The diffuse supernova neutrino background (DSNB) is a theoretical population of
neutrino
A neutrino ( ; denoted by the Greek letter ) is a fermion (an elementary particle with spin of ) that interacts only via the weak interaction and gravity. The neutrino is so named because it is electrically neutral and because its rest mass ...
s (and anti-neutrinos) cumulatively originating from all of the supernovae events which have occurred throughout the Universe.
Sources
An individual supernova will release as many as
neutrinos
A neutrino ( ; denoted by the Greek letter ) is a fermion (an elementary particle with spin of ) that interacts only via the weak interaction and gravity. The neutrino is so named because it is electrically neutral and because its rest mass is ...
, which is detectable as a short burst of events on Earth provided that the supernova occurred close by enough: Within our own galaxy or one of its
satellite galaxies
A satellite galaxy is a smaller companion galaxy that travels on bound orbits within the gravitational potential of a more massive and luminous host galaxy (also known as the primary galaxy). Satellite galaxies and their constituents are bound ...
, the only current example of which is
SN1987A
SN 1987A was a type II supernova in the Large Magellanic Cloud, a dwarf satellite galaxy of the Milky Way. It occurred approximately from Earth and was the closest observed supernova since Kepler's Supernova. 1987A's light reached Earth on Febr ...
.
In contrast the DSNB is a continuous source of neutrino events for which currently only experimental upper limits exist e.g. from the
Super Kamiokande
Super-Kamiokande (abbreviation of Super-Kamioka Neutrino Detection Experiment, also abbreviated to Super-K or SK; ja, スーパーカミオカンデ) is a Neutrino detector, neutrino observatory located Kamioka Observatory, under Mount Ikeno ...
experiment at a level of
for neutrino energies above 17.3 MeV.
Predicted detections
Theoretical predictions for the flux of the DSNB on Earth are difficult as they depend on many different parameters and assumptions e.g. the rate of supernovae events in the Universe as a function of time, the star formation rate, and the neutrino spectrum from each supernova.
However even given these uncertainties the DSNB flux should not be more than an order of magnitude below the current experimental bound, and so will be detectable in the near future.
See also
*
Cosmic neutrino background
The cosmic neutrino background (CNB or CB) is the universe's background particle radiation composed of neutrinos. They are sometimes known as relic neutrinos.
The CB is a relic of the Big Bang; while the cosmic microwave background radiation (CM ...
References
Supernovae
Neutrino astronomy
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