Hunting for the elusive methylene radical A. M. Jacob, K. M. Menten, Y. Gong, P. Bergman, M. Tiwari, S. Brünken and A. O. H. Olofsson A&A, 647 (2021) A42 Published online: 04 March 2021 DOI: 10.1051/0004-6361/202039906