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G.J. Ferland (University of Kentucky)
Cloudy is a large-scale spectral-simulation code that is designed to reproduce the full range of conditions that can be encountered in emission- or absorption-line regions. The gas density can lie between the low-density Intergalactic Medium and high-density LTE limits, and gas temperature between 2.7 K and 10 billion K. The ionization / chemistry limits extend from fully stripped nuclei to the molecular limit, where molecular hydrogen and carbon monoxide are fully formed. The code is openly available on the internet at www.nublado.org
The fidelity of the simulation has always been limited by processor power. We are currently extending the code in several directions to take advantage of more powerful machines. Radiative transfer is now done with escape probabilities, and is being extended to accelerated lambda iteration. The geometry is now 1D, but the new radiative transfer methods will allow higher dimensionality. Dynamical flows, such as those found on the boundary of an irradiated molecular cloud, can be simulated. This will eventually extend to shocks.
All of these simulations rest on a foundation of atomic and molecular data. I will outline some of the most pressing data needs. The SELAC consortium ( www.orau.org/selac ) has been formed as a clearinghouse for the generation of such data.
If you would like more information about this abstract, please follow the link to www.nublado.org. This link was provided by the author. When you follow it, you will leave the Web site for this meeting; to return, you should use the Back comand on your browser.
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Bulletin of the American Astronomical Society, 37 #2
© 2005. The American Astronomical Soceity.