On the usage of Flaring Gas Layers to determine the Shape of Dark Matter Halos
On the usage of Flaring Gas Layers to determine the Shape of Dark Matter Halos
复制标题
关于使用燃烧气体层来确定暗物质晕的形状
DOI：
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发表时间：
1995
期刊：
影响因子：
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通讯作者：
R. Olling
中科院分区：
文献类型：
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作者：
R. Olling
我提出了一种推导螺旋星系暗物质 (DM) 晕形状的新方法。该方法依赖于模型预测与气体层高光谱和空间分辨率 HI 观测的比较。
由星系的 {emtotal} 质量分布产生的势用于计算气体的垂直分布。我开发了一种新算法来计算任意方位对称密度分布的力场。该算法用于计算径向截断的恒星盘以及火炬气体层产生的力。
我使用一个简单的双参数族盘晕模型，其观测到的赤道自转曲线基本相同，但垂直力不同。该质量模型由具有恒定 M/L 的恒星盘和具有给定轴比的 DM 晕组成。我近似了气态盘产生的径向力，并迭代确定了气体全局分布产生的垂直力。
气态盘的厚度对 DM 晕的扁平化和气体的自重力敏感，但对盘晕分解的特定选择不敏感。
我表明，气体层厚度的确定不仅限于边缘星系，还可以测量中等倾斜的系统。
I present a new method of deriving the shape of the dark matter (DM) halos of spiral galaxies. The method relies on the comparison of model predictions with high spectral and spatial resolution HI observations of the gas layer.
The potential arising from the {em total} mass distribution of the galaxy is used in the calculation of the vertical distribution of the gas. I developed a new algorithm to calculate the force field of an arbitrary, azimuthally symmetric, density distribution. This algorithm is used to calculate the forces due to the radially truncated stellar disk as well as of the flaring gas layer.
I use a simple two-parameter family of disk-halo models which have essentially the same observed equatorial rotation curve but different vertical forces. This mass model is composed of a stellar disk with constant M/L, and a DM-halo with a given axial ratio. I approximate the radial force due to the gaseous disk, and iteratively determine the vertical force due to the global distribution of the gas.
The thickness of the gaseous disk is sensitive to both the flattening of the DM-halo and the self-gravity of the gas, but not to the particular choice of disk-halo decomposition.
I show that the determination of the thickness of the gas layer is not restricted to edge-on galaxies, but can be measured for moderately inclined systems as well.