[12Cii] and [13C ii] 158 μm emission from NGC 2024: Large column densities of ionized carbon U. U. Graf, R. Simon, J. Stutzki, S. W. J. Colgan, X. Guan, R. Güsten, P. Hartogh, C. E. Honingh and H.-W. Hübers A&A, 542 (2012) L16 Published online: 10 May 2012 DOI: 10.1051/0004-6361/201218930