Multi-messenger astronomy

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

Detection from one messenger and non-detection from a different messenger can also be informative.[4]

Networks

The

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.

Milestones

• 1940s: Some cosmic rays are identified as forming in solar flares.^[5]
• 1987: Supernova
  Kamiokande-II, IMB and Baksan
  neutrino observatories, a couple of hours before the supernova light was detected with optical telescopes.
• August 2017: A
  Dark Energy Camera. Ultraviolet observations by the Neil Gehrels Swift Observatory, X-ray observations by the Chandra X-ray Observatory and radio observations by the Karl G. Jansky Very Large Array complemented the detection. This was the first gravitational wave event observed with an electromagnetic counterpart, thereby marking a significant breakthrough for multi-messenger astronomy.^[14] Non-observation of neutrinos was attributed to the jets being strongly off-axis.^[15] In October 2020, astronomers reported lingering X-ray emission from GW170817/GRB 170817A/SSS17a.^[16]
• September 2017 (announced July 2018): On September 22, the extremely-high-energy
  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 blazar TXS 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 event AT2019dsg 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]
• June 2023: Astronomers used a new cascade neutrino technique^[30] to detect, for the first time, the release of neutrinos from the galactic plane of the Milky Way galaxy, creating the first neutrino-based galactic map.^[31][32]

References