赫歇尔望远镜对特殊源的观测：利用CH吸收线探测旋臂云
星系天体物理
2015-05-19 v1
摘要
我们利用赫歇尔空间天文台/HIFI仪器，观测了连续谱源Sgr~B2(M)方向的CH吸收线（）。借助HIFI提供的高光谱分辨率和宽速度覆盖范围，我们探测并识别出31个具有不同径向速度和线宽的CH吸收特征。线宽较窄、柱密度较低的云显示出“旋臂”云特征，而线宽最宽、柱密度最高的吸收成分则对应于来自Sgr~B2包层的气体。观测表明，每条“旋臂”都包含多个速度成分，说明这些云并非均匀，而是具有内部结构。这条几乎贯穿整个银河系的视线路径，为研究弥漫云中简单分子的基础化学提供了独特机会，因为多种不同类型的云被同时采样。我们发现，紫外观测在较低下得到的CH与H柱密度之间的线性关系，在更高的视觉消光范围内不再成立。在该范围内，曲线趋于平缓，这可能意味着CH在这些云的致密核中被消耗。
引用
@article{arxiv.1007.1867,
title = {Herschel observations of extra-ordinary sources: Detecting spiral arm clouds by CH absorption lines},
author = {S. -L. Qin and P. Schilke and C. Comito and T. Möller and R. Rolffs and H. S. P. Müller and A. Belloche and K. M. Menten and D. C. Lis and T. G. Phillips and E. A. Bergin and T. A. Bell and N. R. Crockett and G. A. Blake and S. Cabrit and E. Caux and C. Ceccarelli and J. Cernicharo and F. Daniel and M. -L. Dubernet and M. Emprechtinger and P. Encrenaz and E. Falgarone and M. Gerin and T. F. Giesen and J. R. Goicoechea and P. F. Goldsmith and H. Gupta and E. Herbst and C. Joblin and D. Johnstone and W. D. Langer and S. D. Lord and S. Maret and P. G. Martin and G. J. Melnick and P. Morris and J. A. Murphy and D. A. Neufeld and V. Ossenkopf and L. Pagani and J. C. Pearson and M. Pérault and R. Plume and M. Salez and S. Schlemmer and J. Stutzki and N. Trappe and F. F. S. van der Tak and C. Vastel and S. Wang and H. W. Yorke and S. Yu and J. Zmuidzinas and A. Boogert and R. Güsten and P. Hartogh and N. Honingh and A. Karpov and J. Kooi and J. M. Krieg and R. Schieder and M. C. Diez-Gonzalez and R. Bachille and J. Martin-Pintado and W. Baechtold and M. Olberg and L. H. Nordh and J. L. Gill and G. Chattopadhyay},
journal= {arXiv preprint arXiv:1007.1867},
year = {2015}
}
备注
Accepted for publication in A&A, HIFI Special Issue