http://arxiv.org/abs/2112.14490
The parent paper to this Addendum describes the optimisation theory on which VPFIT, a non-linear least-squares program for modelling absorption spectra, is based. In that paper, we show that Voigt function derivatives can be calculated analytically using Taylor series expansions and look-up tables, for the specific case of one column density parameter for each absorption component. However, in many situations, modelling requires more complex parameterisation, such as summed column densities over a whole absorption complex, or common pattern relative ion abundances. This Addendum provides those analytic derivatives.
C. Lee, J. Webb and R. Carswell
Thu, 30 Dec 21
6/71
Comments: 4 pages, 2 figures. Submitted to MNRAS 23 Dec 2021, accepted 24 Dec 2021