Preparing SPEX for the next generation of high-resolution spectrometers

SPEX is a spectral fitting package optimised for high-resolution spectroscopy. It has been developed since the 1990’s and was based on the popular MEKAL code. In the last decade, we expanded the atomic database, added new models and improved the user experience. A new 3D model for clusters of galaxies and a time-dependent non-equilibrium photo-ionisation model are two of the most recent additions. Like most of the SPEX models, the software provides several output options for plasma parameters like, for example, ionisation balance, transition rates, and line lists, which enables advanced interpretation of the plasma properties. A Python interface is added, allowing users to control and get data from a SPEX session, which makes scripting much easier. This year, we expect to release SPEX version 4. This version will have a modular setup with documented libraries, enabling the integration of SPEX in other software. With the upcoming launch of XRISM, we will have a very capable spectral fitting tool to interpret the upcoming high-quality spectra from Resolve, but also the existing high-resolution grating spectra of XMM-Newton and Chandra.