Study of Molecular Abundances in the Galaxy with Active Galactic Nucleus
Detections of C2H and Cyclic-C3H2 !
We used the Nobeyama 45-m telescope to conduct a spectral line survey in the 3-mm band (85.1-98.4 GHz) toward one of the nearest galaxies with active galactic nucleus NGC 1068 (M 77) and the prototypical starburst galaxy NGC 253. We detected rotational transitions of C2H, cyclic-C3H2, and H13CN in NGC 1068. These are detections of carbon-chain and carbon-ring molecules in NGC 1068.
We calculated the abundances of these molecules for both NGC 1068 and NGC 253, and found that there were no significant differences in the abundances between the two galaxies. This result suggests that the basic carbon-containing molecules are either insusceptible to AGN, or are tracing cold molecular gas rather than X-ray irradiated hot gas. (T. Nakajima, S. Takano, K. Kohno, and H. Inoue; accepted for publication in the Astrophysical Journal Letters)
- Figure: The C2H lines toward (a) NGC 1068 and (b) NGC 253, and the cyclic-C3H2 lines toward (c) NGC 1068 and (d) NGC 253. The vertical axis is conversions from intensity to temperature and the horizontal axis is velocity. The C2H line consists of 6 hyperfine components and we detected two fine structure components because of the line blending.
