X ra - zone
- X ray absorption
- X ray astronomy
- X ray background
- X ray binary stars
- X ray bright points
- X ray bursts
- X ray continuum
- X ray detectors
- X ray diffraction
- X ray emission
- X ray flares
- X ray fluorescence
- X ray identifications
- X ray lines
- X ray luminosity
- X ray maps
- X ray novas
- X ray observatories
- X ray polarization
