arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1802.09291astro-ph.GA
收藏

利用TGASxRAVE中的红团星计算太阳邻域中的垂直力--对局部暗物质密度的约束

The vertical force in the Solar Neighbourhood using red clump stars in TGASxRAVE - Constraints on the local dark matter density

Jorrit H. J. Hagen, Amina Helmi

备注：
9 pages, 10 figures. Submitted to A&A
发表信息：
A&A 615, A99 (2018)
阅读 PDF
arXiv 页面 ↗HTML 原文 ↗

摘要：

我们结合TGAS和RAVE的数据来约束局部暗物质密度，研究了太阳邻域内红团簇星的运动学。在标定了红团簇星的绝对星等之后，我们描述了它们在$6$ - $10$ kpc径向距离范围内以及距银道面$1.5$ kpc径向距离范围内的速度分布。然后，我们应用轴对称的Jeans方程的子集代表薄和厚磁盘，以确定（本地）分布的质量附近的磁盘我们的银河系。我们的运动学地图表现良好，允许一个简单的本地确定的垂直力，我们发现这是$K_z^{\rm thin} = -2454 \pm 619$和$K_z^{\rm thick} = -2141 \pm 774$ $(\mathrm{km/s})^2 \! /\mathrm{kpc}$在$1.5$千秒差距远离银河系平面的薄和厚盘样品和薄和厚盘尺度高度分别为0.28千秒差距和1.12千秒差距。这些测量值可以转化为局部暗物质密度$ρ_\textrm{DM} \sim 0.018 \pm 0.002 M_\odot/\textrm{pc}^3$。该估计值的系统误差远大于引用的统计误差，因为即使薄圆盘的刻度高度相差10%，也会导致$ρ_\textrm{DM}$值变化30%，并且与数据的拟合几乎同样良好。

英文摘要：

We investigate the kinematics of red clump stars in the Solar Neighbourhood by combining data from TGAS and RAVE to constrain the local dark matter density. After calibrating the absolute magnitude of red clump stars, we characterize their velocity distribution over a radial distance range of $6$-$10$ kpc and up to $1.5$ kpc away from the Galactic plane. We then apply the axisymmetric Jeans equations on subsets representing the thin and thick disks to determine the (local) distribution of mass near the disk of our Galaxy. Our kinematic maps are well-behaved permitting a straightforward local determination of the vertical force, which we find to be $K_z^{\rm thin} = -2454 \pm 619$ and $K_z^{\rm thick} = -2141 \pm 774$ $(\mathrm{km/s})^2 \! /\mathrm{kpc}$ at $1.5$ kpc away from the Galactic plane for the thin and thick disk samples and for thin and thick disk scale heights of 0.28 kpc and 1.12 kpc respectively. These measurements can be translated into a local dark matter density $ρ_\textrm{DM} \sim 0.018 \pm 0.002 M_\odot/\textrm{pc}^3$. The systematic error on this estimate is much larger than the quoted statistical error, since even a 10% difference in the scale height of the thin disk leads to a 30% change in the value of $ρ_\textrm{DM}$, and a nearly equally good fit to the data.

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。

↑