ixpeobssim is a simulation and analysis framework specifically developed for the Imaging X-ray Polarimetry Explorer (IXPE). Given a source model and the response functions of the telescopes, it is designed to produce realistic simulated observations, in the form of event lists in FITS format, containing a strict superset of the information included in the publicly released IXPE data products.

The core simulation capabilities are complemented by a suite of post-processing applications which support the spatial, spectral, and temporal models needed for analysis of typical polarized X-ray sources, allowing for the implementation of complex, polarization-aware analysis pipelines, and facilitating the inter-operation with the standard visualization and analysis tools traditionally in use by the X-ray community.


ixpeobssim is made available and maintained on a best effort basis under the GNU General Public License v3, in the hope that it will be useful, but it is not officially maintained by either NASA or ASI.

The IXPE page on the HEASARC should be considered the ultimate source of information for everything concerning the observatory and the analysis of the science data it provides. Should there be any discrepancy between the information included in the ixpeobssim code and documentation and that provided by the HEASARC, the latter should be assumed to be correct. (And we kindly ask users to report any such instance on our issue tracker, so that we can fix it.)

The ixpeobssim development takes place on a git repository hosted on on github. The Installation, Overview and Quick start pages should be enough to get you up and running. If that is not the case, or should you encounter any issue at all, we encourage you to use our issue tracker to file for bug reports and feature requests.

For convenience, a static version of the latest documentation in pdf format is available at this link.

Latest changes

ixpeobssim (31.0.1) - Fri, 08 Mar 2024 08:38:15 +0100

ixpeobssim (31.0.0) - Thu, 07 Mar 2024 15:21:06 +0100

See the Release notes for a full change log.

If you found ixpeobssim useful, feel free to include an acknowledgment in papers and/or presentations—here is the most up-to-date reference.