Gravitational-wave candidate
S251117dq
Two black holes almost certainly merged about 8.8 billion light-years away.
This line is written from the event's own fields, not translated from the source.
Each field explained
- Status
- Preliminary
An automatic alert sent within minutes of the signal. Later analysis can change these numbers, confirm the event with a GW name, or withdraw it.
- Significance
- High significance
Significant: it passed the bar for a public alert, so astronomers were asked to look for light from it.
- What it was
- Two black holes> 99.9%
- Noise in the detectors< 0.1%
- A neutron star and a black hole< 0.1%
- Two neutron stars< 0.1%
How likely each kind of source is, from the latest public alert. The numbers come from how the signal looked, not from a person's judgement.
- Distance
- About 8.8 billion light-years (2,700 ± 860 megaparsecs)
Estimated from how loud the signal was: a quieter wave came from further away. The spread is large in a first alert, and it shrinks as the analysis is refined.
- False alarm rate
- About once every 5.4 million years
How often noise alone would make a signal at least this strong. The rarer, the more likely it is real.
- Detectors
- LIGO Hanford and LIGO Livingston
The observatories that saw the signal. More detectors means a better position on the sky.
- When
When the signal reached Earth, in UTC.
- Latest alert
- Update
Each alert replaces the numbers of the one before it.