标题： 南非大型望远镜观测到的超冷矮星的光谱 显示英文标题

标题： Optical Spectra of Ultracool Dwarfs with the Southern African Large Telescope

摘要： 讨论了81颗超冷矮星（光谱型为M7及之后）的新光谱。其中49个天体的光谱分类已有文献记载，另外32个天体是新分类的。 已知的光谱类型被用于测试一种自动分类方案，该方案主要依赖于模板拟合，并辅以针对模板光谱校准的光谱指数匹配。 尝试量化了光谱类型的不确定性，通常优于两个子类。 对于光谱类型与文献分类相差一个以上子类的天体进行了单独讨论。 基于模板拟合和光谱指数匹配的自动分类之间存在差异，这可能有助于标记具有异常光谱的天体。 除了32次首次分类外，还为之前分类的32颗矮星提供了替代分类。 已报告了已知超冷矮星双星2MASS J15200224$-$4422419的大规模（等效宽度大于130\AA ）H$\alpha$耀斑；奇怪的是，该天体似乎没有宁静发射线。 另外29个天体的非零等效宽度测量值列在文中。 显示英文摘要

摘要： New spectra of 81 ultracool dwarfs (spectral types M7 and later) are discussed. Spectral classifications of 49 objects are available in the literature, while 32 objects are newly classified. The known spectral types were used to test an automated classification scheme, which relies primarily on template fitting, supplemented by matching of spectral indices calibrated against the template spectra. An attempt was made to quantify the uncertainty in the spectral types, which is generally better than two subclasses. Objects for which spectral types differ by more than one subclass from the literature classifications are discussed individually. Discrepancies between automated classifications based on respectively template fitting and spectral index matching, may be useful for flagging objects with unusual spectra. Aside from the 32 first-time classifications, alternative classifications are presented for 32 previously classified dwarfs. Very large (equivalent width greater than 130 \AA) H$\alpha$ flares are reported for the known ultracool dwarf binary 2MASS J15200224$-$4422419; curiously, the object does not appear to have quiescent emission lines. Non-zero equivalent width measurements are listed for a further 29 objects.