# CHIANTI - an atomic database for emission lines - Paper XV: Version 9, improvements for the X-ray satellite lines

## TL;DR

CHIANTI Version 9 enhances X-ray satellite line modeling by explicitly including autoionization and dielectronic recombination, updating datasets, and adding new ions, thereby improving astrophysical spectral analysis tools.

## Contribution

The paper introduces improvements in CHIANTI Version 9, notably the explicit modeling of satellite lines with autoionization and dielectronic recombination processes, and updates to atomic data.

## Key findings

- Improved modeling of X-ray satellite lines.
- Updated atomic datasets and added new ions.
- Enhanced accuracy of astrophysical spectral analysis.

## Abstract

CHIANTI contains a large quantity of atomic data for the analysis of astrophysical spectra. Programs are available in IDL and Python to perform calculation of the expected emergent spectrum from these sources. The database includes atomic energy levels, wavelengths, radiative transition probabilities, rate coefficients for collisional excitation, ionization, and recombination, as well as data to calculate free-free, free-bound, and two-photon continuum emission. In Version 9, we improve the modelling of the satellite lines at X-ray wavelengths by explicitly including autoionization and dielectronic recombination processes in the calculation of level populations for select members of the lithium isoelectronic sequence and Fe XVIII-XXIII. In addition, existing datasets are updated, new ions added and new total recombination rates for several Fe ions are included. All data and IDL programs are freely available at http://www.chiantidatabase.org or through SolarSoft and the Python code ChiantiPy is also freely available at https://github.com/chianti-atomic/ChiantiPy.