What’s New with Xstar

Xstar is a computer package designed for simulating spectra from plasmas in various contexts. These include Active Galactic Nuclei (AGN) accretion flows and outflows, circumstellar gas in accreting binary stars, and interstellar matter. We have continued to improve and develop Xstar since its inception more than 20 years ago. Current modifications include a set of Python Fortran wrappers that will make it easier for users to access the internal quantities that the code uses to calculate the spectrum. In addition, we are developing Python tools for accessing and curating (maintenance and upgrades) the atomic database. These will allow the user to access both the ‘raw’ atomic data, (e.g., transition probabilities, cross sections, and collision strengths) and also the rate coefficients as functions of the plasma conditions. We are creating a library of Python wrappers (PyXstar) for the various Xstar modules, along with a framework for calling them sequentially to provide model spectra but allowing the user at the same time to intercept internal quantities that provide validation and physical insight to the final fit. Other improvements include porting the code to a more nearly native Python environment, facilitating execution on parallel machines, updates to the atomic database, exploration of time dependence, and upgrades to the documentation.