J. Wang, D. Li, P. F. Goldsmith, Z.-Y. Zhang, Y. Gao, Y. Shi, S. Li, M. Fang, J. Li, and J. Zhang
reported on
Molecular Oxygen in the Nearest QSO Mrk 231
Astrophys. J. 889, (2020) Art. No. 129.
The 1₁ − 1₀ spin-flip transition at a rest frequency of 118750.34 MHz was seen in emission with NOEMA. The authors provide arguments why the detection is quite secure. While these are certainly fine, some caution is still advised because it is only one line thus far.

Contributor(s): H. S. P. Müller; 02, 2020