Ionization toward the high-mass star-forming region NGC 6334 I Jorge L. Morales Ortiz, Cecilia Ceccarelli, Dariusz C. Lis, Luca Olmi, René Plume and Peter Schilke A&A, 563 (2014) A127 Published online: 20 March 2014 DOI: 10.1051/0004-6361/201322071