CSim is that part of SciSim creating a simulated piece of sky, with sources with user-specified properties. It includes a Ray Generator, called GSim. Csim can produce astronomical model data for subsequent processing by the other simulators within SciSim.
X-ray sources can be created interactively or by using source lists. The results from interactive sessions can be written into output files, which can later be reused as inputs to CSim.
The following source parameters can at present be defined in CSim:
All these parameters are selected either directly from the appropriate fields in the SciSim GUI or by clicking the ``Sources'' button. The details of the parameters to choose can be found in the CSim online help.
Special parts of CSim are the S/C Simulator (SPSim) and the Ray Generator (GSim).
SPSim sets a number of important parameters for the simulation as the observation duration and telescope pointing. Some S/C effects can be modelled (jitter, drift, slew) for instrument calibration purposes but not for general XMM-Newton users.
GSim simulates the distribution of incoming photons from a given source (distribution). These rays are propagated later, by other parts of SciSim, through the telescope assemblies and into the detectors, thereby imaging the artificial view of the sky onto the detector plane.