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arXiv 1409.1797astro-ph.GA
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Local Group的运动中心和质量分布

The kinematical center and mass profile of the Local Group

Alan B. Whiting

摘要:

放弃光跟踪质量的假设,我寻求本星系群的中心的位置完全基于运动学数据和合理的假设。现有的一组位置和径向速度被证明是一个误导性的指标,当地集团的运动,给一个方向的中心偏移从真正的一个,统计技术的适度复杂不赶上偏移。修正后的计算表明,中心位于M31方向,在方法的不确定性范围内,几度。到中心的距离还没有很好的确定,距离银河系约0.5 Mpc。观测到的(银河系中心)径向速度的模式排除了动力学上重要的“孤儿晕”和整个星系群的任何扩展的暗物质晕,并表明星系群是从一个比它目前所占据的更大的体积形成的。单是动能图就表明,星团的质量有效地集中在M31和银河系中。

英文摘要:

Abandoning the assumption that light traces mass, I seek the location of the center of the Local Group of galaxies based solely on kinematic data and the plausible assumption of infall. The available set of positions and radial velocities is shown to be a misleading indicator of Local Group motions, giving a direction to the center offset from the true one; statistical techniques of moderate sophistication do not catch the offset. Corrected calculations show the center to lie in the direction to M31 within the uncertainty of the method, a few degrees. The distance to the center is not well determined, lying about 0.5 Mpc from the Milky Way. The pattern of observed (galactocentric) radial velocities excludes both dynamically important `orphan haloes' and any extended dark matter halo for the Group as a whole, and shows the Group to have formed from a much more extended volume than it presently occupies. Kinematics alone indicates that the mass of the Group is concentrated effectively in M31 and the Milky Way.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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