Within the cosmological concordance model, Cold Dark Matter (CDM) subhalos form the building blocks which merge hierarchically to more massive galaxies. Since intergalactic gas is accreted by massive galaxies, observable e.g. as high- velocity clouds (HVCs) around the Milky Way, with extremely low metallicities, these can be suggested to represent the baryonic content of primordial Dark Matter (DM) subhalos. Another possibility of their origin is that they stem from disrupted satellite galaxies, but in this case, these gas clouds move unaccompanied by a bound DM structure. Since HVCs are observed with long gas tails and with irregular substructures, numerical models are performed aiming at exploring their structure and compare them with observations. If HVCs are engulfed by DM subhalos, their gas must leave the DM gravitational potential and reflect this in their dynamics. On the other hand, the evolution and survival of pure gas models must be tested to distinguish between DM-dominated and DM-free clouds and to allow conclusions on their origin. The models demonstrate that purely baryonic HVCs with low masses are disrupted by ram-pressure stripping and Kelvin-Helmholtz instabilities, while more massive ones survive, losing their initially spherical shape and develop significant substructures including cometary elongations in the column density distribution ("head-tail structure"). On the contrary, HVCs with DM subhalos survive with more than 90% of their gas mass still bound and spherically shaped, approaching the Galactic disk like bullets. In addition, we find that velocity gradients along the cometary head-tail structures does not necessarily offer a possibility to distinguish between DM-dominated and purely gaseous HVCs. Comparison of models with observations let us conclude that HVCs are not embedded in a DM substructure and do not trace the cosmological subhalo population.
Multi-tracer mass bias in matched cosmic voids from SDSS DR7 and the ELUCID constrained simulation
Shanghai Astronomical Observatory（上海天文台）；Tsung-Dao Lee Institute & School of Physics and Astronomy, Shanghai Jiao Tong University（上海交通大学物理与天文学院、汤忠道研究院）；Shanghai Key Laboratory for Particle Physics and Cosmology, and Key Laboratory for Particle Physics, Astrophysics and Cosmology Ministry of Education, Shanghai Jiao Tong University（上海交通大学粒子物理与宇宙学上海市重点实验室、粒子物理、天体物理与宇宙学教育部重点实验室）
How DREAMS are made: Emulating Satellite Galaxy and Subhalo Populations with Diffusion Models and Point Clouds
Massachusetts Institute of Technology（麻省理工学院）；Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology（麻省理工学院卡夫利天体物理与空间研究所）；The NSF AI Institute for Artificial Intelligence and Fundamental Interactions（美国国家科学基金会人工智能与基本相互作用AI研究所）；Northwestern University（西北大学）；Center for Computational Astrophysics, Flatiron Institute（弗拉蒂伦研究所计算天体物理中心）；Princeton University（普林斯顿大学）；Anthropic（Anthropic公司）；Center for Theoretical Physics, Massachusetts Institute of Technology（麻省理工学院理论物理中心）；Harvard University（哈佛大学）
An improved formalism for measuring the dark matter subhalos mass by its gravitational wake
Instituto de Astrofísica de La Plata (IALP, CONICET)（拉普拉塔天体物理研究所）；Instituto de Astronomía Teórica y Experimental, (IATE - UNC and CONICET CCT Córdoba), Observatorio Astronómico de Córdoba, Universidad Nacional de Córdoba（理论与实验天文研究所）；Universidad Nacional de Córdoba（科尔多瓦国立大学）
本文提出了一种改进方法，通过引力 wake 测量暗物质次亚晕质量，利用非均匀背景和云的圆周速度提高估计精度。
Signatures of dark subhalos in dwarf spheroidal galaxies: I. Fluctuations in surface density
Institute for Astronomy, University of Edinburgh（爱丁堡大学天体物理研究所）；Centre for Statistics, University of Edinburgh（爱丁堡大学统计中心）；McWilliams centre for Cosmology and Astrophysics, Department of Physics, Carnegie Mellon University（卡内基梅隆大学物理系麦克威廉斯宇宙学与天体物理学中心）
CWTHF: Subhalo Identification with Continuous Wavelet Transform
Center for Theoretical Physics, College of Physics, Jilin University（吉林大学物理学院理论物理中心）；Key Laboratory of Material Simulation Methods & Software of Ministry of Education, College of Physics, Jilin University（吉林大学物理学院教育部材料模拟方法与软件重点实验室）；Center for High Energy Physics, Peking University（北京大学高能物理研究中心）
Semi-Analytic Modeling of Dark Matter Subhalo Encounters with Thin Stellar Streams: Statistical Predictions for GD-1-like Streams in CDM
C.N. Yang Institute for Theoretical Physics, Stony Brook University（纽约州立大学石溪分校杨振宁理论物理研究所）；Department of Physics and Astronomy, University of California, Irvine（加州大学尔湾分校物理与天文学系）；Center for Computational Astrophysics, Flatiron Institute（平顿研究所计算天体物理学中心）
Measurement of Substructure from the Kinematics of the GD-1 Stellar Stream
Princeton University（普林斯顿大学）；The Observatories of the Carnegie Institution for Science（卡内基科学研究所天文台）；Center for Computational Astrophysics, Flatiron Institute（平顿研究所计算天体物理学中心）
Signatures of dark subhaloes in dwarf spheroidal galaxies: II. Transient and localised kinematic features
Institute for Astronomy, University of Edinburgh（爱丁堡大学天文研究所）；Royal Observatory, Blackford Hill, Edinburgh（皇家天文台）；Institute of Corpuscular Physics (IFIC), CSIC–Universitat de València（粒子物理研究所（IFIC），西班牙国家研究委员会-巴伦西亚大学）；Space Telescope Science Institute（太空望远镜科学研究所）；Center for Astrophysical Sciences, The William H. Miller III Department of Physics & Astronomy, Johns Hopkins University（约翰霍普金斯大学天体物理学中心威廉H米勒三世物理与天文学系）；McWilliams centre for Cosmology and Astrophysics, Department of Physics, Carnegie Mellon University（卡内基梅隆大学物理学院麦克休斯宇宙学与天体物理中心）
CH as a Molecular Gas Tracer and C-Shock Tracer Across a Molecular Cloud Boundary in Taurus
我们提出了新的观测所有三个基态跃迁的次甲基（CH）自由基和所有四个基态跃迁的羟基（OH）自由基对一个尖锐的边界区域的金牛座分子云。这些数据与现有的CO和灰尘图像进行了分析。推导出的CH丰度与以前的半透明云（$0.8\le A_{v} \le 2.1$等）的观测结果一致。在此消光范围内，$X({\rm CH})$ -因子在$(1.0\pm0.06)\times 10^{22}$ $\rm {cm^{-2}~K^{-1}~km^{-1}~s}$处几乎为常数，其色散小于更广泛使用的分子示踪剂CO和OH的色散。结果表明，CH是一个更好的总柱密度在这样的中间消光范围比CO或OH的示踪剂。与以前的观测结果相比，CH在1等灭绝以下是过剩的。这种CH的过量与C型休克的存在是一致的。CH有两个运动学分量，当从云外向云内移动时，其中一个从5.3 km s $^{-1}$移动到6 km s，而另一个保持在6.8 km s $^{-1}$。这些速度行为与以前的OH观测结果完全吻合。这两个运动分量的移动表明在边界区域的碰撞流或气体流动，这可能是C-激波的原因。
Tracing the formation of molecular clouds via [CII], [CI] and CO emission
如果我们有一个可靠的观测示踪剂来追踪形成云的气流，那么我们对分子云如何在星际介质（ISM）中形成的理解将大有帮助。单电离和中性碳（[CII]，[CI]）的精细结构发射和CO的旋转线发射都被观察到与分子云。然而，目前还不清楚这些示踪剂是否可以用来研究气体流入到正在聚集的云上，或者它们是否主要追踪已经聚集的云。在本文中，我们解决这个问题的帮助下，高分辨率的分子云的形成，包括一个复杂的化学和热物理的ISM治疗模拟。我们的模拟表明，[CI]和CO排放的痕量气体主要是分子，密度n ~ 500-1000 cm $^{-3}$，远大于流入气体的密度。[CII]追踪早期主要为原子的低密度物质（n ~ 100 cm $^{-3}$）。大部分的[CII]发射跟踪与[CI]或CO发射相同的结构，但一些出现在流入的气体中。不幸的是，这种辐射非常微弱，用现有的观测设施很难探测到，即使是位于星际辐射场升高的区域的云。
Forecasting Dark Matter Subhalo Constraints from Stellar Streams using Implicit Likelihood Inference
Northwestern University（西北大学）；NSF-Simons AI Institute for the Sky（NSF-西蒙斯天空AI研究所）；Carnegie Mellon University（卡内基梅隆大学）；University of Washington（华盛顿大学）；University of Chicago（芝加哥大学）；Fermi National Accelerator Laboratory（费米国家加速器实验室）；University of Surrey（萨里大学）；Newcastle University（纽卡斯尔大学）；Lund University（隆德大学）
Molecular cloud dispersal traced by the ionized carbon 158 micron line
I. Physikalisches Institut, Universität zu Köln（科隆大学第一物理研究所）；Green Bank Observatory（格林班克天文台）；University of Maryland, Department of Astronomy（马里兰大学天文学系）；Leiden Observatory（莱顿天文台）；SOFIA Science Center, USRA, NASA Ames Research Center（NASA阿姆斯研究中心USRA SOFIA科学中心）；Astronomisches Rechen-Institut, ZfA Universität Heidelberg（海德堡大学ZfA天体计算研究所）；Center for Gravitational Waves and Cosmology, West Virginia University（西弗吉尼亚大学引力波与宇宙学中心）
Testing subhalo abundance matching with galaxy kinematics
University of Oxford（牛津大学）；University of Cambridge（剑桥大学）；University of Manchester（曼彻斯特大学）；University of Portsmouth（朴茨茅斯大学）；University of the Western Cape（西开普大学）
