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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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powerlaw, zpowerlw: power law photon spectrum

powerlaw is a simple photon power law. The zpowerlw variant computes a redshifted spectrum.

$\displaystyle A(E) = K E^{-\alpha} $

where:

par1 $\alpha$, photon index of power law (dimensionless)
norm $K$, photons/keV/cm$^2$/s at 1 keV

For zpowerlw the formula and corresponding parameters are:

$\displaystyle A(E) = K [E(1+z)]^{-\alpha} $

where:

par1 $\alpha$, photon index of power law (dimensionless)
par2 $z$, redshift
norm $K$, photons/keV/cm$^2$/s at 1 keV

If POW_EMIN and POW_EMAX have been defined by the xset command then the norm becomes the flux in units of $10^{-12}$ ergs/cm$^2$/s over the energy range (POW_EMIN, POW_EMAX) keV unless POW_EMIN = POW_EMAX in which case the norm becomes the flux density in micro-Jansky at POW_EMIN keV. In these cases it is important that POW_EMIN and POW_EMAX lie within the energy range on which the model is being evaluated.

next up previous contents
Next: pshock, vpshock, vvpshock, bpshock, Up: Additive Model Components Previous: posm: positronium continuum   Contents