File: model read from a fileΒΆ
This model reads a spectrum from a file. The user inputs a spectrum at \(n\) energy bins (\(n>1\)). The file containing the spectrum should have the follwing format:
first line: \(n\)
second line: \(E_1\), \(S_1\)
third line: \(E_2\), \(S_2\)
\(\ldots\)
last line: \(E_n\), \(S_n\)
Here \(E_i\) is the energy of a photon in keV, and \(S_i\) is the spectrum in units of \(10^{44}\) photons \(\mathrm{s}^{-1}\) \(\mathrm{keV}^{-1}\). All energies \(E_i\) must be positive, and the grid must be monotonically increasing (two subsequent energies may not have the same value). Also, the spectrum \(S_i\) must be strictly positive (i.e. \(S_i=0\) is not allowed).
SPEX then calculates the spectrum by linear interpolation in the \(\log E - \log S\) plane (this is why fluxes must be positive). For \(E<E_1\) and \(E>E_n\) however, the spectrum is put to zero. Finally, the spectrum is multiplied by the scale factor \(N\) prescribed by the user.
The parameters of the model are:
norm : Normalisation factor \(N\). Default value: 1.file : The file name of the file containing the spectrum