Cold gas in the Perseus cluster core: excitation of molecular gas in filaments P. Salomé, F. Combes, Y. Revaz, A. C. Edge, N. A. Hatch, A. C. Fabian and R. M. Johnstone A&A, 484 2 (2008) 317-325 Published online: 16 April 2008 DOI: 10.1051/0004-6361:200809493