标题： 使用数值N体模拟估计棒旋星系中的非圆运动 显示英文标题

标题： Estimating non-circular motions in barred galaxies using numerical N-body simulations

摘要： 观测到的棒旋星系中气体的速度是方位平均圆周速度和非圆运动的组合，主要是由于气体沿着棒状结构流动引起的。 在将观测到的速度用于质量建模之前，必须考虑这些非圆运动。 在本工作中，我们使用模拟数据检查了倾斜环方法和DiskFit算法在将棒旋星系的速度图转换为旋转曲线（RCs）方面的性能。 我们发现，不考虑流体运动的倾斜环方法，在棒与投影主轴平行或垂直时，会低估或高估圆周运动。 包含流体运动的DiskFit方法仅适用于棒与图像主轴或次轴不对齐的情况。 因此，我们提出了一种基于星系数值模拟的旋转曲线校正方法。 我们根据具有与观测星系相似性质和投影的星系数值模拟，对来自倾斜环方法得到的旋转曲线进行校正。 以NGC 3319的观测为例，该星系的棒与主轴对齐，我们展示了未校正和校正后的旋转曲线推导出的质量模型存在显著差异。 这些结果表明校正非圆运动的重要性，并证明了需要新的方法来考虑这些运动，因为当前的方法在特定棒对齐情况下失效。 显示英文摘要

摘要： The observed velocities of the gas in barred galaxies are a combination of the azimuthally-averaged circular velocity and non-circular motions, primarily caused by gas streaming along the bar. These non-circular flows must be accounted for before the observed velocities can be used in mass modeling. In this work, we examine the performance of the tilted-ring method and the DiskFit algorithm for transforming velocity maps of barred spiral galaxies into rotation curves (RCs) using simulated data. We find that the tilted-ring method, which does not account for streaming motions, under/over-estimates the circular motions when the bar is parallel/perpendicular to the projected major axis. DiskFit, which does include streaming motions, is limited to orientations where the bar is not-aligned with either the major or minor axis of the image. Therefore, we propose a method of correcting RCs based on numerical simulations of galaxies. We correct the RC derived from the tilted-ring method based on a numerical simulation of a galaxy with similar properties and projections as the observed galaxy. Using observations of NGC 3319, which has a bar aligned with the major axis, as a test case, we show that the inferred mass models from the uncorrected and corrected RCs are significantly different. These results show the importance of correcting for the non-circular motions and demonstrate that new methods of accounting for these motions are necessary as current methods fail for specific bar alignments.