Pulsar Timing Arrays Paired with Astrometry Improve Nanohertz Gravitational Wave Sensitivity 10-50 Percent
PTA-astrometry joint analysis yields a measurable sensitivity gain for the nanohertz gravitational wave background while simultaneously probing Milky Way dynamics. The improvement arises from complementary spatial and temporal correlation signatures that neither probe captures alone. Future combined datasets from SKAO and upcoming astrometric missions will therefore deliver tighter limits on both cosmology and galactic structure than either instrument achieves independently.
The paper models the common gravitational wave background signal that produces both pulse arrival-time delays in millisecond pulsars and apparent angular deflections in stellar positions. SKAO alone is forecast to reach a characteristic strain sensitivity near 2 times 10 to the minus 15 at 1 per year; adding Gaia-like or future astrometric catalogs supplies an independent spatial correlation pattern that breaks degeneracies with intrinsic red noise and improves overall detection significance. Cross-instrument covariance also constrains the local galactic gravitational potential, revealing whether the observed signal is purely cosmological or partly sourced by nearby supermassive black hole binaries.
SKAO PTA team: combined PTA-astrometry pipeline will report a 3-sigma detection threshold crossed before 2032 if the background amplitude exceeds 1.5 times 10 to the minus 15.
Sources (3)
- [1]Primary Source(https://arxiv.org/abs/2606.24992)
- [2]Supporting Source(https://arxiv.org/abs/2306.16213)
- [3]Supporting Source(https://iopscience.iop.org/article/10.3847/2041-8213/acdac6)