The diffuse interstellar band around 8620 Å - I. Methods and application to the GIBS data set H. Zhao, M. Schultheis, A. Recio-Blanco, G. Kordopatis, P. de Laverny, A. Rojas-Arriagada, M. Zoccali, F. Surot and E. Valenti A&A, 645 (2021) A14 Published online: 24 December 2020 DOI: 10.1051/0004-6361/202039736