SOXS: Simulated Observations of X-ray Sources

Simulated X-ray events from a spiral galaxy from the Illustris simulation, assuming Chandra/ACIS-I on the left and Lynx/HDXI on the right. Both exposures are 50 ks.

SOXS is a software suite which creates simulated X-ray observations of astrophysical sources. The goal of SOXS is to provide a comprehensive set of tools to design source models and convolve them with simulated models of X-ray observatories. In particular, SOXS is the primary simulation tool for simulations of Lynx observations.

There are two main entry points to SOXS: a Python interface, and a command-line interface. The former has more power and flexibility, but the latter is often simpler to use. Both of these entry points are extensively documented here with examples. Though you will find details on usage and example runs of the command line scripts in the SOXS Command Line Interface Guide, it is recommended to also look over the corresponding documentation in the SOXS Users’ Guide for details about what is going on under the hood.

Why Another Mock X-ray Observation Package?

There are already a number of successful efforts to create mock X-ray observations, and it is a sensible question as to why it would not have made more sense to adapt one of the existing projects for Lynx simulations. There are three basic reasons why we have chosen to develop a new package:

First, SOXS is explicitly geared towards simulating observations of X-ray sources with Lynx (formerly “X-ray Surveyor”). This tool is designed to provide support for developing a science case for the Lynx mission concept and help drive the design of the instruments. Having a standalone package (that still plays nice with others) that serves as a “one-stop shop” for Lynx simulations simplfies this task.

Second, SOXS is being developed in Python, reflecting the growing popularity of the use of Python in astronomy and astrophysics. Though there are a number of command-line scripts provided in SOXS, which can carry out the most important tasks, the Python interface to SOXS is more powerful and flexible. Working with the Python interface also provides a direct connection to other Python packages for science in general and astronomy in particular, including NumPy, SciPy, AstroPy, yt, and pyXSIM.

Thirdly, SOXS is being developed out in the open, on GitHub, to encourage contributions in the form of bugfixes and enhancements, and to make contributing as simple as forking the code and submitting a pull request for review.


SOXS is released under a BSD 3-clause license.

Current Version

The current stable version is 2.1.0. See the ChangeLog for details on changes from previous versions.


  • John ZuHone (CfA)
  • Scott Randall (CfA)
  • Felipe Andrade-Santos (CfA)
  • Herve Bourdin (CfA)
  • Alexey Vikhlinin (CfA)
  • Reinout Van Weeren (CfA)
  • Akos Bogdan (CfA)

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