gauss, zgauss: gaussian line profile

A simple gaussian line profile. If the width is $\leq 0$ then it is treated as a delta function. The zgauss variant computes a redshifted gaussian.


\begin{displaymath}
A(E) = K{1\over{\sigma*\sqrt{2*\pi}}} \exp\left({-(E-E_l)^2\over{2\sigma^2}}\right)
\end{displaymath}

where:

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

For zgauss the corresponding formula is:


\begin{displaymath}
A(E) = K{1\over{(1+z)\sigma*\sqrt{2*\pi}}} \exp\left({-(E(1+z)-E_l)^2\over{2\sigma^2}}\right)
\end{displaymath}

and parameter settings are:

par1 $E_l$, source frame line energy in keV
par2 $\sigma$, source frame line width in keV
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 $1.0\times10^{-8}$.