[RM-6459] template ratio ism extinction should not be applied to amplitude of absorption lines...

Created on 2021-04-16 16:37:15 by Didier Vibert. % Done: 100

amplitude of absorption lines are unitless coefficient in [0,1] and the effective spectral profile is

s(lamda) = C(lambda)*(1-a)*LineProfile(lambda) where C(lambda) is the continuum, a is the fitted absorption amplitude and LineProfile is a normalized profile with maximum at 1.

Thus the extinction of the continuum is operating on the absorptions lines, and it should not be applied a second time on the amplitude a. The current code for template ratio currently multiply the amplitude by the extinction low. It should not.