The majority of galactic chemical evolution models assumes the instantaneous mixing approximation (IMA). This assumption is probably not realistic as indicated by the existence of chemical inhomogeneities, although current chemical evolution models of the Milky Way can reproduce the majority of the observational constraints under the IMA. The aim of this paper is to test whether relaxing this approximation in a detailed chemical evolution model can improve or worsen the agreement with observations. To do that, we investigated two possible causes for relaxing of the instantaneous mixing: i) the ``galactic fountain time delay effect'' and ii) the ``metal cooling time delay effect''. We found that the effect of galactic fountains is negligible if an average time delay of 0.1 Gyr, as suggested in a previous paper, is assumed. Longer time delays produce differences in the results but they are not realistic. We also found that the O abundance gradient in the disk is not affected by galactic fountains. The metal cooling time delays produce strong effects on the evolution of the chemical abundances only if we adopt stellar yields depending on metallicity. If instead, the yields computed for to the solar chemical composition are adopted, negligible effects are produced, as in the case of the galactic fountain delay. The relaxation of the IMA by means of the galactic fountain model, where the delay is considered only for massive stars and only in the disk, does not affect the chemical evolution results. The combination of metal dependent yields and time delay in the chemical enrichment from all stars starting from the halo phase, instead, produces results at variance with observations.
The Milky and its Gas: Cold Fountains and Accretion
银河系正在从下落的高速云中获取气体。这些物质进入了一个盘-晕界面，在许多地方都充满了HI云，这些云是通过与恒星形成有关的过程从盘中喷射出来的。史密斯云是一个非凡的例子，高速云将相对低金属含量的气体$>10^6$ M $_{\odot}$带入银河系。它可能是一个更大的流的一部分，其中的组件现在正在通过磁盘。
A detection of H$_2$ in a high velocity cloud toward the Large Magellanic Cloud
这项工作提出了一个新的检测H $_2$吸收产生的高速云（HVC）与银河系或大麦云（LMC）。这种吸收剂是在大麦哲伦星系恒星Sk-70 $^\circ$ 32的远紫外光谱探测器档案中发现的。这是在银河系晕中发现的第五个被充分表征的H $_2$吸收体，也是在麦哲伦流和桥之外发现的第二个这样的吸收体。吸收体的静止中心速度为$+$ 140 km s $^{-1}$，H $_2$柱密度为$10^{17.5}$ cm $^{-2}$。它最有可能是在较温暖和较弥散的晕云中较冷和相对致密的包裹体（$T\approx 75$ K，$n_{\rm H}\sim 100$ cm $^{-3}$）的一部分。这个晕云可能是仍在上升的银河系喷泉流的一部分，也可能是大麦云云的外流。
Co-evolution of the Milky Way high- and low-α sequences with chemical evolution models
INAF, Osservatorio Astronomico di Trieste（意大利国家天体物理研究所，的里雅斯特天文台）；IFPU, Institute for Fundamental Physics of the Universe（宇宙基础物理研究所）；Dipartimento di Fisica, Sezione di Astronomia, Università di Trieste（的里雅斯特大学，物理系，天文学部）；INFN Sezione di Trieste（意大利国家核物理研究所，的里雅斯特分部）
本文通过改进的化学演化模型探讨银河盘内高α和低α序列的共同演化及古老低α星的存在，解释了观测到的[α/Fe] vs [Fe/H]图谱。
Milky Way Mapper decoded abundances -- II: From patterns to paths
Research School of Astronomy and Astrophysics, Australian National University（澳大利亚国立大学天文与天体物理研究学院）；Department of Astronomy, Columbia University（哥伦比亚大学天文学系）；Center for Astrophysics and Space Astronomy, Department of Astrophysical and Planetary Sciences, University of Colorado（科罗拉多大学天体物理学与行星科学系天体物理学与空间天文中心）；Department of Physics & Astronomy, University of Utah（犹他大学物理与天文学系）；Department of Physics and Astronomy, Vanderbilt University（范德堡大学物理与天文学系）；Center for Computational Astrophysics, Flatiron Institute（平顿研究所计算天体物理学中心）；School of Physics and Astronomy, Monash University（莫纳什大学物理与天文学院）；Department of Astronomy, The Ohio State University（俄亥俄州立大学天文学系）；Center for Cosmology and Astroparticle Physics (CCAPP), The Ohio State University（俄亥俄州立大学宇宙学与高能粒子物理中心）
The AGORA High-resolution Galaxy Simulations Comparison Project. IX - Part 1: Effects of a Major Galaxy Merger on Star Formation of a Milky Way-mass Galaxy Progenitor
National Center for Supercomputing Applications（国家超级计算应用中心）；Seoul National University（首尔国立大学）；Universidad Complutense de Madrid（马德里康普顿斯大学）；Lund University（隆德大学）
Phase spirals across galactic disks I: Exploring dynamical influences on winding
Columbia University（哥伦比亚大学）；University of Surrey（萨里大学）；Stockholm University（斯德哥尔摩大学）；Princeton University（普林斯顿大学）；University of Edinburgh（爱丁堡大学）；University of Massachusetts at Amherst（马萨诸塞大学阿默斯特分校）
NEFERTITI: Linking early galaxy formation to the assembly of the Milky Way
INAF/Osservatorio Astrofisico di Arcetri（意大利国家天体物理研究所阿切特里天文台）；Cosmic Dawn Center (DAWN)（宇宙黎明中心）；Niels Bohr Institute, University of Copenhagen（哥本哈根大学尼尔斯玻尔研究所）；Instituto de Astrofísica de Canarias（加那利群岛天体物理研究所）；Universidad de La Laguna（拉古纳大学）
Fast Dynamical Modelling of Milky Way Globular Clusters -- II. Impacts of Black Hole Prescriptions
Saint Mary’s University（圣玛丽大学）；Universitat de Barcelona (UB)（巴塞罗那大学）；ICREA（加泰罗尼亚高级研究院）；Institut d’Estudis Espacials de Catalunya (IEEC)（加泰罗尼亚空间研究所）；Zentrum für Astronomie der Universität Heidelberg, Institut für Theoretische Astrophysik（海德堡大学天文学中心理论天体物理研究所）；Max Planck Institute for Astronomy（马克斯·普朗克天文学研究所）；Department of Physics and Astronomy, University of Heidelberg（海德堡大学物理与天文系）
The AGORA High-resolution Galaxy Simulations Comparison Project. VIII: Disk Formation and Evolution of Simulated Milky Way Mass Galaxy Progenitors at $1<z<5$
Seoul National University（首尔大学）；University of Illinois at Urbana-Champaign（伊利诺伊大学厄巴纳-香槟分校）；Osaka University（大阪大学）；University of Tokyo（东京大学）；University of Nevada Las Vegas（内华达大学拉斯维加斯分校）；University of Connecticut（康涅狄格大学）
The Dark Matter Diffused Supernova Neutrino Background
Arizona State University（亚利桑那州立大学）；Virginia Tech（弗吉尼亚理工大学）；High Energy Accelerator Research Organization (KEK)（高能加速器研究机构）；Massachusetts Institute of Technology（麻省理工学院）；Harvard University（哈佛大学）
The AGORA High-resolution Galaxy Simulations Comparison Project. IX - Part 2: Effects of a Major Galaxy Merger on the Stellar Morphology of a Milky Way-mass Galaxy Progenitor
Center for AstroPhysical Surveys, National Center for Supercomputing Applications（国家超级计算应用中心天文物理调查中心）；Center for Theoretical Physics, Department of Physics and Astronomy, Seoul National University（首尔国立大学物理与天文学系理论物理中心）；Departamento de Física de la Tierra y Astrofísica, Fac. de C.C. Físicas, Universidad Complutense de Madrid（马德里康普顿斯大学理学院地球与天体物理学系）；Instituto de Física de Partículas y del Cosmos, IPARCOS, Fac. C.C. Físicas, Universidad Complutense de Madrid（马德里康普顿斯大学理学院粒子与宇宙物理研究所）；Lund Observatory, Division of Astrophysics, Department of Physics, Lund University（隆德大学物理系天体物理学部隆德天文台）
The Two-infall Model Revisited: Constraints on Milky Way Bulge Assembly from >30,000 Galactic Chemical Evolution Models and Machine Learning
University of Wyoming（怀俄明大学）；Space Telescope Science Institute（太空望远镜科学研究所）；Department of Astronomy, University of Florida（佛罗里达大学天文学系）；University of Bayreuth（拜罗伊特大学）；Konkoly Observatory, HUN-REN Research Centre for Astronomy and Earth Sciences（孔科利天文台，匈牙利研究与教育网络地球与天文学研究中心）；CSFK, MTA Centre of Excellence（CSFK，匈牙利科学院卓越中心）；Department of Physics and Astronomy, UCLA（加州大学洛杉矶分校物理与天文学系）
Effects of Resolution and Local Stability on Galactic Disks: I. Multiple Spiral Mode Formation via Swing Amplification
Universität Potsdam, Institut für Physik und Astronomie（波茨坦大学物理与天文学系）；Department of Astronomy and Yonsei University Observatory, Yonsei University（延世大学天文学系及延世大学天文台）
