# Sources in marx¶

marx offers several different source shapes. Tests in this module exercise those sources (except SAOSAC, which is heavily used in Point Spread Function (PSF) already).

## Build-in geometric sources¶

This test exercises build-in marx sources with different geometric shapes. Most source types have parameters, and not all parameters are tested here. See The spectrum and the spatial shape of the X-ray source for a detailed description of source parameters.

ds9 image of the simulated PSFs in alphabetical order (beta distribution, disk, disk with hole, Gauss, line, and point).

## Image as source¶

code: Image as source

An image can be used as marx input. In this case, the intensity of the X-ray radiation on that sky is taken to be proportional to the value of the image at that point.

ds9 shows the input image (left) and the simulated event list (right).

## Compiling a USER source¶

Run an example for a USER source.

marx comes with several examples for user written source in C. These can be compiled as shared objects and dynamically linked into marx at run time. To test this, we copy one of the source files from the installed marx version and compile it with gcc. This particular case is not very useful, because marx already has a point source with the same properties build-in. The purpose of this test is only to have an automatic check that the dynamic linking works.

ds9 shows that the distribution of source is indeed a point source.