Galaxy Models with Tangentially Anisotropic Velocity Distributions
Galaxy Models with Tangentially Anisotropic Velocity Distributions
复制标题
具有切向各向异性速度分布的星系模型
DOI：
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发表时间：
2005
期刊：
影响因子：
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通讯作者：
N. Evans
中科院分区：
文献类型：
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作者：
Jin H. An;Jin H. An;N. Evans
本文提供了两类灵活而简单的星系模型。这些族的许多代表都具有重要的宇宙学尖点，在小半径处密度表现为r-1、r-4/3或r-3/2。在大半径处，密度福尔斯在r-3和r-5之间下降。我们为所有模型提供了解析和各向异性分布函数。与许多现有的方法不同，我们的算法可以产生切向各向异性的速度分散在外部的部分，因此是有用的建模卫星星系和宿主星系晕的子结构的人口。作为应用，我们证明了银河系卫星星系人口的质量和各向异性之间的简并。这可能会在银河系的质量中引入一个0.03的不确定性因子，这是从卫星群的运动学推断出来的。
This paper provides two families of flexible and simple galaxy models. Many representatives of these families possess important cosmological cusps, with the density behaving like r-1, r-4/3, or r-3/2 at small radii. The density falls off between r-3 and r-5 at large radii. We provide analytic and anisotropic distribution functions for all the models. Unlike many existing methods, our algorithm can yield tangentially anisotropic velocity dispersions in the outer parts, and so is useful for modeling populations of satellite galaxies and substructure in host galaxy halos. As an application, we demonstrate the degeneracy between mass and anisotropy for the satellite galaxy population of the Milky Way. This can introduce a factor of ∼3 uncertainty in the mass of the Milky Way as inferred from the kinematics of the satellite population.