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Paper: New Spectral Analysis Software for Global Analysis of Broadband Line Surveys in MATLAB
Volume: 475, Astronomical Data Analysis Software and Systems XXII
Page: 283
Authors: Radhuber, M. L.; Widicus Weaver, S. L.
Abstract: New observatories with broadband spectral capabilities such as the Herschel Space Observatory, the Stratospheric Observatory for Infrared Astronomy, and the Atacama Large Millimeter Array necessitate the development of more robust and efficient spectral assignment methods. These observatories provide the opportunity to tightly constrain physical conditions in astronomical sources through the large number of transitions observed for a given molecule in a single dataset. However, these datasets also present a daunting analysis challenge due to the vast amount of data and the presence of blended line features which cannot be met by traditional line identification and rotation diagram analysis. To meet this new challenge, we have written a program in the MATLAB numerical computing environment. This new program has been designed to achieve simultaneous multi-molecule, multi-component fitting for an entire broadband spectrum. This program improves on existing analysis methods in that it does an iterative fit to an observational spectrum using a global analysis method. This global analysis includes global fitting for multiple molecules and single molecules with multiple density, temperature, and velocity components. The advantage of this global method over traditional line-by-line analysis is that it is less sensitive to blended features which are so prevalent in many of these datasets. The current version of the program is limited to the local thermodynamic equilibrium (LTE) approximation because radiative transfer information is not available for all of the complex molecules that are now routinely observed. However, an advantage of this LTE approximation is that its simplicity allows for rapid analysis of a line survey.
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