Stierhof: copy from old wiki

2018-04-11T12:09:35Z

copy from old wiki

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Define the equivalent width (eqw) fit-function with the number of components you need to calculate the eqw of:
eqwFit_init(1);
Set the model with the underlying continuum given as first parameter to the eqwFit fit-function and the components as further parameters, e.g.:
<pre>
fit_fun("eqwFit(1, powerlaw, egauss)*tbnew_simple");
</pre>
This will renormalize the egauss to match the corresponding eqw-parameter (see below) based on an ''unabsorbed'' power-law continuum, which is absorbed afterwards. Then, you should set appropriate parameter ranges for the eqw-parameter, e.g. allow only negative values in case of an absorption feature:
<pre>
set_par("eqwFit(1).width1"; min = -1000, max = 0);
</pre>

If you want to calculate the eqw of two components, you first need to initialize the eqw fit-function in a new (!) Isis-shell:
<pre>
eqwFit_init(2);
fit_fun("eqwFit(1, powerla, egauss(1), egauss(2))*tbnew_simple");
</pre>

[[Category:Isis / Slang]]

Fitting Equivalent Widths - Revision history

Stierhof: copy from old wiki