Properties of simulated Milky Way-mass galaxies in loose group and field environments
Properties of simulated Milky Way-mass galaxies in loose group and field environments
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DOI：
10.1051/0004-6361/201219649
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发表时间：
2012-10
影响因子：
6.5
通讯作者：
C. G. Few;Bradley K Gibson;Bradley K Gibson;Bradley K Gibson;S. Courty;L. Michel-Dansac;C. Brook;G. Stinson
中科院分区：
文献类型：
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作者：
C. G. Few;Bradley K Gibson;Bradley K Gibson;Bradley K Gibson;S. Courty;L. Michel-Dansac;C. Brook;G. Stinson
目标。我们测试的有效性比较模拟场盘星系的经验性质的系统内的环境更可比松散的团体，包括银河系的本地集团。方法.银河系质量的星系的宇宙学模拟已经实现了在两个不同的环境样本：在外地和松散的集团环境中具有类似的属性的本地集团。除了星系的不同环境外，样品尽可能保持均匀，在最后一次主要合并时间，晕质量和晕自旋方面具有相同的范围。这两个样本的比较允许识别模拟中的系统差异。一个运动学分解客观地量化的球体盘比，并隔离盘星人口。金属丰度梯度，磁盘规模的长度，颜色，大小和年龄-速度色散关系的研究，为每个星系的套件和这些和环境的星系之间的联系的强度进行了研究。结果金属丰度梯度与螺旋星系中HII区域的观测结果一致，并且与观测结果一致，与星系总质量相关。星系的膨胀盘比表明，这些星系是较少的球状主导比许多其他的模拟星系在文献中与大多数的两个样本被磁盘为主。我们发现，长期的演变和合并占主导地位的传播形态和金属丰度梯度没有明显的差异，两个环境样本。与这两个样本的一致性相反，有初步的证据表明，在不同的环境中，星系的速度色散-年龄关系存在系统性差异。松散的星系团的速度色散年龄关系似乎有更多的离散步骤，如果这是真的，这表明脉冲加热是更有效的星系的恒星在致密的环境比在外地。我们的结论是，在目前的分辨率的宇宙学星系模拟场环境星系是足够相似的那些松散的群体是可以接受的代理比较与银河系提供了一个类似的组装历史被认为是。
Aims. We test the validity of comparing simulated field disk galaxies with the empirical properties of systems situated within environments more comparable to loose groups, including the Milky Way’s Local Group. Methods. Cosmological simulations of Milky Way-mass galaxies have been realised in two different environment samples: in the field and in loose groups environments with similar properties to the Local Group. Apart from the differing environments of the galaxies, the samples are kept as homogeneous as possible with equivalent ranges in last major merger time, halo mass and halo spin. Comparison of these two samples allow for systematic differences in the simulations to be identified. A kinematic decomposition is employed to objectively quantify the spheroid-to-disk ratio and to isolate the disk-star population. Metallicity gradients, disk scale lengths, colours, magnitudes and age-velocity dispersion relations are studied for each galaxy in the suite and the strength of the link between these and environment of the galaxies is studied. Results. Metallicity gradients are consistent with observations of HII regions in spiral galaxies and, in agreement with observations, correlate with total galaxy mass. The bulge-to-disk ratio of the galaxies show that these galaxies are less spheroid dominated than many other simulated galaxies in literature with the majority of both samples being disk dominated. We find that secular evolution and mergers dominate the spread of morphologies and metallicity gradients with no visible differences between the two environment samples. In contrast with this consistency in the two samples there is tentative evidence for a systematic difference in the velocity dispersion-age relations of galaxies in the different environments. Loose group galaxies appear to have more discrete steps in their velocity dispersion-age relations, if this is true it suggests that impulsive heating is more efficient in the stars of galaxies in denser environment than in the field. We conclude that at the current resolution of cosmological galaxy simulations field environment galaxies are sufficiently similar to those in loose groups to be acceptable proxies for comparison with the Milky Way provided that a similar assembly history is considered.