Parsec scales of carbon chain and complex organic molecules in AFGL 2591 and IRAS 20126 P. Freeman, S. Bottinelli, R. Plume, E. Caux, C. Monaghan and B. Mookerjea A&A, 678 (2023) A18 Published online: 29 September 2023 DOI: 10.1051/0004-6361/202347263