Emission Line Spectrum Analyzer

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What is ELSA?

ELSA is an astrophysics software package for analyzing the spectral data from emission line objects and deriving chemical abundances in those objects. It is written in C and compatible with a wide range of Unix systems. ELSA has numerous features, including easy data acquisitions from logs produced by the IRAF splot task, an exceptionally sophisticated interstellar dereddening correction scheme, a robust implementation of the standard 5-level-atom approximation based on Dick Henry's abun code (Kwitter & Henry, 2001, ApJ, 562, 804) and the ability to produce output tables in LATEX format for use in preprints and papers.

ELSA is available for free to researchers in source code form. It includes extensive documentation as well. The latest version can be found on this website. ELSA is in continual development. We greatly appreciate any feedback from users.

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About the authors

ELSA was conceptualized and developed in the summer of 2005 at Williams College by Matthew D. Johnson (Wesleyan '07) and Jesse S. Levitt (Williams '08). It originated as a means of doing batch processing of measured spectral data, and subsequently expanded to include the abundance calculation and other useful processes.


The authors gratefully acknowledge professors Karen Kwitter of Williams College and Dick Henry of the University of Oklahoma, whose research was the genesis of this project. We are also grateful to the Keck Northeast Astronomy Consortium, which is partially supported by the National Science Foundation, and to the Bronfman Science Center and Astronomy Department of Williams College. This research has been partially conducted under the auspices of NSF grant AST 03-07118 to the University of Oklahoma.

Site updated 9/2/2010