Current and future development of the photoionization code Cloudy

Abstract

The gas that is present in the interstellar medium is usually very far removed from (local) thermodynamic equilibrium, and in some cases may also not be in a steady-state equilibrium with its surroundings. The physics of this material is complex and one needs a sophisticated numerical code to study it. For this purpose the open-source photoionization code Cloudy was created. It models the physical state of the gas and predicts the spectrum that it emits. Cloudy is continually being developed to improve the treatment of the microphysical processes and the database of fundamental data that it uses. In this paper we will discuss how we are developing the code to improve our high-density predictions by implementing better collisional-radiative models for all ions. We will also briefly discuss the experimental mode in Cloudy to model gas that is not in steady-state equilibrium and present a preliminary model of recombining gas in a planetary nebula that is on the cooling track. We finish with a short discussion of how we are speeding up the code by using parallelization.

12 pages, 5 figures. This paper was presented as an invited lecture at the 12th Serbian Conference on Spectral Line Shapes in Astrophysics in Vrdnik, Serbia

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• J-resolved He I emission predictions in the low-density limit
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Cited by in corpus (2)

• Radiative transfer of ionizing radiation through gas and dust: grain charging in star forming regions
• Recombination of hot ionized nebulae: The old planetary nebula around V4334 Sgr (Sakurai's star)