An Etymological Dictionary of Astronomy and Astrophysics
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An intense discharge of → gamma rays, which range in duration from tenth of a second to tens of seconds and occur from sources widely distributed over the sky. The radio wave → afterglow from the → burst can last more than a year, making long-term observations of the sources possible. The favored hypothesis is that they are produced by a relativistic jet created by the merger of two → compact objects (specifically two → neutron stars or a neutron star and a → black hole). Mergers of this kind are also expected to create significant quantities of neutron-rich radioactive species, whose decay should result in a faint → transient, known as a → kilonova, in the days following the burst. Indeed, it is speculated that this mechanism may be the predominant source of stable → r-process elements in the Universe. Recent calculations suggest that much of the kilonova energy should appear in the → near-infrared spectral range, because of the high optical opacity created by these heavy r-process elements (Tanvir et al., 2017, Nature 500, 547).

→ gamma rays; → burst.