SATLASGravitational waves · Ground
NANOGrav
North American Nanohertz Observatory for Gravitational Waves
OperatingOperating since 2007.
A pulsar timing arraypulsar timing arrayA set of millisecond pulsars timed for years. Nanohertz gravitational waves perturb pulse arrival times by nanoseconds, correlated between pulsar pairs in a specific way with their separation on the sky (the Hellings–Downs curve).: 67 millisecond pulsarspulsarA rotating, magnetised neutron star whose beamed emission sweeps past Earth once per turn. Millisecond pulsars, spun up by accretion, keep time to tens of nanoseconds over decades. in its 15-year data set, timed with the GBT, the VLA, CHIME and, until 2020, Arecibo. Its 15-year data set (2023) showed evidence (about 3–4σ) for the Hellings–Downs correlation expected from a nanohertz gravitational-wave background, most plausibly from supermassive black-hole binaries; EPTA, PPTA and CPTA reported consistent signals.
- Operator
- NSF, NANOGrav collaboration
- Site
- Radio telescopes including GBT, VLA and CHIME
- Frequency band
- 1 nHz – 100 nHz
- Messenger
- Gravitational waves
- Collaboration founded
- 2007
Frequency band
Gravitational-wave frequency, from pulsar timing arrays (nHz) through space interferometers (mHz) to ground-based detectors (kHz).
Sky coverage
The pulsars are spread across the sky, so the array is sensitive in all directions; sensitivity to individual sources follows their distribution.
Archives
Sources
Verified 15 November 2026.