The researchers were equally intrigued to discover that millimeter-wave radiation mimics the emission pattern of gamma rays.
Both electrons and protons may contribute to the gamma ray afterglow detected by GRO, Kundu says.
During that time, protons andelectrons that leak out of the trap can rain down upon atoms in the chromosphere and spark the emission of gamma rays, he says.
Although the core of this compact object has roughly the diameter of the solar system, its gamma ray output is about 10 million times the sun's total luminosity at all wavelengths, researchers say,
Using ground-based telescopes that detect visible light produced when high-energy gamma rays self-destruct in Earth's atmosphere, astronomers had previously examined likely extragalactic sources of this radiation, including quasars and active galaxies.
Though the data suggested that Markarian 421 was not the most intense high-energy gamma ray emitter among the 14 Sources GRO had identified, that galaxy does reside closest to Earth.
In a commentary accompanying the NATURE article, Francis Halzen of the University of Wisconsin-Madison says that Markarian's gamma ray output suggests that the galaxy may emit an even higher intensity of elusive subatomic particles called neutrinos.
Data gathered by another GRO instrument, the Energetic Gamma
-Ray Experiment Telescope, show that three previously discovered quasars are spewing so many gamma
rays that each quasar emits about 10 million to 100 million times the total gamma
-ray output of the Milky Way, reports Carl E.
Most are charged particles (ions), while a tiny minority encompass energetic, uncharged particles of light - photons called gamma rays.
Rosenberg, searching for cosmic rays - particularly high-energy gamma rays - is now uniting astronomers and particle physicists in a common pursuit.
In fact, since 1988 researchers have puzzled over observations that suggest very-high-energy gamma rays have properties similar to energetic ions.
Gamma rays make up less than one-hundredth of 1 percent of all high-energy cosmic rays, particles associated primarily with such exotic objects as neutron stars, supernovas, quasars, exploding galaxies and the long-sought black holes.
Protheroe state that their installation in Buckland Park, South Australia, is probably the only one located so as to be able to record showers caused by gamma
rays from SN 1987A.