Zhang, Jingxin;
(2025)
Development, maintenance, and post-processing tools for astrophysical spectroscopic databases.
Doctoral thesis (Ph.D), UCL (University College London).
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Abstract
Molecular spectra are critical for characterizing the atmospheres of exoplanets and cool stars, providing crucial information into their composition, temperature, and physical conditions. This thesis focuses on the development, maintenance, and post-processing tools for astrophysical spectroscopic databases, with an emphasis on enhancing the accessibility and usability of high-resolution molecular line lists. The ExoMol database provides extensive molecular line lists for high-temperature conditions relevant to exoplanetary and stellar atmospheres, which requires the maintenance and continuous updates. A newly structured file format has been implemented to improve data organization and retrieval efficiency. This work presents PyExoCross, a Python adaptation of the Fortran-based ExoCross program, designed for post-processing huge molecular line lists. PyExoCross facilitates the computation of local thermodynamic equilibrium (LTE) and non-local thermodynamic equilibrium (non-LTE) stick spectra, cross sections, partition functions, specific heats, cooling functions, lifetimes, and oscillator strengths, supporting ExoMol , HITRAN, and HITEMP databases. The ExoMolHR tools is introduced as an empirical high-resolution molecular spectrum calculator, enabling users to generate spectra for specific temperature and wavenumber/wavelength ranges. This web-based database allows users to download and visualize spectral data efficiently, bridging the gap between raw molecular line lists and practical astrophysical applications. The advancements presented in this thesis significantly improve the computational tools available for analyzing molecular spectra in astrophysics, supporting ongoing and future exoplanetary and stellar atmosphere studies.
| Type: | Thesis (Doctoral) |
|---|---|
| Qualification: | Ph.D |
| Title: | Development, maintenance, and post-processing tools for astrophysical spectroscopic databases |
| Open access status: | An open access version is available from UCL Discovery |
| Language: | English |
| Additional information: | Copyright © The Author 2025. Original content in this thesis is licensed under the terms of the Creative Commons Attribution 4.0 International (CC BY 4.0) Licence (https://creativecommons.org/licenses/by/4.0/deed.en). Any third-party copyright material present remains the property of its respective owner(s) and is licensed under its existing terms. Access may initially be restricted at the author’s request. |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Physics and Astronomy |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10207710 |
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