XISSIM: XIS Event Simulator

Xissim simulates XIS photon events. It is useful for simulating contamination from nearby sources or diffuse sources, which is difficult to evaluate from a simple simulation with XSPEC. To generate a simulated event list, users should take three main steps:

1) decide how to place the XIS field of view (FOV) on the sky;
2) fake incident photons from celestial sources in the XIS FOV with mkphlist; and
3) simulate XIS events of the faked photons with xissim, which takes into account the XRT efficiency and the XIS response.

The final event list has the event FITS format, so that users can analyze the simulated data as the actual data analysis.

Xissim (version 2006-08-02) and related tools are available as components of the Suzaku FTOOLS. Calibration files needed to run xissim are mostly available in the Suzaku CALDB package.

Important Note: we strongly recommend downloading the following files:

These are the new versions of the calibration files for the OBF contaminant. The versions currently available in the CALDB will lead to overestimation of contamination.

We also recommend using the XIS response files for simulations in running xissim. This, however, is less critical than using the new contamination calibration files.

In addition, Cycle 2 observations will be carried out using spaced-row charge injection (CI). CI leads to dead areas of 5.6% for the FI CCDs and 7.4% for the BI CCD. This is not taken into account in simulations using xissim. In most cases, it should be sufficient to adjust the exposure time outside the simulation, however.

The following pages describe a step-by-step guide of the simulation procedure.

  1. Mapping the XIS FOV on the sky
  2. Faking incident photons with mkphlist
  3. Simulating XIS events with xissim