Given current mass bounds and instrument sensitivities, which observation reaches a decisive confidence — and roughly when? Adjust the target sigma and watch the forecast update.
Gaia DR4 (expected ~2026): single-epoch proper-motion precision ~5 μas/yr at G=14. For ω Cen core stars (G≈16–18), degraded to ~30–80 μas/yr. DR4 extends the baseline to 10+ years — the key improvement.
Roman Space Telescope (launch 2027): 110 Mpx detector, 0.11 arcsec/px. With multi-epoch astrometry in ω Cen, precision ~10–30 μas/epoch. Discrimination threshold for the IMBH vs dark-cluster question is ~10 μas over 3 years.
ELT-MICADO (first light ~2028): 40m aperture with MCAO, delivered astrometric precision ~50–100 μas in crowded fields. Spatial resolution ~5 mas at K-band; resolves sub-parsec stellar orbits in ω Cen core.
LISA (launch ~2037): sensitivity to EMRIs (extreme mass-ratio inspirals). An IMBH of 8,200 M☉ with a stellar-mass BH companion at sub-pc separation produces an EMRI signal in the LISA band. Requires sufficient event rate in the cluster.
The discrimination target is resolving the 6,000–8,200 M☉ window. Each instrument's projected measurement precision is compared against the mass gap: once the precision (converted to equivalent mass uncertainty via the virial estimator σ ∝ M^0.5 at fixed distance) falls below half the gap, a detection at the target σ becomes feasible. Dates represent optimistic estimates assuming nominal mission performance.
These projections are model-dependent. Angular distance to ω Cen adopted from measurements.js: 5.2 kpc.