The excitation of NH2 in the interstellar medium - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Monthly Notices of the Royal Astronomical Society Année : 2019

The excitation of NH2 in the interstellar medium

The excitation of NH2 in the interstellar medium

Résumé

Accurate estimation of the abundance of the NH 2 radical in the interstellar medium requires accurate radiative and collisional rate coefficients. The calculation of hyperfine-resolved rate coefficients for the collisional (de-)excitation of NH 2 by both ortho-and para-H 2 are presented in this work. Hyperfine-resolved rate coefficients are calculated from pure rotational close-coupling rate coefficients using the M j randomizing approximation. Rate coefficients for temperatures ranging from 5 to 150 K were computed for all hyperfine transitions among the first 15 rotational energy levels of both ortho-and para-NH 2 in collisions with ortho-and para-H 2. The new data were then employed in radiative transfer calculations to simulate the excitation of NH 2 in typical star-forming regions such as W31C. We compared the excitation and brightness temperatures for different NH 2 transitions obtained using the new and the previously available collisional data. It is found that the new rate coefficients increase the simulated line intensities. As a consequence, NH 2 abundance derived from the observations will be significantly reduced by the use of the present rate coefficients.
Fichier principal
Vignette du fichier
NH2_H2_astro.pdf (338.53 Ko) Télécharger le fichier
Origine : Fichiers produits par l'(les) auteur(s)

Dates et versions

hal-03064773 , version 1 (14-12-2020)

Identifiants

Citer

N Bouhafs, A Bacmann, A Faure, François Lique. The excitation of NH2 in the interstellar medium. Monthly Notices of the Royal Astronomical Society, 2019, ⟨10.1093/mnras/stz2586⟩. ⟨hal-03064773⟩
49 Consultations
135 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More