SPECFIT is a tool for fitting complex models of emission lines, absorption lines, and continua to 1-dimensional spectra. SPECFIT was developed by Gerard Kriss of the Department of Physics and Astronomy at the Johns Hopkins University originally for fitting data obtained by the Hopkins Ultraviolet Telescope (HUT). It runs in the IRAF environment, either interactively, or as a background task.
SPECFIT is distributed within the "contrib" package of STSDAS. However, if you have not installed STSDAS on your system and would like to obtain SPECFIT, you can download this version as a tar file:
See the README files in these distributions for installation instructions.
For an overview of SPECFIT and examples of what it can do, see Fitting Models to UV and Optical Spectral Data: Using SPECFIT in IRAF , by G. A. Kriss (1994), in Astronomical Data Analysis Software & Systems III, A.S.P. Conf. Series, Vol. 61, ed. D. R. Crabtree, R. J. Hanisch, & J. Barnes (Astronomical Society of the Pacific: San Francisco), p. 437. Please cite this reference if SPECFIT contributes substantially to any published work.
For more detailed help on the actual use of SPECFIT, see the IRAF help page.
SPECFIT has a steep learning curve. If you run into trouble, it is often helpful for the user to send a copy of their parameter file (obtained by performing "lpar specfit"), a copy of their database file, and a copy of the spectral data being fit.