Doubly 15N-substituted diazenylium: THz laboratory spectra and fractionation models L. Dore, L. Bizzocchi, E. S. Wirström, C. Degli Esposti, F. Tamassia and S. B. Charnley A&A, 604 (2017) A26 Published online: 27 July 2017 DOI: 10.1051/0004-6361/201629725