发表机构
California Institute of Technology; The Observatories of the Carnegie Institution for Science; University of Pennsylvania; University of California, Davis; Yale University; DARK, Niels Bohr Institute, University of Copenhagen（加州理工学院; 卡内基科学研究所天文台; 宾夕法尼亚大学; 加利福尼亚大学戴维斯分校; 耶鲁大学; 哥本哈根大学尼尔斯·玻尔研究所DARK中心）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究通过对比不同粒子质量分辨率的FIRE-2模拟，发现高分辨率能产生更多、更低质量的矮星系星流，且其轨道特性与银河系观测更一致，表明分辨率影响星流形成与瓦解过程。
AI 中文摘要
宇宙学模拟使我们能够研究星系前身星流族群，从而可以与观测结果进行比较，以约束星系形成物理。先前的研究发现，FIRE中现今的星系前身星流比银河系中观测到的星流具有更大的近心点，这可能表明它们比银河系中的星流在更远的距离上发生潮汐瓦解，而那里的银河潮汐力较弱。一种可能的解释是，由于分辨率有限，它们潮汐瓦解得太快。在较低分辨率下，低质量矮星系可能更蓬松，更容易受到瓦解的影响。我们构建并比较了具有相同初始条件（m12i）但不同粒子质量分辨率（7070 $M_\odot$ 和 880 $M_\odot$）的两个FIRE-2宇宙学zoom-in模拟中的矮星系星流目录。使用相同的100个恒星粒子截断标准，较高分辨率的运行产生了更大的矮星系星流族群（22条星流对比14条），这主要是因为它解析出了质量更低的星流（低至约$10^{5}$ $M_\odot$）。两个模拟都在银河系中心距离小于50 kpc处形成星流，但较高分辨率的Triple Latte模拟在这些小半径处产生了更多的星流。我们发现，较高分辨率模拟中的矮星系开始瓦解时的近心点比较低分辨率模拟中的更小。通过交叉匹配星流候选体，我们为较低分辨率模拟中约89%的系统找到了对应体。对于在相似轨道上保持匹配的系统，较高分辨率的对应体保持完整的时间更长。较高分辨率模拟中星流的轨道特性与银河系矮星系星流族群大致一致，这与较低分辨率模拟形成对比。
英文摘要
Cosmological simulations allow us to study galaxy-progenitor stream populations, allowing comparisons with observations to constrain galaxy formation physics. Previous work found that present-day galaxy-progenitor streams in FIRE have larger pericenters than observed in the MW, which might indicate that they tidally disrupt at larger distances, where the Galactic tides are weaker, than in the MW. One possible explanation is that they tidally disrupt too quickly because of limited resolution. At lower resolution, low-mass dwarf galaxies can be puffier and more susceptible to disruption. We build and compare dwarf-galaxy stream catalogs in two FIRE-2 cosmological zoom-in simulations with identical initial conditions (m12i) but different particle mass resolution (7070 $M_\odot$ and 880 $M_\odot$). The higher-resolution run yields a larger dwarf galaxy stream population (22 streams versus 14) using the same cutoff of 100 star particles, primarily because it resolves lower-mass streams (down to $\sim10^{5}$ $M_\odot$). Both simulations form streams at galactocentric radii < 50 kpc, but the higher-resolution Triple Latte simulation produces more streams at these small radii. We find that dwarf galaxies in the higher-resolution simulation begin disrupting at smaller pericenters than in the lower-resolution simulation. By cross-matching stream candidates, we identify counterparts for $\sim$89$\%$ of the systems in the lower-resolution simulation. For matched systems that remain on similar orbits, the higher-resolution counterparts remain intact for longer. The orbital properties of streams in the higher-resolution simulation are broadly consistent with the MW dwarf-galaxy stream population, in contrast to the lower-resolution simulation.
Comments18 pages, 10 figures, submitted to ApJ
