Simulations Put Milky Way's Stellar-Mass Black Holes at 170 Million, Mapping a 790-Parsec Disk
Updated
Updated · ScienceAlert · Aug 2
Simulations Put Milky Way's Stellar-Mass Black Holes at 170 Million, Mapping a 790-Parsec Disk
3 articles · Updated · ScienceAlert · Aug 2
Summary
Astronomers modeled the Milky Way’s 13.6-billion-year history and estimated the galaxy now contains about 170 million stellar-mass black holes, most of them invisible unless actively feeding.
The simulations also predict where those remnants should be found: near the Sun’s orbit, the density is roughly one black hole per 6,250 cubic parsecs, making nearby finds unlikely.
A key result is a much thicker black-hole layer than the Milky Way’s stellar thin disk—about 790 parsecs versus 306 parsecs—because asymmetric supernovae can kick newborn black holes far from their birthplaces.
The lightest black holes appear to travel farthest from the galactic plane, while heavier ones stay closer, a pattern the team says could help future surveys test competing models of supernova explosions and black-hole formation.
The study, led by Tom Wagg of the Flatiron Institute, is posted on arXiv and submitted to AAS journals, with upcoming observations expected to test whether the galaxy’s hidden black-hole population preserves a record of its past.