A dynamical study of the Ursa Minor dwarf spheroidal galaxy
A dynamical study of the Ursa Minor dwarf spheroidal galaxy
复制标题
小熊座矮椭球星系的动力学研究
DOI：
10.1093/mnras/271.3.693
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发表时间：
1994
影响因子：
4.8
通讯作者：
D. Carter
中科院分区：
文献类型：
--
作者：
J. Hargreaves;G. Gilmore;M. Irwin;D. Carter
我们已经观察到46巨星在小熊座矮球状（dSph）星系，并获得了高质量的光谱，其中35个。用最大似然法计算得到的样本速度频散为，平均速度为。有证据表明围绕长轴旋转：直线拟合，相当于固体旋转，给出了从轴每100 pc的梯度，其中正距离是到长轴的西北部。这一发现为小熊座可能被潮汐破坏的建议提供了证据。如果进一步的工作排除了这种可能性，那么，假设动力学平衡，速度色散的各向同性（当旋转被扣除时）和双星的贡献可以忽略不计，核心的质光比为，总的质光比为，这意味着存在大量的暗物质。
We have observed 46 giant stars in the Ursa Minor dwarf spheroidal (dSph) galaxy and obtained high-quality spectra for 35 of these. The velocity dispersion of the sample calculated by a maximum likelihood method isand the mean velocity is. There is evidence for rotation around the major axis: a straight line fit, equivalent to solid body rotation, gives a gradient ofper 100 pc from the axis, where the positive distances are to the north-west of the major axis. This discovery adds evidence to the suggestion that Ursa Minor may be being tidally disrupted. If further work eliminates this possibility, then, assuming dynamical equilibrium, isotropy in the velocity dispersion (which iswhen the rotation has been subtracted) and a negligible contribution from binary stars, the core mass-to-light ratio isand the total mass-to-light ratio is, implying the presence of large quantities of dark matter.