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To find and download HEASARC data in the cloud, you can use astroquery.heasarc or download our new tool, hark.

The HEASARC and NuSTAR teams are greatly saddened by the sudden passing of Katja Pottschmidt. Most recently Katja was the lead scientist for the NuSTAR Guest Observer Facility (GOF), a role she had supported for many years. During her science career she worked on many other high energy astrophysics missions and played an integral role in advancing our knowledge of the universe. She was a wonderful colleague and friend and will be keenly missed by all who knew her.

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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.

$\displaystyle 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:

$\displaystyle 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 $1.0\times10^{-6}$.

next up previous contents
Next: vgauss, zvgauss: gaussian line Up: Additive Model Components Previous: wdem, vwdem, vvwdem, bwdem,   Contents