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arXiv 0811.0859astro-ph
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银河系的统一自转曲线--分解为de Vaucouleurs膨胀、盘、暗晕和9 kpc自转倾角

Unified Rotation Curve of the Galaxy -- Decomposition into de Vaucouleurs Bulge, Disk, Dark Halo, and the 9-kpc Rotation Dip --

Y. Sofue, M. Honma, T. Omodaka

摘要:

本文通过对银河系常数R_0=8 kpc和V_0=200 km/s的距离和速度的重新计算,给出了一条由现有数据重建的银河系统一自转曲线。我们将其分解为一个具有德沃库勒定律轮廓的凸起,其半质量尺度半径为0.5 kpc,质量为1.8 x 10^{10} M_{sun},一个尺度半径为3.5 kpc,6.5 x 10^{10} M_{sun}的指数盘,以及一个终极速度为200 km/s的等温暗晕。银河系的自转曲线首次获得了r^{1/4}定律拟合。在拟合这些基本结构后,两个局部极小值,或倾角,旋转速度是突出的半径3和9千秒差距。3千秒差距的倾角与观测到的沙洲一致。另一种解释是,它是一个密度最大的大质量环,半径为4kpc。9千秒差距的倾角是银河系自转曲线中最奇特的特征。我们解释它由一个大规模的环的振幅高达0.3至0.4倍的磁盘密度与密度峰值在半径11千秒差距。这个巨大的环可能与英仙座的旋臂有关,但没有HI气体的特殊特征。

英文摘要:

We present a unified rotation curve of the Galaxy re-constructed from the existing data by re-calculating the distances and velocities for a set of galactic constants R_0=8 kpc and V_0=200 km/s. We decompose it into a bulge with de Vaucouleurs-law profile of half-mass scale radius 0.5 kpc and mass 1.8 x 10^{10}M_{sun}, an exponential disk of scale radius 3.5 kpc of 6.5 x 10^{10}M_{sun}, and an isothermal dark halo of terminal velocity 200 km/s. The r^{1/4}-law fit was obtained for the first time for the Milky Way's rotation curve. After fitting by these fundamental structures, two local minima, or the dips, of rotation velocity are prominent at radii 3 and 9 kpc. The 3-kpc dip is consistent with the observed bar. It is alternatively explained by a massive ring with the density maximum at radius 4 kpc. The 9-kpc dip is clearly exhibited as the most peculiar feature in the galactic rotation curve. We explain it by a massive ring of amplitude as large as 0.3 to 0.4 times the disk density with the density peak at radius 11 kpc. This great ring may be related to the Perseus arm, while no peculiar feature of HI-gas is associated.

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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