Multi-messenger astronomy is the coordinated observation and interpretation of multiple signals received from the same astronomical event. Many types of cosmological events involve complex interactions between a variety of astrophysical processes, each of which may independently emit signals of a characteristic "messenger" type: electromagnetic radiation (including infrared, visible light and X-rays), gravitational waves, neutrinos, and cosmic rays. When received on Earth, identifying that disparate observations were generated by the same source can allow for improved reconstruction or a better understanding of the event, and reveals more information about the source.
Detection from one messenger and non-detection from a different messenger can also be informative.[4] Lack of any electromagnetic counterpart, for example, could be evidence in support of the remnant being a black hole.
The Astrophysical Multimessenger Observatory Network (AMON),[12] created in 2013,[13] 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.
1987: Supernova SN 1987A emitted neutrinos that were detected at the Kamiokande-II, IMB and Baksan neutrino observatories, a couple of hours before the supernova light was detected with optical telescopes.
September 2017 (announced July 2018): On September 22, the extremely-high-energy[17] (about 290 TeV) neutrino event IceCube-170922A[18] was recorded by the IceCube Collaboration,[19][20] which sent out an alert with coordinates for the possible source. The detection of gamma rays above 100 MeV by the Fermi-LAT Collaboration[21] and between 100 GeV and 400 GeV by the MAGIC Collaboration[22] from the blazarTXS 0506+056 (reported September 28 and October 4, respectively) was deemed positionally consistent with the neutrino signal.[23] The signals can be explained by ultra-high-energy protons accelerated in blazar jets, producing neutral pions (decaying into gamma rays) and charged pions (decaying into neutrinos).[24] This is the first time that a neutrino detector has been used to locate an object in space and a source of cosmic rays has been identified.[23][25][26][27][28]
October 2019 (announced February 2021): On October 1, a high energy neutrino was detected at IceCube and follow-up measurements in visible light, ultraviolet, x-rays and radio waves identified the tidal disruption eventAT2019dsg as possible source.[10]
November 2019 (announced June 2022): A second high energy neutrino detected by IceCube associated with a tidal disruption event AT2019fdr.[29]
^ abAartsen; et al. (The IceCube Collaboration, Fermi-LAT, MAGIC, AGILE, ASAS-SN, HAWC, H.E.S.S., INTEGRAL, Kanata, Kiso, Kapteyn, Liverpool Telescope, Subaru, Swift/NuSTAR, VERITAS, VLA/17B-403 teams) (12 July 2018). "Multimessenger observations of a flaring blazar coincident with high-energy neutrino IceCube-170922A". Science. 361 (6398): eaat1378. arXiv:1807.08816. Bibcode:2018Sci...361.1378I. doi:10.1126/science.aat1378. PMID30002226. S2CID49734791.
^De Angelis, Alessandro; Pimenta, Mario (2018). Introduction to particle and astroparticle physics (multimessenger astronomy and its particle physics foundations). Springer. doi:10.1007/978-3-319-78181-5. ISBN978-3-319-78181-5.
