Cosmic X-ray source

A cosmic X-ray source is an astronomical emitter detected through its X-rays. Hot plasma, energetic particles and matter falling into deep gravitational potentials can produce such radiation, so detection alone does not identify a black hole or one unique emission mechanism.

A useful observation proceeds from an excess of detector events to a sky location, spectrum and light curve. Background rejection and response calibration determine which incident photons could have produced those events. The 1962 rocket discovery of cosmic X-ray sources illustrates how a scanning detector and an independent orientation measurement can establish a celestial signal without forming an ordinary optical image.