标题： 指数分布是尘埃密集星系盘的良好近似吗？ 显示英文标题

标题： Is the exponential distribution a good approximation of dusty galactic disks?

摘要： 我们研究了螺旋结构对有关尘埃星系边缘辐射转移计算的重要性。 广泛采用的指数盘模型（即恒星和尘埃在径向方向以及垂直于盘面的方向上都呈指数分布）现在正受到详细比较，与一个包括盘中恒星和尘埃螺旋结构的真实模型相比。 特别是，构建了具有对数螺旋臂的星系模型图像，使得观测所建议的方位平均盘在半径和高度上都是指数分布的。 然后，使用纯指数盘模型（即没有螺旋结构）来拟合这些模型图像的边缘视图。 结果表明，拟合后的参数与用于创建螺旋结构图像的真实值相比，仅变化几个百分点。这表明纯指数盘模型能够很好地描述星系盘，其参数的变化范围较小。 显示英文摘要

摘要： We investigate how significant the spiral structure is on calculations concerning radiative transfer in dusty spiral galaxies seen edge-on. The widely adopted exponential disk model (i.e. both the stars and the dust are distributed exponentially in the radial direction and also perpendicular to the plane of the disk) is now subject to a detailed comparison with a realistic model that includes spiral structure for the stars and the dust in the disk. In particular, model images of galaxies with logarithmic spiral arms are constructed, such that the azimuthally averaged disk is exponential in radius and in height, as the observations suggest. Then, pure exponential disk models (i.e. with no spiral structure) are used to fit the edge-on appearance of the model images. As a result, the parameters derived after the fit are compared to the real values used to create the spiral-structured images. It turns out that the plain exponential disk model is able to give a very good description of the galactic disk with its parameters varying only by a few percent from their true values.