Excitation of interstellar methylamine.
Abstract
Results are presented for observations of the a-type 2(02)-1(01) transition of CH3NH2 (88.67 GHz) in the interstellar cloud Sgr B2. The frequencies of the 2(02)-1(01) lines were measured in the laboratory, and the observations were carried out using the NRAO 11-m telescope at Kitt Peak. The observed line intensity is shown to confirm the anomalously large population of the 2(02) level suggested by Fourikis et al. (1974). Collisional excitation of CH3NH2 is analyzed, and it is concluded that CH3NH2 molecules in Sgr B2 are excited by collision with hydrogen molecules at particle densities of about 10,000 per cu cm. The intensity of the a-type 2(02)-1(10) transition is shown to be significantly increased by collision-pumped maser action.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- June 1975
- DOI:
- 10.1086/181818
- Bibcode:
- 1975ApJ...198L..85K
- Keywords:
-
- Amines;
- Interstellar Gas;
- Methyl Compounds;
- Molecular Excitation;
- Brightness Temperature;
- Microwave Emission;
- Molecular Spectra;
- Population Theory;
- Transition Probabilities;
- Astrophysics