11 Gamma Ray

図 11: Gamma-Ray

Intensity of high-energy gamma-ray emission observed by the Energetic Gamma-Ray Experiment Telescope (EGRET) instrument on the Compton Gamma-Ray Observatory (CGRO). The image includes all photons with energies greater than 300 MeV. At these extreme energies, most of the celestial gamma rays originate in collisions of cosmic rays with hydrogen nuclei in interstellar clouds. The bright, compact sources near Galactic longitudes 185°, 195°, and 265° indicate high-energy phenomena associated with the Crab, Geminga, and Vela pulsars, respectively.

$$\nu > 2.4 \times 10^{13} {\rm GHz} ,\quad \lambda < 1.24914 \times 10^{-14} {\rm m}= 1.24914 \times 10^{-4} {\rm\AA}$$