VoigtFit: A Python package for Voigt profile fitting

TL;DR

VoigtFit is a versatile Python package that simplifies fitting Voigt profiles to absorption lines, supporting multiple components, continuum modeling, physical constraints, and interactive features for improved user control.

Contribution

It introduces a comprehensive Python tool for Voigt profile fitting that integrates multiple features like physical modeling and interactivity, enhancing flexibility and usability.

Findings

Supports simultaneous multi-component fitting

Includes automatic continuum and physical model fitting

Offers interactive tools for initial guess estimation

Abstract

I present a Python package developed for fitting Voigt profiles to absorption lines. The software fits multiple components for various atomic lines simultaneously allowing parameters to be tied and fixed. Moreover, the code is able to automatically fit a polynomial continuum model together with the line profiles. Lastly, a physical model can readily be used to constrain thermal and turbulent broadening of absorption lines as well as implementing molecular excitation models. The code can be run with interactive features such as manual continuum placement locally around each line, manual masking of undesired fitting regions, and interactive definition of velocity components for various elements. This greatly improves the ease by which the initial guesses can be estimated. Since the code is written in pure Python, it can easily be scripted and modified to fit the user's needs. The code uses a $\chi^2$ minimization approach to find the best solution. The code and a set of test-data together with the full documentation is available on GitHub.