Skip to main content

HEASoft and XSPEC are now available as conda packages. See details ....

Image cover
An X-Ray Spectral Fitting Package


Users' Guide for version 12.15.0


Keith Arnaud, Craig Gordon, Ben Dorman & Kristin Rutkowski

HEASARC
Astrophysics Science Division
NASA/GSFC
Greenbelt, MD 20771

March 2025