# The Nested_fit data analysis program

## TL;DR

Nested_fit is a Bayesian data analysis tool utilizing nested sampling, designed for atomic spectra and physical data, offering model comparison and parameter estimation with a versatile spectral profile database.

## Contribution

It introduces Nested_fit, a novel Bayesian analysis program with an upgraded sampling method and a flexible spectral profile database for physical data investigations.

## Key findings

- Provides Bayesian evidence for model comparison
- Offers detailed parameter probability distributions
- Includes a large, expandable spectral profile database

## Abstract

We present here Nested_fit, a Bayesian data analysis code developed for investigations of atomic spectra and other physical data. It is based on the nested sampling algorithm with the implementation of an upgraded lawn mower robot method for finding new live points. For a given data set and a chosen model, the program provides the Bayesian evidence, for the comparison of different hypotheses/models, and the different parameter probability distributions. A large database of spectral profiles is already available (Gaussian, Lorentz, Voigt, Log-normal, etc.) and additional ones can easily added. It is written in Fortran, for an optimized parallel computation, and it is accompanied by a Python library for the results visualization.