Active galaxy. Artwork of an active spiral galaxy with jets seen emanating from its centre. Active galaxies are those which emit unusually large amounts of energy. The jets, which generally emerge from the nucleus at a right angle to the galaxy's plane, consist of electrons moving close to the speed of light. The interaction of these charged particles with the magnetic field of the galaxy produces emissions known as synchrotron radiation. This radiation is seen as optical radiation (light), as well as at other wavelengths. It is thought that the power sources for these high-energy phenomena are enormous black holes at the galaxies' centres.