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vgauss, zvgauss: gaussian line profile with sigma in velocity

A simple gaussian line profile with the sigma parameter as velocity-width in km/s. If the width is $\leq 0$ then it is treated as a delta function. The zvgauss variant computes a redshifted gaussian.

$\displaystyle A(E) = K{1\over{(\sigma(E_l/c))*\sqrt{2*\pi}}} \exp\left({-(E-E_l)^2\over{2(\sigma(E_l/c))^2}}\right) $

where:

par1 $E_l$, line energy in keV
par2 $\sigma$, line width in km/s
Norm $K$, total photons/cm$^2$/s in the line

For zvgauss the corresponding formula is:

$\displaystyle A(E) = K{1\over{(1+z)(\sigma(E_l/c))*\sqrt{2*\pi}}} \exp\left({-(E(1+z)-E_l)^2\over{2(\sigma(E_l/c))^2}}\right) $

and parameter settings are:

par1 $E_l$, source frame line energy in keV
par2 $\sigma$, source frame line width in km/s
par3 $z$, redshift
Norm $K$, source frame total photons/cm$^2$/s in the line

The line is truncated at the point that the integrated flux under the line is within a critical value of the total flux. This critical value can be changed using xset LINECRITLEVEL. The default critical value is $1.0\times10^{-8}$.

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Next: vlorentz, zvlorentz: lorentz line Up: Additive Model Components Previous: vagauss, zvagauss: gaussian line   Contents