Multi-messenger astronomy is astronomy based on the coordinated observation and interpretation of signals carried by disparate "messengers": electromagnetic radiation, gravitational waves, neutrinos, and cosmic rays. They are created by different astrophysical processes, and thus reveal different information about their sources.
The main multi-messenger sources outside the heliosphere are expected to be compact binary pairs (black holes and neutron stars), supernovae, irregular neutron stars, gamma-ray bursts, active galactic nuclei, and relativistic jets. The table below lists several types of events and expected messengers.
Detection from one messenger and non-detection from a different messenger can also be informative.
|Event type||Electromagnetic||Cosmic rays||Gravitational waves||Neutrinos||Example|
|Solar flare||yes||yes||-||-||SOL1942-02-28[failed verification]|
|Neutron star merger||yes||-||yes||predicted||GW170817|
|Blazar||yes||possible||-||yes||TXS 0506+056 (IceCube)|
|Active galactic nucleus||yes||possible||yes||Messier 77 (IceCube)|
|Tidal disruption event||yes||possible||possible||yes||AT2019dsg (IceCube)
The Supernova Early Warning System (SNEWS), established in 1999 at Brookhaven National Laboratory and automated since 2005, combines multiple neutrino detectors to generate supernova alerts. (See also neutrino astronomy).
The Astrophysical Multimessenger Observatory Network (AMON), created in 2013, is a broader and more ambitious project to facilitate the sharing of preliminary observations and to encourage the search for "sub-threshold" events which are not perceptible to any single instrument. It is based at Pennsylvania State University.
Kurahashi Neilson first came up with the idea to use cascade neutrinos to map the Milky Way in 2015.