Swaters RA, Madore BF, Trewhella M
Astrophys J. 2000 Mar 10;531(2):L107-L110. doi: 10.1086/312540.
High-resolution Halpha rotation curves are presented for five low surface brightness galaxies. These Halpha rotation curves have shapes different from those previously derived from H i observations, probably because of the higher spatial resolution of the Halpha observations. The Halpha rotation curves rise more steeply in the inner parts than the H i rotation curves, and they reach a flat part beyond about two disk scale lengths. With radii expressed in optical disk scale lengths, the rotation curves of the low surface brightness galaxies presented here and those of the high surface brightness galaxies have almost identical shapes. Mass modeling shows that the contribution of the stellar component to the rotation curves may be scaled to explain most of the inner parts of the rotation curves, albeit with high stellar mass-to-light ratios. On the other hand, well-fitting mass models can also be obtained with lower contributions of the stellar disk. These observations suggest that the luminous mass density and the total mass density are coupled in the inner parts of these galaxies.
给出了五个低表面亮度星系的高分辨率Hα旋转曲线。这些Hα旋转曲线的形状与先前从氢Ⅰ观测得出的曲线不同，这可能是由于Hα观测具有更高的空间分辨率。Hα旋转曲线在内区比氢Ⅰ旋转曲线上升得更陡，并且在超过大约两个盘尺度长度之外达到一个平坦部分。以光学盘尺度长度表示半径时，这里给出的低表面亮度星系的旋转曲线与高表面亮度星系的旋转曲线具有几乎相同的形状。质量建模表明，恒星成分对旋转曲线的贡献可以进行缩放以解释旋转曲线的大部分内区，尽管恒星质量与光度比很高。另一方面，在恒星盘贡献较低的情况下也可以得到拟合良好的质量模型。这些观测结果表明，在这些星系的内区，发光质量密度和总质量密度是相互关联的。
