We report the detection of small scale bending waves, also known as corrugations, in the dust lanes of five nearby edge-on disc galaxies. This phenomenon, where the disc mid-plane bends to become wavy, just as in warps but on a smaller scale, is seen here for the first time, in the dust lanes running across the discs. Because they are seen in absorption, this feature must be present in the dust disc in the outskirts of these galaxies. We enhance the visibility of these features using unsharp masking, trace the dust mid-plane across the disc, measure the corrugation amplitude by eye and the corrugation wavelength using Fourier analysis. The corrugation amplitude is found to be in the range of 70 - 200 pc and the wavelengths lie between 1 - 5 kpc. In this limited sample, we find that the amplitude of the corrugations tends to be larger for lower mass galaxies, whereas the wavelength of corrugation does not seem to depend on the mass of host galaxies. Linear stability analysis is performed to find out the dynamical state of these dust discs. Based on WKB analysis, we find that the dust corrugations in about half of our sample are stable. Further analysis, on a larger sample would be useful to strengthen the above results.

中文翻译：

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摇晃的圆盘——在边缘星系的尘埃带中看到的波纹

我们报告了在附近五个边缘盘状星系的尘埃带中检测到小尺度弯曲波，也称为波纹。这种现象，盘中平面弯曲成波浪状，就像经线一样，但规模较小，在这里第一次出现在穿过盘的尘埃带中。因为它们是在吸收中看到的，所以这个特征必须存在于这些星系外围的尘埃盘中。我们使用非锐化掩蔽来增强这些特征的可见性，在光盘上追踪灰尘中平面，通过肉眼测量波纹幅度，并使用傅立叶分析测量波纹波长。发现波纹幅度在 70 - 200 pc 范围内，波长在 1 - 5 kpc 之间。在这个有限的样本中，我们发现，对于质量较小的星系，波纹的幅度往往更大，而波纹的波长似乎并不取决于主星系的质量。进行线性稳定性分析以找出这些尘盘的动态状态。根据 WKB 分析，我们发现大约一半样本中的灰尘波纹是稳定的。进一步分析，在更大的样本上将有助于加强上述结果。