Satellite galaxies as better tracers of the Milky Way halo mass
Satellite galaxies as better tracers of the Milky Way halo mass
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DOI：
10.1017/s1743921319008020
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发表时间：
2019-06
期刊：
影响因子：
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通讯作者：
Jiaxin Han;Wenting Wang;Zhaozhou Li
中科院分区：
文献类型：
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作者：
Jiaxin Han;Wenting Wang;Zhaozhou Li
银河系晕质量的推断需要对动态示踪剂的相空间结构进行建模，不同示踪剂采用不同的模型，对晕质量的灵敏度也不同。对于稳态模型，示踪剂分布偏离稳态会导致不可约的随机偏差。这种偏差对于卫星星系和暗物质粒子来说很小，但对于晕星来说却大到2倍。这与卫星星系密切追踪暗物质粒子的基本相空间分布的图像是一致的，而晕星的相混合较少。因此，仅使用约100个卫星星系就可以获得比使用更大的晕星样本更高的精度。
Abstract The inference of the Milky Way halo mass requires modelling the phase space structure of dynamical tracers, with different tracers following different models and having different levels of sensitivity to the halo mass. For steady-state models, deviations from steady-state in the tracer distribution lead to an irreducible stochastic bias. This bias is small for satellite galaxies and dark matter particles, but as large as a factor of 2 for halo stars. This is consistent with the picture that satellite galaxies closely trace the underlying phase space distribution of dark matter particles, while halo stars are less phase-mixed. As a result, the use of only ~100 satellite galaxies can achieve a significantly higher accuracy than that achievable with a much larger sample of halo stars.