The 2025 Release of Cloudy
Chamani M. Gunasekera, Peter A. M. van Hoof, Maryam Dehghanian, Priyanka Chakraborty, Gargi Shaw, Stefano Bianchi, Marios Chatzikos, Masahiro Tsujimoto, and Gary J. Ferland

TL;DR
The 2025 Cloudy release introduces enhanced physics, improved spectral resolution, updated databases, and expanded molecular networks, significantly advancing spectral synthesis capabilities for astrophysical and exoplanetary research.
Contribution
This release provides major updates to Cloudy, including resolving Lyman alpha lines, updating ionization data, expanding molecular networks, and preparing for future observatory data analysis.
Findings
Improved spectral resolution for X-ray applications.
Enhanced molecular and chemical modeling capabilities.
Updated databases for more accurate simulations.
Abstract
We present the 2025 release of the spectral synthesis code Cloudy, highlighting significant enhancements to the scope and accuracy of the physics which have been made since the previous release. A major part of this development involves resolving the Lyman line into -resolved fine-structure doublets, making Cloudy of use to the X-ray community. On this front, we have also updated inner-shell ionization line energies and incorporated the 1 keV feature commonly observed in X-ray binaries. Additionally, we update our in-house database, Stout, for the carbon isoelectronic sequence, improving Cloudy microphysical calculations for all wavelengths. We have also extended the molecular network by adding new silicon-bearing species, titanium-related reactions, and phosphorus-containing molecules, enhancing Cloudy's ability to model the complex chemistry relevant to rapidly growing…
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Taxonomy
TopicsAstronomy and Astrophysical Research · SAS software applications and methods · Gamma-ray bursts and supernovae
