[RM-9442] [multiobs] multiplicative intercalibration

Created on 2025-01-22 13:59:15 by Didier Vibert. % Done: 0

fit an amplitude per observation in the continuum fitting for templateFitting/powerLaw methods

for the lineModel, 2 cases:

• when no continumm has been fitted (because of negative/bad chi2/compatible with null or fromspectrum initial setting): fit one amplitude per observation for the line ratios case. For the linemodel free, each line is fitted independently thus there is nothing to add, even for lines belonging to several observations. The only specific case to handle is when a fixed doublet has one line in 2 observations and the other line is observed only once...
• when a continuum has been fitted, with a multiplicative intercalibration, the amplitude ratio between observations determined with the continuum should be propagated to the linemodel Fit.

For the fit of the intercalibration one can leave the input variance as is or put this free parameter also in the input variance