance of ground-based follow-up, and anticipated improvements with <em>Gaia</em> DR4 are also discussed.</p></div>","PeriodicalId":19718,"journal":{"name":"New Astronomy Reviews","volume":"98 ","pages":"Article 101694"},"PeriodicalIF":6.0,"publicationDate":"2024-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141084233","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Progress in multi-messenger observations and emission models of blazars 对炽星的多信使观测和发射模型研究进展

IF 6 2区物理与天体物理

New Astronomy Reviews Pub Date : 2023-12-29 DOI: 10.1016/j.newar.2023.101693

Gang Cao , Xiongfei Geng , Jiancheng Wang , Xiongbang Yang

引用次数: 0

Advances on the morphological classification of radio galaxies: A review 射电星系形态分类研究进展

IF 6 2区物理与天体物理

New Astronomy Reviews Pub Date : 2023-10-12 DOI: 10.1016/j.newar.2023.101685

Steven Ndung’u , Trienko Grobler , Stefan J. Wijnholds , Dimka Karastoyanova , George Azzopardi

{"title":"Advances on the morphological classification of radio galaxies: A review","authors":"Steven Ndung’u , Trienko Grobler , Stefan J. Wijnholds , Dimka Karastoyanova , George Azzopardi","doi":"10.1016/j.newar.2023.101685","DOIUrl":"https://doi.org/10.1016/j.newar.2023.101685","url":null,"abstract":"<div><p>Modern radio telescopes will generate, on a daily basis, data sets on the scale of exabytes for systems like the Square Kilometre Array (SKA). Massive data sets are a source of unknown and rare astrophysical phenomena that lead to discoveries. Nonetheless, this is only plausible with the exploitation of machine learning to complement human-aided and traditional statistical techniques. Recently, there has been a surge in scientific publications focusing on the use of machine/deep learning in radio astronomy, addressing challenges such as source extraction, morphological classification, and anomaly detection. This study provides a comprehensive and concise overview of the use of machine learning techniques for the morphological classification of radio galaxies. It summarizes the recent literature on this topic, highlighting the main challenges, achievements, state-of-the-art methods, and the future research directions in the field. The application of machine learning in radio astronomy has led to a new paradigm shift and a revolution in the automation of complex data processes. However, the optimal exploitation of machine/deep learning in radio astronomy, calls for continued collaborative efforts in the creation of high-resolution annotated data sets. This is especially true in the case of modern telescopes like MeerKAT and the LOw-Frequency ARray (LOFAR). Additionally, it is important to consider the potential benefits of utilizing multi-channel data cubes and algorithms that can leverage massive datasets without relying solely on annotated datasets for radio galaxy classification.</p></div>","PeriodicalId":19718,"journal":{"name":"New Astronomy Reviews","volume":"97 ","pages":"Article 101685"},"PeriodicalIF":6.0,"publicationDate":"2023-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49743667","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A critical review of period analyses and implications for mass exchange in W UMa eclipsing binaries: Paper 4 wuma重叠双星的周期分析及其质量交换意义:论文4

IF 6 2区物理与天体物理

New Astronomy Reviews Pub Date : 2023-08-14 DOI: 10.1016/j.newar.2023.101684

R.H. Nelson , D. Terrell , E.F. Milone

{"title":"A critical review of period analyses and implications for mass exchange in W UMa eclipsing binaries: Paper 4","authors":"R.H. Nelson , D. Terrell , E.F. Milone","doi":"10.1016/j.newar.2023.101684","DOIUrl":"https://doi.org/10.1016/j.newar.2023.101684","url":null,"abstract":"<div><p>This is the fourth paper in the series of analyses of times of minimum and period variations in W UMa eclipsing binaries, and the implications for mass exchange in these systems. In this paper, the systems discussed in Papers 1–3 for which analyses are relatively complete are sorted into three sections, arranged in order of degree of confidence that mass exchange occurrence is established and that the present rate of exchange has been determined. The higher-confidence systems are: 44 Boo, RZ Cam, VW LMi, AU Ser; the intermediate-confidence systems are: TY Boo, V1191 Cyg, AP Leo, ER Ori; and the lower-confidence systems are: AB And, XY Boo, AC Boo, AH Cnc, VW Cep, EZ Hya, XY Leo, W UMa, and GR Vir. A fourth section describes promising cases that require additional data and/or analyses. For the higher-confidence systems, selected analyses of the times of minimum and of the most comprehensive light curve (LC) and radial velocity (RV) suites of data have yielded mean mass changes to the more massive component of dM<sub>1</sub>/dt = +2.37 (13) × 10<sup>−7</sup> M<sub>ʘ</sub>/y for 44 Boo, +4.00 (14) × 10<sup>−8</sup> M<sub>ʘ</sub> /y for RZ Com, +2.53 (7) × 10<sup>−7</sup> M<sub>ʘ</sub> /y for VW LMi, and -1.98 (11) × 10<sup>−7</sup> M<sub>ʘ</sub> /y for AU Ser.</p></div>","PeriodicalId":19718,"journal":{"name":"New Astronomy Reviews","volume":"97 ","pages":"Article 101684"},"PeriodicalIF":6.0,"publicationDate":"2023-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49767003","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Empirical constraints on turbulence in proto-planetary discs 原行星盘中湍流的经验约束

IF 6 2区物理与天体物理

New Astronomy Reviews Pub Date : 2023-06-01 DOI: 10.1016/j.newar.2023.101674

Giovanni P. Rosotti

{"title":"Empirical constraints on turbulence in proto-planetary discs","authors":"Giovanni P. Rosotti","doi":"10.1016/j.newar.2023.101674","DOIUrl":"https://doi.org/10.1016/j.newar.2023.101674","url":null,"abstract":"<div><p>Proto-planetary discs, the birth environment of planets, are an example of a structure commonly found in astrophysics, accretion discs. Identifying the mechanism responsible for accretion is a long-standing problem, dating back several decades. The common picture is that accretion is a consequence of turbulence, with several instabilities proposed for its origin. While traditionally this field used to be a purely theoretical endeavour, the landscape is now changing thanks mainly to new observational facilities such as the ALMA radio interferometer. Thanks to large improvements in spatial and spectral resolution and sensitivity (which have enabled the study of disc substructure, kinematics and surveys of large disc populations), multiple techniques have been devised to observationally measure the amount of turbulence in discs. This review summarises these techniques, ranging from attempts at direct detection of turbulence from line broadening, to more indirect approaches that rely on properties of the dust or consider the evolution of global disc properties (such as masses, radii and accretion rates) for large samples, and what their findings are. Multiple lines of evidence suggest that discs are in fact not as turbulent as thought one decade ago. On the other hand, direct detection of turbulence in some discs and the finite radial extent of dust substructures and in some cases the finite vertical extent strongly indicate that turbulence must be present at some level in proto-planetary discs. It is still an open question whether this amount of turbulence is enough to power accretion or if this is instead driven by other mechanisms, such as MHD winds.</p></div>","PeriodicalId":19718,"journal":{"name":"New Astronomy Reviews","volume":"96 ","pages":"Article 101674"},"PeriodicalIF":6.0,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49763964","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 3

New nomenclature rules for meteor showers adopted 采用新的流星雨命名规则

IF 6 2区物理与天体物理

New Astronomy Reviews Pub Date : 2023-06-01 DOI: 10.1016/j.newar.2022.101671

Tadeusz J. Jopek , Mária Hajduková , Regina Rudawska , Masahiro Koseki , Gulchehra Kokhirova , Luboš Neslušan

引用次数: 2

Rational ignorance in the search for extra-terrestrial life 在寻找外星生命的过程中，理性的无知

IF 6 2区物理与天体物理

New Astronomy Reviews Pub Date : 2023-06-01 DOI: 10.1016/j.newar.2023.101675

Edward D. Zanders

{"title":"Rational ignorance in the search for extra-terrestrial life","authors":"Edward D. Zanders","doi":"10.1016/j.newar.2023.101675","DOIUrl":"https://doi.org/10.1016/j.newar.2023.101675","url":null,"abstract":"<div><p>The question “are we alone in the universe?” has been asked through the ages and is beginning to be addressed by deploying spacecraft and advanced observatories capable of detecting biological signatures. Apart from the certainty that life exists on the Earth, there is no clear evidence at the time of writing for extra-terrestrial life (also termed <em>exo-life</em>). Although the sheer number of potentially habitable extrasolar planets in our galaxy alone makes a compelling case for widespread exo-life if taken in isolation, the constraints on the emergence of life imposed by chemistry and biology provide a counterbalance to this optimistic view. In the absence of any clear sign of exo-life and therefore our ignorance about whether it exists or not, the only way forward is to apply scientific knowledge in a rational way to discriminate between different scenarios until such a time that real evidence is forthcoming, if at all. This article reviews the main features of current astrobiological research to speculate on the likelihood of each critical transition in the development of living entities, emphasising the involvement of chemistry and informational macromolecules. It concludes that carbon-based compounds may be widespread on and in exoplanets, but the organisation of these prebiotic molecules into cellular structures with anything like the complexity of the primitive organisms on Earth could be very rare or non-existent. However, if such organisms do arise, the path to multicellularity and the functional organisation required for human capabilities may not be so daunting. Some of the key genetic features required for this development may already be present in primitive cells ready to be activated or repurposed.</p></div>","PeriodicalId":19718,"journal":{"name":"New Astronomy Reviews","volume":"96 ","pages":"Article 101675"},"PeriodicalIF":6.0,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49744324","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Ultraluminous X-ray sources 超亮x射线源

IF 6 2区物理与天体物理

New Astronomy Reviews Pub Date : 2023-06-01 DOI: 10.1016/j.newar.2022.101672

Andrew King , Jean-Pierre Lasota , Matthew Middleton

引用次数: 6

Review of latest advances on dark matter from the viewpoint of the Occam razor principle 从奥卡姆剃刀原理的观点回顾暗物质的最新进展

IF 6 2区物理与天体物理

New Astronomy Reviews Pub Date : 2023-06-01 DOI: 10.1016/j.newar.2023.101673

Eugene Oks

引用次数: 5

Persistent mysteries of jet engines, formation, propagation, and particle acceleration: Have they been addressed experimentally? 喷气发动机、形成、传播和粒子加速的持久谜团:它们在实验上得到解决了吗?

IF 6 2区物理与天体物理

New Astronomy Reviews Pub Date : 2022-12-01 DOI: 10.1016/j.newar.2022.101661

Eric G. Blackman , Sergey V. Lebedev

{"title":"Persistent mysteries of jet engines, formation, propagation, and particle acceleration: Have they been addressed experimentally?","authors":"Eric G. Blackman , Sergey V. Lebedev","doi":"10.1016/j.newar.2022.101661","DOIUrl":"10.1016/j.newar.2022.101661","url":null,"abstract":"<div><p><span>The physics of astrophysical jets can be divided into three regimes: (i) engine and launch (ii) propagation and </span>collimation<span>, (iii) dissipation and particle acceleration. Since astrophysical jets comprise a huge range of scales and phenomena, practicality dictates that most studies of jets intentionally or inadvertently focus on one of these regimes, and even therein, one body of work may be simply boundary condition for another. We first discuss long standing persistent mysteries that pertain the physics of each of these regimes, independent of the method used to study them. This discussion makes contact with frontiers of plasma astrophysics more generally. While observations theory, and simulations, and have long been the main tools of the trade, what about laboratory experiments? Jet related experiments have offered controlled studies of specific principles, physical processes, and benchmarks for numerical and theoretical calculations. We discuss what has been accomplished on these fronts. Although experiments have indeed helped us to understand certain processes, proof of principle concepts, and benchmarked codes, they have yet to solved an astrophysical jet mystery on their own. A challenge is that experimental tools used for jet-related experiments so far, are typically not machines originally designed for that purpose, or designed with specific astrophysical mysteries in mind. This presents an opportunity for a different way of thinking about the development of future platforms: start with the astrophysical mystery and build an experiment to address it.</span></p></div>","PeriodicalId":19718,"journal":{"name":"New Astronomy Reviews","volume":"95 ","pages":"Article 101661"},"PeriodicalIF":6.0,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88524849","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 3