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 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.