A two-mode planetary nebula luminosity function A. Rodríguez-González, L. Hernández-Martínez, A. Esquivel, A. C. Raga, G. Stasińska, M. Peña and Y. D. Mayya A&A, 575 (2015) A1 Published online: 10 February 2015 DOI: 10.1051/0004-6361/201423713