A number of tools are available to use by scientists wishing to simulate ATHENA results.

Response matrices

See: ixo_wfi_default_owl_0.15_11.5_09052011.rsp and ixo_xms_none_owl_0.15_11.5_09052011.rsp

Background

Non-X-ray Background
For the background it is recommended to use the numbers derived for IXO corresponding to a relatively flat particle background over the spectral range that has been verified by various detailed GEANT4 simulations and extrapolations from in-orbit telescopes:

2 × 10-² counts/cm²/keV/s for XMS (detector area)
5 × 10-² counts/cm²/keV/s for WFI (detector area)

Diffuse X-ray Background
In addition to the unrejected particle background, simulations also consider any unresolved diffuse X-ray background. While this is a judgment for the individual case, one can consider a typical high latitude background modelled as:

Galactic + Extragalactic: (S*phabs*[F*pow+MEKAL+MEKAL])

with the following parameters:

Here S is a scaling factor = 7.4 × 10^-9 (for a detection cell of 2 × Half Energy Width of 10 arcsec), and where for the power law component (pow) an additional reduction factor, F, may be required for (say) 90 per cent of sources being resolved.

Questions about these resources may be directed to:
David Lumb, ESA Study Scientist
Email: David.Lumbesa.int

IXO Simulator

The simx code simulates the IXO FMA response to an input point source or FITS image (from Chandra, XMM-Newton, or other source) and model X-ray spectrum.