Collisional Excitation of Interstellar NH, ND and CH3OCHO

Foley, Niall (2023) Collisional Excitation of Interstellar NH, ND and CH3OCHO. Bachelor's Thesis, Astronomy.

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Abstract

The excitation of molecular species under interstellar conditions is an interplay between collisional and radiative processes. Understanding this balance requires calculations which take both processes into account. However, the required input data are often missing, especially on the collision side. This thesis presents a study into the collisional excitation of the interstellar molecules NH, its isotopologue ND and CH$_3$OCHO, with the aim of investigating their collisionally-induced spectral features in the environments that they populate, as well as setting constraints on detecting the molecular spectra. Data files that unified both spectroscopic and collision data were compiled and run through the radiative transfer program \textsc{RADEX}. It was found that for NH and ND in diffuse molecular clouds, the produced emission lines are and will most likely remain undetectable, whereas in dark clouds they might be, provided sufficient instrument sensitivity and exposure time, as well as noise being kept to a minimum. CH$_3$OCHO was found to meet detection requirements in dark clouds. The key implication of the results are that it is now possible to directly infer abundances of the aforementioned interstellar species based on observed spectral features and knowledge about the environments that they inhabit.

Item Type:	Thesis (Bachelor's Thesis)
Supervisor name:	Tak, F.F.S. van der
Degree programme:	Astronomy
Thesis type:	Bachelor's Thesis
Language:	English
Date Deposited:	05 Jul 2023 09:44
Last Modified:	05 Jul 2023 09:44
URI:	https://fse.studenttheses.ub.rug.nl/id/eprint/30259

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