Cold electrons at comet 67P/Churyumov-Gerasimenko I. A. D. Engelhardt, A. I. Eriksson, E. Vigren, X. Valliéres, M. Rubin, N. Gilet and P. Henri A&A, 616 (2018) A51 Published online: 14 August 2018 DOI: 10.1051/0004-6361/201833251