An X-Ray Spectral Fitting Package

User's Guide for version 12.3.1

• Updates to the Manual
• Introduction to the new version, 12.0
• Spectral Fitting and XSPEC
• XSPEC Overview and Helpful Hints
• Walks through XSPEC
• XSPEC Commands
• XSPEC V12 Models
• Appendices

Keith Arnaud, Ben Dorman, and Craig Gordon

HEASARC

Astrophysics Science Division

NASA/GSFC

Greenbelt, MD 20771

Mar 2007