Protonated hydrogen cyanide as a tracer of pristine molecular gas Y. Gong, F. J. Du, C. Henkel, A. M. Jacob, A. Belloche, J. Z. Wang, K. M. Menten, W. Yang, D. H. Quan, C. T. Bop et al. (4 more) A&A, 679 (2023) A39 Published online: 01 November 2023 DOI: 10.1051/0004-6361/202347409