↩ 🔵 🔵 🔵 ❪𖣐❫ High-Energy Astrophysics Tech ○ ❪𖣐₃❫ Astronomy Software ○ ❪𖣐₃❫ Spectral Fitting Software ○ CIAO ○˒ HEASoft ○˒ ixpeobssim ○˒