Optical/X-ray correlations during the V404 Cygni June 2015 outburst J. Alfonso-Garzón, C. Sánchez-Fernández, P. A. Charles, J. M. Mas-Hesse, P. Gandhi, M. Kimura, A. Domingo, J. Rodriguez and J. Chenevez A&A, 620 (2018) A110 Published online: 07 December 2018 DOI: 10.1051/0004-6361/201834102