Study Proposes Dark Matter Core at Milky Way's Center
New research suggests that the Milky Way's central mass may be a dense dark matter core rather than a supermassive black hole.
Recent research challenges the prevailing belief that a supermassive black hole, known as Sagittarius A*, resides at the center of the Milky Way. Instead, scientists propose that the galaxy's core may consist of an ultra-dense form of dark matter, capable of replicating the gravitational effects attributed to a black hole.
This hypothesis addresses longstanding discrepancies in galactic physics. Observations of stars, particularly the S-stars, orbiting near the galactic center at high velocities have traditionally been explained by the presence of a massive black hole. However, at greater distances, the galaxy's rotation curve, as measured by the European Space Agency's Gaia mission, exhibits a decline in orbital speeds, suggesting a different mass distribution.
The research team modeled a concentration of fermionic dark matter—particles that adhere to quantum rules preventing indefinite compression. Their model produces a compact core that can account for the rapid orbits of S-stars and nearby dust-enshrouded objects, while the surrounding halo explains the observed decrease in rotation speeds at larger distances.
Additionally, simulations indicate that such a dense dark matter core could produce a shadow-like feature resembling the image of Sagittarius A* captured by the Event Horizon Telescope, even without an event horizon.
If confirmed, this model would unify the understanding of the Milky Way's central mass and its dark matter halo, suggesting they are manifestations of the same continuous substance. This could reshape interpretations of black hole candidates in other galaxies and inform future studies on the nature of dark matter.
The study emphasizes the need for more precise data, particularly from stars closer to the galactic center, to distinguish between the black hole and dark matter core scenarios. Future observations with instruments like the GRAVITY interferometer and the Event Horizon Telescope will be crucial in testing this hypothesis.
The findings are published in the Monthly Notices of the Royal Astronomical Society.