Gamma rays (γ)

0.3 - 60 EHz 1 nm - 5 pm
...are mostly know as the waves that is emitted as a by-product of radioactive processes. They are at the top of the spectrum that humans can reproduce.
From this point forward, waves start to be very dangerous because they interact on the nuclei in atoms. TO_EDIT:There is no theoretical upper limit to the energies of gamma-ray photons and no lower limit to gamma-ray wavelengths; observed energies presently extend up to a few trillion electron volts—these extremely high-energy photons are produced in astronomical sources through currently unidentified mechanisms ---- few kiloelectronvolts (keV) to approximately 8 megaelectronvolts ( https://en.wikipedia.org/wiki/Gamma_ray ) corresponding to the typical energy levels in nuclei with reasonably long lifetimes

Sources:

A lot of things in space: super-/hypernovas (exploding (massive)stars), supernova remnants (caused by radio active decay), pulsars (fast spinning (600 rps) of huge objects), afterglow (cooling gasses), jets (result of black hole annihilations)
Nuclear power, radioactive material, particle accelerators

To one definition, the gamma ray band starts where EM radiation is due to nuclear events; another just takes an arbitrary wavelength of 10-11 m

Uses:

This band of the spectrum is most crowded with uses for 1001 devices such as:
Mobile phones, satellite communications, radar, TV, radio, medical PET scans..

Interaction with matter:

photoelectric effect, Compton scattering, pair production

Effects:

Kills or mutates living cells

Very-high-energy gamma rays

100 GeV - 100 TeV

Potential sources:

binary star, supernovae, active galactic nuclei, quasars, and gamma-ray burstsa

Interaction with matter:

Ultra-high-energy gamma rays

+ 100 TeV

Potential sources:

rapidly spinning neutron star, or 'pulsar', supernovae, active galactic nuclei, quasars, and gamma-ray bursts

Interaction with matter:

Cosmic Radiation

+ 10 MeV
They are actually not EM radiation, but particle radiation, although they are almost always companied by very and ultra high energy gamma radiation.
As of today, it's not certain which sources produce cosmic rays.

Potential sources:

supernovae, active galactic nuclei, quasars, and gamma-ray bursts

Interaction with matter:

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