Figuring Out Gas & Galaxies in Enzo (FOGGIE). I. Resolving Simulated Circumgalactic Absorption at 2 ≤ z ≤ 2.5
Figuring Out Gas & Galaxies in Enzo (FOGGIE). I. Resolving Simulated Circumgalactic Absorption at 2 ≤ z ≤ 2.5
复制标题
DOI：
10.3847/1538-4357/ab0654
复制
发表时间：
2018-10
期刊：
影响因子：
--
通讯作者：
M. Peeples;L. Corlies;J. Tumlinson;B. O’Shea;N. Lehner;John M. O’Meara;J. Howk;N. Earl;Britton D. Smith;J. Wise;C. Hummels
中科院分区：
文献类型：
--
作者：
M. Peeples;L. Corlies;J. Tumlinson;B. O’Shea;N. Lehner;John M. O’Meara;J. Howk;N. Earl;Britton D. Smith;J. Wise;C. Hummels
我们展示了新的“找出恩佐的气体和星系”（FOGGIE）项目的模拟。大多数现有的星系形成模拟将计算资源集中在具有固定质量的流体和粒子元素的星系盘和球体上，而 FOGGIE 模拟则侧重于星系周围的环星系介质 (CGM) 的极端空间和质量分辨率。使用 Enzo 代码和新的细化方案，FOGGIE 达到了 381 共移 h−1 pc 的空间分辨率，并将中心晕的极低质量 (≲1–100 ) 解析为 100 共移 h−1 kpc。在这些分辨率下，与使用标准密度相关细化模拟的相同结构相比，产生模拟吸收的云状和丝状结构更小，分辨率也更好。大多数模拟吸收出现在可识别且分辨率良好的结构中，其质量≲104，远低于典型变焦模拟的质量分辨率。然而，随着分辨率的变化，质量表面密度和离子覆盖分数等积分量仅变化 ≲30% 的水平。即使吸收云的大小和分布发生巨大变化，预测量的这些相对较小的变化也表明常用的可观测数据对底层气体的物理结构仅提供微弱的约束。将模拟吸收特征与 KODIAQ（凯克类星体电离吸收数据库）对 z ∼ 2–3.5 莱曼极限系统的调查进行比较，我们表明高分辨率 FOGGIE 可以更好地解析检测到的吸收的内部运动结构，并更好地匹配观察到的吸收体特性的分布。这些结果表明，环星系介质分辨率是正确测试通过环星系观测进行的星系演化模拟的关键。
We present simulations from the new “Figuring Out Gas & Galaxies in Enzo” (FOGGIE) project. In contrast to most extant simulations of galaxy formation, which concentrate computational resources on galactic disks and spheroids with fluid and particle elements of fixed mass, the FOGGIE simulations focus on extreme spatial and mass resolution in the circumgalactic medium (CGM) surrounding galaxies. Using the Enzo code and a new refinement scheme, FOGGIE reaches spatial resolutions of 381 comoving h−1 pc and resolves extremely low masses (≲1–100 ) out to 100 comoving h−1 kpc from the central halo. At these resolutions, cloud and filament-like structures giving rise to simulated absorption are smaller, and better resolved, than the same structures simulated with standard density-dependent refinement. Most of the simulated absorption arises in identifiable and well-resolved structures with masses ≲104 , well below the mass resolution of typical zoom simulations. However, integrated quantities such as mass surface density and ionic covering fractions change at only the ≲30% level as resolution is varied. These relatively small changes in projected quantities—even when the sizes and distribution of absorbing clouds change dramatically—indicate that commonly used observables provide only weak constraints on the physical structure of the underlying gas. Comparing the simulated absorption features to the KODIAQ (Keck Observatory Database of Ionized Absorption toward Quasars) survey of z ∼ 2–3.5 Lyman limit systems, we show that high-resolution FOGGIE runs better resolve the internal kinematic structure of detected absorption and better match the observed distribution of absorber properties. These results indicate that circumgalactic medium resolution is key in properly testing simulations of galaxy evolution with circumgalactic observations.