The cosmic-ray ionisation rate in the pre-stellar core L1544 E. Redaelli, O. Sipilä, M. Padovani, P. Caselli, D. Galli and A. V. Ivlev A&A, 656 (2021) A109 Published online: 10 December 2021 DOI: 10.1051/0004-6361/202141776