Far-infrared detection of methylene

被引：38

作者：

Polehampton, ET

Menten, KM

Brünken, S

Winnewisser, G

Baluteau, JP

机构：

[1] Max Planck Inst Radioastron, D-53121 Bonn, Germany

[2] Univ Cologne, Inst Phys, D-50937 Cologne, Germany

[3] CNRS, Lab Astrophys Marseille, F-13376 Marseille 12, France

[4] Univ Aix Marseille 1, F-13376 Marseille 12, France

来源：

ASTRONOMY & ASTROPHYSICS | 2005年 / 431卷 / 01期

关键词：

infrared : ISM; ISM : molecules; molecular data ISM : individual objects : Sagittarius B2; ISM : individual objects : W49;

D O I：

10.1051/0004-6361:20041598

中图分类号：

P1 [天文学];

学科分类号：

0704 ;

摘要：

We present a clear detection of CH2 in absorption towards the molecular cloud complexes Sagittarius B2 and W49 N using the ISO Long Wavelength Spectrometer. These observations represent the first detection of its low excitation rotational lines in the interstellar medium. Towards Sagittarius B2, we detect both ortho and para transitions allowing a determination of the total CH2 column density of N(CH2) = (7.5 +/- 1.1) x 10(14) cm(-2). We compare this with the related molecule, CH2 to determine [CH/CH2] = 2.7 +/- 0.5. Comparison with chemical models shows that the CH abundance along the line of sight is consistent with diffuse cloud conditions and that the high [CH/CH2] ratio can be explained by including the effect of grain-surface reactions.

引用

页码：203 / 213

页数：11

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