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		| Paper: | Fitting Models to UV and Optical Spectral Data |  
		| Volume: | 61, Astronomical Data Analysis Software and Systems III |  
		| Page: | 437 |  
		| Authors: | Kriss, G. |  
		| Abstract: | Fast work stations make the fitting of complex, multi-parameter models to UV and optical spectral data practical for the average user. I will describe an interactive tool called specfit that runs in the IRAF environment which can fit data spanning a large in wavelength from a variety of instruments using a -minimization technique. Data can be input either as IRAF images or as ASCII files containing triplet entries of wavelength, flux, and errors. A variety of functional forms can be used to describe the continuum, emission lines and absorption lines, including user-defined functions that are input as ASCII files. The user has a choice of either a simplex algorithm or a Levenburg-Marquadt procedure for minimizing . specfit can run either interactively, in which case the user can modify parameters and display various representations of the data and the current fit, or as a background task. |  
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