晚型矮星系的自转曲线形状
The rotation curves shapes of late-type dwarf galaxies
摘要：
我们目前的旋转曲线得出的样本62晚型矮星系已被观察到的螺旋和不规则星系（WHISP）项目的一部分韦斯特博克HI调查。通过交互式拟合模型数据立方体的观察立方体，考虑旋转曲线的形状，HI分布，倾斜度，和光束的大小来获得旋转曲线。这使得可以校正光束拖尾效应。在我们的样本中，矮星系的旋转曲线形状与晚型螺旋星系的旋转曲线形状相似，在某种意义上，它们的旋转曲线，当以盘尺度长度为单位表示时，在内部部分急剧上升，并在两个盘尺度长度处开始变平。在我们的样本中，没有一个星系的固体旋转曲线超过三个尺度长度。晚型矮星系和旋涡星系的对数外旋曲线斜率相似。因此，是否达到旋转曲线的平坦部分似乎更多地取决于旋转曲线的范围而不是其幅度。我们还发现外旋曲线形状对光度的依赖性不强，至少对于比M_R~-19暗的星系是这样。我们发现，在旋涡星系和晚型矮星系的中心区域，光的中心分布的形状和旋转曲线的内部上升是相关的。这意味着中心光密度较强的星系也有较高的中心质量密度，这表明即使在低表面亮度的矮星系中，发光质量也主导了中心区域的引力势。
英文摘要：
We present rotation curves derived for a sample of 62 late-type dwarf galaxies that have been observed as part of the Westerbork HI Survey of Spiral and Irregular Galaxies (WHISP) project. The rotation curves were derived by interactively fitting model data cubes to the observed cubes, taking rotation curve shape, HI distribution, inclination, and the size of the beam into account. This makes it possible to correct for the effects of beam smearing. The dwarf galaxies in our sample have rotation-curve shapes that are similar to those of late-type spiral galaxies, in the sense that their rotation curves, when expressed in units of disk scale lengths, rise as steeply in the inner parts and start to flatten at two disk scale lengths. None of the galaxies in our sample have solid-body rotation curves that extend beyond three scale lengths. The logarithmic outer rotation curve slopes are similar between late-type dwarf and spiral galaxies. Thus, whether the flat part of the rotation curve is reached seems to depend more on the extent of the rotation curve than on its amplitude. We also find that the outer rotation curve shape does not strongly depend on luminosity, at least for galaxies fainter than M_R~-19. We find that in spiral galaxies and in the central regions of late-type dwarf galaxies, the shape of the central distribution of light and the inner rise of the rotation curve are related. This implies that galaxies with stronger central concentrations of light also have higher central mass densities, and it suggests that the luminous mass dominates the gravitational potential in the central regions, even in low surface brightness dwarf galaxies.
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