Independent Algorithm Confirms M87* Ring at 42.2 μas, Supporting 6.5 Billion-Solar-Mass Black Hole
Updated
Updated · Nature.com · Nov 11
Independent Algorithm Confirms M87* Ring at 42.2 μas, Supporting 6.5 Billion-Solar-Mass Black Hole
3 articles · Updated · Nature.com · Nov 11
Summary
A new analysis of Event Horizon Telescope data from 2017, 2018 and 2021 independently recovered M87* as a compact ring-like shadow, reinforcing the original black hole image against past challenges to its morphology.
Using a calibration-insensitive GenDIReCT algorithm built on closure invariants rather than hand-tuned imaging priors, researchers found the ring persisted across multiple observing epochs and reconstruction fields of view.
The reconstructed ring measured 42.2 ± 1.5 microarcseconds across, while separate geometric modeling gave 42.3 ± 1.1 microarcseconds, both consistent with earlier EHT results.
That diameter implies a black hole mass of 6.5 ± 0.5 billion solar masses at M87's center, matching stellar-dynamics estimates better than the smaller mass inferred from gas-dynamics measurements.
Comparisons with simulated images also favored a viewing inclination near 20° from the approaching jet, while the study said current image-domain analysis still cannot pin down M87*'s spin.