Nexus-CDM：具有宇宙学演化暗物质晕的孤立星系模拟 I. 方法与验证
Nexus-CDM: Isolated Galaxy Simulations with Cosmologically Evolving Dark-Matter Halos I. Method and Validation
- 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）
- Lund Observatory, Division of Astrophysics, Department of Physics, Lund University（隆德大学物理系天体物理分部隆德天文台）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
提出Nexus-CDM框架，结合孤立与宇宙学模拟优势，纳入星系质量增长，验证了浅中心梯度势中恒星盘易形成的结论。
AI中文摘要：
星系演化可以用两种互补的方式进行建模。孤立模拟将单个星系置于隔离环境中，在受控的初始条件下演化，而不考虑周围的宇宙网。这种方法提供了高分辨率和计算效率，非常适合厘清特定的物理过程（如反馈和盘不稳定性）并对其进行干净地测试，但代价是忽略了环境背景、来自更大尺度结构的吸积，以及随宇宙时间滋养真实星系的层级式组装。相比之下，宇宙学模拟在膨胀的宇宙中自洽地形成星系，捕捉大尺度结构形成、并合、气体流入以及潮汐剥离和冲压压力等环境效应。这种真实性带来了高昂的计算成本，需要更粗的分辨率或简化的亚网格物理来处理恒星形成和反馈。在这里，我们探索了一种结合两种方法相对优势的新范式——我们称之为Nexus-CDM框架。这种方法自然地包含了星系质量增长，而这在现有的孤立模拟中是缺失的，从而强化了星系形成和演化研究中使用的静态晕模型的局限性。该框架的可行性在一个理想化设置中得到验证，它成功再现了真实恒星盘的形成和后续演化。我们展示了一些早期结果，特别是，盘在具有浅中心梯度的引力势中容易形成，这与最近的声称相反。
英文摘要：
Galaxy evolution can be modelled in two complementary ways. Standalone simulations place a single galaxy in isolation, evolving it under controlled initial conditions without the surrounding cosmic web. This approach offers high resolution and computational efficiency, making it well suited to disentangle specific physical processes (e.g. feedback and disc instabilities) and testing them cleanly, though at the cost of ignoring environmental context, gas accretion from the broader large-scale structure, and the hierarchical assembly that feeds real galaxies over cosmic time. Cosmological simulations, by contrast, form galaxies self-consistently within an expanding universe, capturing large-scale structure formation, mergers, gas inflows, and environmental effects such as tidal stripping and ram-pressure. This realism comes at a steep computational cost, requiring coarser resolution or simplified sub-grid physics for star formation and feedback. Here, we explore a new paradigm that combines the relative merits of both methods -- what we call the Nexus-CDM framework. This approach naturally incorporates galaxy mass growth, which is absent from existing standalone simulations, reinforcing the limitations of static halo models used in galaxy formation and evolution research. The viability of the framework is demonstrated in an idealised setup, where it successfully reproduces the formation and subsequent evolution of a realistic stellar disc. We present some early results, in particular, discs form readily in a gravitational potential with a shallow central gradient, contrary to recent claims.
