Dynamical Mass Estimates for the Halo of M31 from Keck Spectroscopy
Dynamical Mass Estimates for the Halo of M31 from Keck Spectroscopy
复制标题
根据凯克光谱对 M31 光晕的动态质量估计
DOI：
10.1086/312861
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发表时间：
2000
期刊：
影响因子：
--
通讯作者：
S. Vogt
中科院分区：
文献类型：
--
作者：
N. Evans;M. Wilkinson;P. Guhathakurta;E. Grebel;S. Vogt
在过去的几个月里，使用凯克望远镜上的光谱仪(HIRES和LRIS)测量了仙女座星系(M31)的所有矮球状伴星的径向速度。这封信总结了所有伴星系的径向速度和距离的数据，并提出了新的动力学模型来估计M31扩展晕的质量。根据建模细节的不同，M31总质量的最佳拟合值为~(7-10)×1011M☉。由于数据集的小，质量估计伴随着相当大的不确定性；例如，总质量的上限为~24×1011M☉，而下限为~3×1011M☉。这些数值比最新估计的最有可能的银河系晕质量要小。考虑到所有的不确定性，一个公平的结论是，M31晕的质量大致与银河晕一样大。没有动力学证据支持人们普遍认为M31质量更大的观点--它甚至可能没有那么大。
The last few months have seen the measurements of the radial velocities of all of the dwarf spheroidal companions to the Andromeda galaxy (M31) using the spectrographs (HIRES and LRIS) on the Keck Telescope. This Letter summarizes the data on the radial velocities and distances for all the companion galaxies and presents new dynamical modeling to estimate the mass of the extended halo of M31. The best-fit values for the total mass of M31 are ~(7-10) × 1011 M☉, depending on the details of the modeling. The mass estimate is accompanied by considerable uncertainty caused by the small size of the data set; for example, the upper bound on the total mass is ~24 × 1011 M☉, while the lower bound is ~3 × 1011 M☉. These values are less than the most recent estimates of the most likely mass of the Milky Way halo. Bearing in mind all the uncertainties, a fair conclusion is that the M31 halo is roughly as massive as that of the Milky Way halo. There is no dynamical evidence for the widely held belief that M31 is more massive—it may even be less massive.