Yaxx1 is a Perl script that facilitates batch data processing using Perl open source software and commonly available software such as CIAO/Sherpa, S-lang, SAS, and FTOOLS. For Chandra and XMM analysis it includes automated spectral extraction, fitting, and report generation. The primary emphasis is on having a simple tool that can be run without requiring an extensive learning curve. However, for those with the motivation, yaxx is highly configurable and can be customized to support complex analysis. In particular yaxx uses template files and takes full advantage of the unique Sherpa / S-lang environment to make much of the processing user configurable.

Although originally developed with an emphasis on X-ray data analysis, yaxx has evolved to be a general-purpose pipeline scripting package. The current development version of yaxx has been substantially refactored to separate the core pipeline functionality from the specific analysis threads. Scientists doing repetitive and scriptable data processing will find benefit from the functionality provided by yaxx.

NEWS (2013-Apr-06): Yaxx is NO LONGER SUPPORTED and will not work with recent versions of CIAO. This page is maintained only for archival reasons.

Presently Yaxx supports Linux, Mac OSX, and Solaris 2.8 platforms.

Yaxx has been developed by Tom Aldcroft with support from NASA under NASA grant NAS8-39073 and CXC archival research grant AR2-3009X (ChaMP collaboration).

If you want to receive information about updates, or if you have questions, please send email to

Copyright (C) 2006 by the Smithsonian Astrophysical Observatory.

1Yaxx is not an acronym and should never be written as YAXX.