论文标题
磁场对Galaxy $ NGC \; 6946 $中气体旋转的影响
Influence of Magnetic Fields on the Gas Rotation in the Galaxy $NGC\;6946$
论文作者
论文摘要
磁场可以在星系中气体结构的能量平衡和形成中发挥重要作用。然而，它们对星系旋转曲线的动态影响是充分探索的。我们研究了两个暗物质质量密度模型，ISO和通用NFW曲线，研究了$ ngc \; 6946 $的已知磁臂对其圆形气体旋转的动力学效果。我们为磁场结构使用了三维模型，将建模的旋转曲线拟合到通过$χ$平方的最小化方法与观察到的数据。 HI气体旋转曲线的形状更好地再现了，包括磁场的效果，尤其是在外部，在外部，磁场的动态效应可能变得很重要。旋转曲线中常规磁场贡献的典型幅度约为6-14 \; km s^{ - 1} $在Galaxy $ ngc \; 6946 $的外部气体磁盘中。正常磁场与观察到的圆形速度和暗物质的贡献比随着半乳半径的增加而增加。它与观察到的旋转速度的比率约为5％，在银河系外部区域的暗物质约为10％。因此，在螺旋星系的大规模动力学中，尤其是在星系的外部，大规模磁场不能完全忽略。
Magnetic fields can play an important role in the energy balance and formation of gas structures in galaxies. However, their dynamical effect on the rotation curve of galaxies is immensely unexplored. We investigate the dynamical effect of the known magnetic arms of $NGC\;6946$ on its circular gas rotation traced in HI, considering two dark matter mass density models, ISO, and the universal NFW profile. We used a three-dimensional model for the magnetic field structure to fit the modeled rotation curve to the observed data via an $χ$-squared minimization method. The shape of the HI gas rotation curve is reproduced better including the effect of the magnetic field, especially in the outer part, where the dynamical effect of the magnetic field could become important. The typical amplitude of the regular magnetic field contribution in the rotation curve is about $ 6 - 14 \; km s^{-1}$ in the outer gaseous disk of the galaxy $NGC\;6946$. The contribution ratio of the regular magnetic field to the observed circular velocity and to dark matter increases with the galactocentric radius. Its ratio to the observed rotational velocity is about five percent and to dark matter is about 10 percent in the outer regions of the galaxy $NGC\;6946$. Therefore, the large-scale magnetic fields cannot be completely ignored in the large-scale dynamics of spiral galaxies, especially in the outer parts of galaxies.
