A constant N${}_2$H${}^{+}$(1-0)-to-HCN(1-0) ratio on kiloparsec scales

M. J. Jiménez-Donaire, A. Usero, I. Bešlić +24

Nitrogen hydrides such as NH${}_3$ and N${}_2$H${}^{+}$ are widely used by Galactic observers to trace the cold dense regions of the interstellar medium. In external galaxies, because of l…