Gravitational Acceleration of Dark Matter by Black Holes at the Center of the Milky Way ✛ ✎ ✦
Context
The detection of dark matter, first proposed by Fritz Zwicky to explain the motion of galaxies in clusters, remains one of the key challenges of modern physics. Although direct detection experiments like LZ, XENONnT, and DarkSide-50 have achieved impressive sensitivity, their ability to register light dark matter is limited by the low velocities of particles in the galactic halo. However, it has recently been realized that binary black holes can serve as natural accelerators, boosting dark matter via gravitational slingshot. Of particular interest is the nuclear star cluster at the center of our Galaxy, where Sagittarius A*, a supermassive black hole with a mass of about 4 million solar masses, is surrounded by a swarm of tens of thousands of stellar-mass black holes. The high density of dark matter and extreme gravitational potential make this region an ideal factory of fast dark matter. Detailed observations by Vera Rubin and others confirmed the presence of hidden mass in galaxies.
Methods
To estimate the flux of accelerated dark matter, the authors applied numerical simulation of the restricted three-body problem using the Verlet algorithm. In each simulation, a dark matter particle was injected into the sphere of influence of a system of two black holes, and its trajectory was calculated taking into account Newtonian gravity and energy conservation. The orbits of the black holes were prescribed based on a power-law Bahcall–Wolf profile, consistent with observational data on star formation and metallicity in the Galactic center, and the population was modeled taking into account stellar evolution. The distribution of dark matter was described by a Navarro–Frenk–White profile with a correction for gravitational focusing by Sagittarius A*. To account for all possible initial conditions, the phase space of orbits was binned, and for each bin the differential ejection spectrum was calculated. The use of angular momentum conservation and Jeans theorem allowed linking the orbital distribution with the density of black holes.
Results
The results of the simulation showed that black holes in the nuclear star cluster can eject dark matter at speeds up to 25,000 km/s, with the main contribution to the high-energy tail coming from only a few tens of black holes on short-period orbits. The integral ejection spectrum exceeds the flux from any other known galactic sources of accelerated dark matter. Remarkably, even under conservative assumptions about the density profile of dark matter, large-volume detectors gain sensitivity to masses down to 60 MeV for elastic scattering, and for inelastic processes with masses on the order of TeV, splittings up to 9 MeV become accessible. Calculations also demonstrate that a single intermediate-mass black hole on a close orbit can produce a comparable effect.
Implications
This result means that dark matter can be detected in experiments that were not originally optimized for low masses. Black holes at the center of the Galaxy become a new tool of particle astrophysics, independent of specific interaction models. Detecting a signal from such a flux would not only confirm the existence of dark matter, but also probe the distribution of black holes near the supermassive black hole and the structure of the galactic center.
Future development
In the future, with the commissioning of new gravitational-wave observatories, such as LISA, independent mapping of the population of black holes near Sagittarius A* will become possible. This will allow refining predictions of accelerated dark matter fluxes and possibly discovering correlations between gravitational-wave events and signals in dark matter detectors. Additionally, improving detectors and scaling to multi-ton scales will open the way to studying a wide class of inelastic dark matter models.
Impact
The discovery will impact both particle physics, providing a new way to search for dark matter without being tied to specific masses and interaction constants, and the dynamics of galaxies, highlighting the role of nuclear clusters in redistributing dark matter.
Next steps
The next step is to include in the calculations bound states of dark matter around Sagittarius A* and to account for mass segregation effects, which could further increase the flux of fast particles. Also planned is a detailed study of the possibility of registering such events with neutrino observatories.
Key open problems
This work is directly connected to unresolved questions about the nature of dark matter, the distribution of black holes at the center of the Galaxy, and the mechanisms of formation of galactic nuclei. The success of the proposed approach could shed light on the long-standing problem of "cusps" in the density profiles of dark matter.
The knowledge machine's view
This section is addressed to the author of the paper and their colleagues. Neighbouring works were found by meaning-based search across our archive, not by word overlap. We do not review: we show the field around the work.
What the work does
The study examines how stellar-mass black holes in the Milky Way's nuclear star cluster can gravitationally accelerate dark matter particles. Using numerical simulations of the restricted three-body problem and accounting for orbital distributions, it is found that the velocities of ejected dark matter reach 25,000 km/s, and the main contribution to the high-energy tail comes from a few dozen black holes.
Where its strength is
The strength of the work lies in its specific quantitative estimate of the flux of accelerated dark matter from compact objects at the Galactic center, linking the dynamics of the nuclear cluster to the possibilities of direct detection.
Where it could go next
- It might be interesting to compare the obtained velocities with the characteristics of particles accelerated near the supermassive black hole, as in the work on the cosmic accelerator.based on: Cosmic Accelerator: How a Black Hole Boosts Particles arXiv:2607.20209
- Closely related is the study of particle acceleration in black hole binary systems; perhaps their modeling approach could help refine the contribution of such systems to the overall flux.based on: The Acceleration of Invisible Pairs: What the Dance of Black Holes Reveals arXiv:2606.28156
- It would be interesting to see how the wind from the black hole at the Galactic center affects the distribution of dark matter and, consequently, the efficiency of its acceleration.based on: Black Hole Wind Clears the Galactic Center arXiv:2509.10615
Worth trying
- Test a combined treatment of particle acceleration from both binary black holes and the supermassive black hole.
- Investigate how a wind from the central black hole changes the dark matter density in the acceleration zone.
- Compare predicted spectra with constraints from gamma-ray observations of the Galactic center.
Why this may matter
If fast dark matter indeed exists, it would open a new window for direct detection even at low particle masses, and also allow linking the dynamics of the Galactic center to signals in terrestrial experiments.
Nearby works in our archive
- Invisible Conductors of Galactic Diskssimilarity 0.67
- Gamma Glow at the Galactic Center: Not Annihilation, but Collisionssimilarity 0.63
- An X-ray Snowstorm Around a Black Holesimilarity 0.63
- The Acceleration of Invisible Pairs: What the Dance of Black Holes Revealssimilarity 0.63
- Excess Gamma Light from the Galactic Centersimilarity 0.63
- Black Hole Wind Clears the Galactic Centersimilarity 0.62
- Cosmic Accelerator: How a Black Hole Boosts Particlessimilarity 0.62
The closest work in the archive sits at 0.67 by meaning — the usual level for our corpus.
Although at the center of the Galaxy the density of dark matter can be thousands of times higher than locally, the accelerated particles reaching Earth originate from an infinitesimally small fraction — only those that found themselves "on the wrong orbit" too close to black holes.
In the movie "Interstellar," the heroes use a gravitational maneuver around the black hole Gargantua to save fuel. In reality, black holes at the center of our Galaxy can act as giant slingshots, accelerating dark matter to near-light speeds.
Key numbers
- maximum ejection velocity: ~25,000 km/s
- number of black holes in the nuclear cluster: ~2.5×105
- distance from Earth to the Galactic center: ~8.2 kpc
- achieved dark matter mass for xenon detectors: ~60 MeV
- maximum mass splitting for inelastic scattering: up to 9 MeV