We study the radial motions of cold, star-forming gas in the secular evolution phase of a set of 14 magnetohydrodynamical cosmological zoom-in simulations of Milky Way-mass galaxies. We study the radial transport of material within the disc plane in a series of concentric rings. For the gas in each ring at a given time we compute two quantities as a function of time and radius: 1) the radial bulk flow of the gas; and 2) the radial spread of the gas relative to the bulk flow. Averaging the data from all the halos, we find that the radial spread increases with radius in the form of a power law with strong secondary dependencies on the fraction of accreted material and the local radial velocity dispersion of the gas. We find that the bulk motion of gas is well described in the inner disc regions by a radially-independent mean inward flow speed of $-$2.4 km s$^{-1}$. The spread around this value relates to the change in angular momentum of the gas and also the amount of accreted material. These scalings from fully cosmological, MHD simulations of galaxy formation can then be used in semi-analytic models to better parameterise the radial flow of gas in discs.
Satellites Around Milky Way Analogs: Tension in the Number and Fraction of Quiescent Satellites Seen in Observations Versus Simulations
比较了SAGA-II与APOSTLE和Auriga宇宙学放大模拟软件包中银河系卫星的成星特性。我们使用档案GALEX紫外成像作为SAGA-II样本的恒星形成指标，并推导出恒星形成率（SFR）与APOSTLE和御夫座的恒星形成率进行比较。我们比较我们的检测率从NUV和FUV波段的SAGA-II H $α$检测，发现它们是广泛一致的超过$85\%$的观测卫星检测到的所有三个示踪剂。我们应用相同的空间选择标准，围绕SAGA-II主机选择卫星周围的MW类主机在APOSTLE和御夫座。我们发现非常好的整体协议，在派生的SFR的恒星形成卫星，以及恒星形成卫星的数量，每个主机在观测和模拟样本。然而，在SAGA-II样本中淬灭卫星的数量和比例显着低于APOSTLE和御夫座低于恒星质量的$M_*\sim10^{8}\,M_{\odot}$，即使当SAGA-II的不完整性和闯入者的修正。这种差异是强大的模拟的分辨率和持续替代恒星形成示踪剂时，采用。我们认为，这种分歧是不容易解释的变幻莫测的观察或模拟样品考虑在这里，这表明一个真正的差异，可能会告知周围MW类似物的卫星种群的物理。
Auriga Superstars: Improving the resolution and fidelity of stellar dynamics in cosmological galaxy simulations
Max-Planck-Institut für Astrophysik（马克斯·普朗克天体物理学研究所）；Institute for Computational Cosmology, Department of Physics, Durham University（达勒姆大学物理学院计算宇宙学研究所）；Astrophysics Research Institute, Liverpool John Moores University（利物浦约翰摩尔斯大学天体物理学研究所）；Argonne Leadership Computing Facility, Argonne National Laboratory（阿贡国家实验室阿贡领导计算设施）；Departamento de Astronomía, Universidad de La Serena（拉塞雷纳大学天文学系）；Cardiff Hub for Astrophysics Research and Technology, School of Physics and Astronomy, Cardiff University（卡迪夫大学物理与天文学院卡迪夫天体物理学研究与技术中心）；Department of Astrophysics, University of Zurich（苏黎世大学天体物理学系）
FEASTS Compared with Simulations: Abnormally Irregular and Extended HI Morphologies at a Column Density of $10^{18}\,\text{cm}^{-2}$ in TNG50 and Auriga
Peking University（北京大学）；Max-Planck Institut für Astrophysik（马克斯·普朗克天体物理学研究所）
研究发现，在 TNG50 中，恒星反馈显著影响 $10^{18}\,\text{cm}^{-2}$ 的 HI 形态，而 AGN 反馈作用较弱，磁场有助于 HI 形态规整。
The diverse nature of spiral arms in the Auriga Superstars cosmological hydrodynamic simulations
Liverpool John Moores University（利物浦约翰摩尔斯大学）；Durham University（杜伦大学）；Max-Planck-Institut für Astrophysik（马克斯·普朗克天体物理学研究所）；Universidad de La Serena（拉塞雷纳大学）；Cardiff University（卡迪夫大学）；Universität Zürich（苏黎世大学）
