Scalar Field Model for Dark Matter Spikes Surrounding Sgr A* and M87*
Abstract
Theoretical models suggest that the adiabatic growth of a black hole immersed in dark matter can lead to the formation of high density regions of dark matter, known as ``spikes'', near the black hole event horizon. The density of these spikes is determined theoretically and observationally to be a power law of the form ρ(r) ∝ r−γsp. It has been shown that the spike can potentially have a detectable impact on the emitted gravitational waves and shadow radius of the central black hole. In this work, we model the dark matter spike using a real scalar field with a non-standard potential. More specifically we ``reverse engineer'' the equations of motion to find a potential for the scalar field that permits a solution to the equations of motion with desired energy density and reasonable background geometry. We show that the emerging geometry is testable. In addition, the fact that the solution is derived from a covariant action makes it possible to study gravitational perturbations of the black hole in the presence of a spike including the backreaction of the spike.
Related
- Scalar wave dark matter imprints on binary black hole mergers: dependence on field mass and density
- Revisiting bounds on neutrino dark matter interaction at spikes
- Resonant neutrino flavor conversion within dark matter spikes
- Population search for dark matter spikes in megamaser rotation curves
- The Irreversible Depletion of Dark Matter Spikes by Extreme-Mass-Ratio Inspirals
BibTeX
@misc{daghigh2026scalar,
title = {{Scalar Field Model for Dark Matter Spikes Surrounding Sgr A$^*$ and M87$^*$}},
author = {Ramin G. Daghigh and Michael D. Green and Gabor Kunstatter},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.01900},
eprint = {2609.01900},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.01900},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Scalar Field Model for Dark Matter Spikes Surrounding Sgr A^* and M87^*
AU - Ramin G. Daghigh
AU - Michael D. Green
AU - Gabor Kunstatter
PY - 2026
DA - 2026/09/01
PB - arXiv
DO - 10.48550/arxiv.2609.01900
UR - https://arxiv.org/abs/2609.01900
AB - Theoretical models suggest that the adiabatic growth of a black hole immersed in dark matter can lead to the formation of high density regions of dark matter, known as ``spikes'', near the black hole event horizon. The density of these spikes is determined theoretically and observationally to be a power law of the form ρ(r) ∝ r^−γ_sp. It has been shown that the spike can potentially have a detectable impact on the emitted gravitational waves and shadow radius of the central black hole. In this work, we model the dark matter spike using a real scalar field with a non-standard potential. More specifically we ``reverse engineer'' the equations of motion to find a potential for the scalar field that permits a solution to the equations of motion with desired energy density and reasonable background geometry. We show that the emerging geometry is testable. In addition, the fact that the solution is derived from a covariant action makes it possible to study gravitational perturbations of the black hole in the presence of a spike including the backreaction of the spike.
ER -