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agauss, zagauss: gaussian line profile in wavelength space

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

$\displaystyle A(\lambda) = K {1\over{\sigma\sqrt{2\pi}}} \exp(-(\lambda-\lambda_l)^2/2\sigma^2) $

where:

par1 = $\lambda_l$ line wavelength in Angstrom
par2 = $\sigma$ line width in Angstrom
Norm = K total photons/cm$^2$/s in the line

For zagauss the corresponding formula is:

$\displaystyle A(\lambda) = K {(1+z)\over{\sigma\sqrt{2\pi}}} \exp(-(\lambda/(1+z)-\lambda_l)^2/2\sigma^2) $

and the parameters are:

par1 = $\lambda_l$ line wavelength in Angstrom
par2 = $\sigma$ line width in Angstrom
par3 = z redshift
Norm = K total photons/cm$^2$/s in the line

The line is calculated out to six sigma.