The effects of dissipation on the gas response to oval distortions of disk galaxies
The effects of dissipation on the gas response to oval distortions of disk galaxies
复制标题
耗散对盘状星系椭圆形畸变气体响应的影响
DOI：
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发表时间：
1977
期刊：
影响因子：
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通讯作者：
R. Sanders
中科院分区：
文献类型：
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作者：
R. Sanders
非相互作用的测试粒子系综的时间依赖性的响应，一个现实的轴对称星系盘的旋转椭圆形失真的数值计算的失真角速度的几个假设值。测试粒子的响应被发现是棒状的，并强烈加强施加的扰动，如果角速度的扭曲只允许一个内部Lindblad共振。然后重复计算，每个粒子的质量分布在某个足够大的体积上。在这样的表示中，测试颗粒变成拉格朗日意义上的流体元素，并且可以以通常的方式定义人工粘度。如果这种体积粘度是唯一考虑的气体动力学效应，则“气体”通过在内部共振和共振之外的拖尾螺旋密度波内形成材料条来响应旋转椭圆形扭曲。只有人为粘性所提供的耗散，才能将恒星的棒响应与气体响应的棒加螺旋密度波区分开来。
The time-dependent response of a ensemble of noninteracting test particles to a rotating oval distortion of a realistic axisymmetric galactic disk is numerically calculated for several assumed values of the distortion angular velocity. The test-particle response is found to be barlike and to strongly reinforce the imposed perturbation if the angular velocity of the distortion permits only one inner Lindblad resonance. The calculations are then repeated, with the mass of each particle distributed over some sufficiently large volume. In such a representation, the test particles become fluid elements in a Lagrangian sense, and an artificial viscosity may be defined in the usual manner. If this bulk viscosity is the only gas dynamical effect considered, the 'gas' responds to the rotating oval distortion by forming a material bar inside the inner resonance and trailing spiral density waves beyond the resonance. It is only the dissipation provided by the artificial viscosity which distinguishes the bar response of the stars from the bar-plus-spiral-density waves of the gas response.