| Event type | Gamma-ray burst |
|---|---|
| Date | c. 5.5 billion years ago (detected 25 December 2010 4:59 18:38 UTC) |
| Duration | c. 28 minutes |
| Constellation | Andromeda |
| Right ascension | 00h 00m 47.51s |
| Declination | +44° 36′ 01.1″ |
| Distance | c. 5.5 billion ly |
| Redshift | 0.33 |
| Other designations | GRB 101225A |
GRB 101225A, also known as the "Christmas burst", was a cosmic explosion first detected by NASA's Swift observatory on Christmas Day 2010. The gamma-ray emission lasted at least 28 minutes, which is unusually long. Follow-up observations of the burst's afterglow by the Hubble Space Telescope and ground-based observatories were unable to determine the object's distance using spectroscopic methods.
In papers published in the journal Nature, two different groups of astronomers proposed different theories about the event's origin. Sergio Campana's group proposes that the event was caused by a comet crashing onto a neutron star within our own galaxy. Christina Thöne's group prefers a more conventional supernova mechanism, involving a merger between a helium star and a neutron star at a distance of about 5.5 billion light years from Earth.