Skip to main content

Come analyze HEASARC, IRSA, and MAST data in the cloud! The Fornax Initiative is now welcoming all interested beta users.

Xspec Home Page

next up previous contents
Next: comptb: Thermal and bulk Up: Additive Model Components Previous: compPS: Comptonization, Poutanen &   Contents


compST: Comptonization, Sunyaev & Titarchuk

A Comptonization spectrum after Sunyaev & Titarchuk (1980, A&A 86, 121). This model is the Comptonization of cool photons on hot electrons.

par1 temperature in keV
par2 optical depth
norm $Nf/4\pi d^2$, where $N$ is the total number of photons from the source, $d$ is the distance to the source, f is the factor $f=z(z+3)y^z/\Gamma(2z+4)/\Gamma(z)$, $z$ is the spectral index, $y$ is the injected photon energy in units of the temperature, and $\Gamma$ is the incomplete gamma function.