论文标题
多组分银河系磁盘的重力势能
Gravitational potential energy of a multi-component galactic disk
论文作者
论文摘要
我们从头开始计算恒星和气体的重力多组分银盘的每单位区域的重力势能，这作为在垂直密度分布，垂直重力力和垂直距离上的整合。这是基于CAMM提出的单组分磁盘提出的方法，我们在此处扩展了多组分磁盘，通过在任何半乳突半径R上明确得出能量的表达。对于自隔离的分布，密度和力是通过共同求解垂直静水平均衡和poisson均等的方程来获得的。用耦合系统获得的密度分布和力代替数值，在能量的派生表达中，我们发现每个组分的能量与相应的单分量案例的能量相比保持不变。我们通过分析组件的能量来简化上述表达来解释这一令人惊讶的结果，事实证明，该能量等于表面密度时间的平方垂直速度分散剂。但是，在耦合情况下，将单位测试质量从中间平面提高到一定高度z所需的能量。因此，该系统更紧密地靠近中间平面，因此由于外部潮汐相遇而很难干扰它。
We calculate ab initio the gravitational potential energy per unit area for a gravitationally coupled multi-component galactic disk of stars and gas, which is given as the integration over vertical density distribution, vertical gravitational force, and vertical distance. This is based on the method proposed by Camm for a single-component disk, which we extend here for a multi-component disk by deriving the expression of the energy explicitly at any galactocentric radius R. For a self-consistent distribution, the density and force are obtained by jointly solving the equation of vertical hydrostatic equilibrium and the Poisson equation. Substituting the numerical values for the density distribution and force obtained for the coupled system, in the derived expression of the energy, we find that the energy of each component remains unchanged compared to the energy for the corresponding single-component case. We explain this surprising result by simplifying the above expression for the energy of a component analytically, which turns out to be equal to the surface density times the squared vertical velocity dispersion of the component. However, the energy required to raise a unit test mass to a certain height z from the mid-plane is higher in the coupled case. The system is therefore more tightly bound closer to the mid-plane, and hence it is harder to disturb it due to an external tidal encounter.
