Slitless Spectroscopy: Inverse Solutions With Overlapping Lines

Friday, 19 December 2014
Joseph M Davila, NASA Goddard SFC, Greenbelt, MD, United States and John Francis O'Neill Jr, Catholic University of America, Washington, DC, United States
Spectrometers provide our most detailed diagnostics of the solar coronal plasma, and spectral data is routinely used to measure the temperature, density, and flow velocity in coronal features. However spectrographs suffer from a limited instantaneous field-of-view (IFOV), and imaging instruments, on the other hand, can provide a relatively large IFOV but offer only very limited spectral resolution. In previous work, synthetic data was produced which had spectral properties derived from the observations of the Hinode/EIS spectrometer. We assumed observations in multiple spectral orders, then used an inverse problem method to infer the spectral properties of the solar source. Physical constraints and regularization derived from prior knowledge were incorporated as part of the solution process.

However in previous work a single emission line without overlapping from neighboring lines was assumed. In this paper we present solutions of a more realistic case solving for spectral line intensity, Doppler shift, and Gaussian width in the case where overlapping lines are present.