OH emission from warm and dense gas in the Orion Bar PDR J. R. Goicoechea, C. Joblin, A. Contursi, O. Berné, J. Cernicharo, M. Gerin, J. Le Bourlot, E. A. Bergin, T. A. Bell and M. Röllig A&A, 530 (2011) L16 Published online: 25 May 2011 DOI: 10.1051/0004-6361/201116977