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K. A. Misselt, G. C. Clayton (LSU)
We have developed a Monte Carlo radiative transfer model which explicitly includes geometry, dust distribution and grain scattering properties in a mixture of stars, gas, and dust to predict observed spectra self-consistently from the ultraviolet to the far-infrared. The treatment of the heating and re-emission from dust in the model includes multiple dust grain components and a full treatment of transient heating effects. The model uses Monte Carlo techniques to realistically model the transfer of UV and optical photons through dust with a range of optical depths and geometries, both local and global. Within each model grid point, the energy absorbed by each grain component is computed given a specific grain model. From the absorbed energy and the principle of energy balance, the dust emission spectrum can be calculated. Thus the model is self-consistent in the sense that the dust heating and hence emission is produced by the input radiation source. The calculated emission from the dust can then be fed back into the Monte Carlo radiative transfer and a new absorbed energy grid is calculated, from which a new dust temperature and emission spectrum are calculated. This procedure is iterated until the calculated dust temperature in each bin converges. Currently, we employ a three component dust grain model including graphite, silicates, and PAH molecules. The grain model is easily extensible to include more or fewer components depending on the astrophysical system being modeled. The application of the model to starburst galaxies is discussed and model UV--IR SEDs of starburst galaxies are presented and compared to observations.
The author(s) of this abstract have provided an email address for comments about the abstract: misselt@rouge.phys.lsu.edu