Multi-messenger astronomy

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.

The main multi-messenger sources outside the heliosphere are: 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. Lack of any electromagnetic counterpart, for example, could be evidence in support of the remnant being a black hole.