SEDfit: Software for Spectral Energy Distribution Fitting of Photometric Data

Abstract

This article describes SEDfit, the earliest—but continually upgraded—software package for spectral energy distribution fitting (SED fitting) of high-redshift photometric data, and the only one to properly treat nondetections. The principles of maximum-likelihood SED fitting are described, including formulae used for fitting both detected and undetected (upper limits) photometric data. The internal mechanics of the SEDfit package are presented and several illustrative examples of its use are given. The article concludes with a discussion of several issues and caveats applicable to SED fitting in general.