High-Resolution 13CO and C 18O J = 1--0 Observations of NGC 1068: Molecular Gas Properties and a High C 18O/ 13CO Intensity Ratio
Abstract
We present high-resolution (~5"-6") aperture synthesis observations of ^13^CO and C^18^O J = 1-0 lines in the prototypical Seyfert 2 galaxy NGC 1068. The line ratio Snu_(^12^CO)/Snu_(^13^CO) varies significantly along the ring, indicating optical depth variations. We also find a high average line ratio <R>=<Snu_(C^18^O)/Snu_(^13C^O) > = 0.3, which is almost twice the highest value in our own galaxy. This is also one of the highest values reported to date for an extragalactic source and the first such measurement for Seyfert galaxies. We argue that such a high value could be the result of optical depth effects and/or an intrinsically high [C^18^O/^13^CO] abundance.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- July 1996
- DOI:
- 10.1086/177410
- Bibcode:
- 1996ApJ...465..173P
- Keywords:
-
- GALAXIES: INDIVIDUAL NGC NUMBER: NGC 1068;
- GALAXIES: ABUNDANCES;
- GALAXIES: ISM;
- GALAXIES: SEYFERT