vagauss, zvagauss: gaussian line profile in wavelength space with sigma in velocity

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

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

where:

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

For zvagauss the corresponding formula is:

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

and the parameters are:

par1 = $\lambda_l$	line wavelength in Angstrom
par2 = $\sigma$	line width in km/s
par3 = z	redshift
Norm = K	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 $1.0\times10^{-6}$.

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Last modified: Friday, 23-Aug-2024 13:20:40 EDT