pahfitMCMC

I've developed a Python version of J.D. Smith's PAHFIT code, pahfitMCMC.py. The goal of either code is to decompose IRS SL/LL spectra and calculate properties of emission lines and PAH features. mcmcPAHFIT also calculates silicate indices based on the line-subtracted spectrum; see Spoon et al. (2007) for an explanation of silicate index.

From the name you can guess that it uses Markov Chain Monte Carlo as the optimizer. The advantage is that uncertainties are properly generated from samples of the posterior probability distribution. Perhaps a more significant advantage is that no IDL license is required, and Python is free as in beer.

You may download a tar-ball here: pahfitMCMC.tgz. Documentation is contained within.

Here's an example decomposition of PG0050+124 (Link goes to the CASSIS website). Notice that pahfitMCMC fits the 14 micron "jump" that results from the change in slit-width between SL and LL.

As far as I'm concerned, you are free to use it in exchange for a thoughtful and kind acknowledgement to yours truly. The (simple) silicate emission model that is used in pahfitMCMC is discussed in Gallimore et al. (2010).