Determine the equivalent width of a model component.
XSPEC> eqwidth [[RANGE <frac range>] <model component number>]...
The command calculates the integrated photon flux produced by an additive model
component (FLUX), the location of the peak of the photon spectrum (E), and the
flux (photons per keV) at that energy of the continuum (CONTIN). The equivalent
width is then defined as EW = FLUX / CONTIN in units of keV. The
continuum currently is defined to be those other
components of the selected model's additive group (see the model command).
Thus, neither components in other additive groups nor the effect of any
multiplicative components (e.g., absorption) are used in the calculation of
the continuum or the equivalent width.
There are certain models with a lot of structure where, were they
the continuum, it might be inappropriate to estimate the continuum flux at
a single energy. The RANGE keyword allows the setting of a fractional size
to be used over which the continuum model is integrated (from E
(1-<fracr>) to
E(1+<fracr>). The initial value for <fracr> is 0.05.