HEASOFT

HEASoft is a software package for the analysis of high-energy astrophysics data, developed and maintained by the High Energy Astrophysics Science Archive Research Center (HEASARC) at NASA. It provides a unified distribution of tools and applications used to reduce, analyze, and interpret data from X-ray and gamma-ray missions. The package bundles the general-purpose FTOOLS alongside mission-specific and science-oriented programs such as XSPEC for spectral fitting, XRONOS for timing analysis, XIMAGE for imaging, and XSELECT for data selection, among others. HEASoft is designed to work with FITS data formats common in the field and to support data from a wide range of missions, including RXTE, Chandra, XMM-Newton, Swift, INTEGRAL, NuSTAR, and Fermi.

The project originated from the HEADAS initiative in the 1990s and has evolved into HEASoft as a broader, cross-mission software suite. It emphasizes cross-platform compatibility, with supported builds for Windows, macOS, and Linux, and is distributed with both precompiled binaries and source code. The software relies on external libraries such as CFITSIO for FITS I/O, and it is documented with user guides, tutorials, and API references.

HEASoft remains a central tool in the high-energy astrophysics community for tasks including data screening and calibration, event selection, spectral analysis, timing studies, and image processing. It is distributed free of charge through the HEASARC website, with ongoing updates to accommodate new missions, calibration products, and data formats.