2026-06-10 バージニア工科大学（Virginia Tech）
An artist’s impression of the environment close to a supermassive black hole, where only visible matter is shown. A new study suggests that the black hole might also be surrounded by a spherical halo of invisible dark matter. Illustration courtesy of Adobe Stock.
＜関連情報＞
- https://news.vt.edu/articles/2026/06/science-dark-matter-black-holes.html
- https://journals.aps.org/prd/abstract/10.1103/llpr-gnmh
AGN残響マッピングを用いた超大質量ブラックホール周辺の暗黒物質密度プロファイルの追跡に関する新しい手法 Novel method to trace the dark matter density profile around supermassive black holes with AGN reverberation mapping
Mayank Sharma, Gonzalo Herrera, Nahum Arav, and Shunsaku Horiuchi
Physical Review D Published: 24 February, 2026
DOI: https://doi.org/10.1103/llpr-gnmh
Abstract
We propose a new method to determine the dark matter density profile in the vicinity of distant supermassive black holes (SMBHs) using reverberation mapping (RM) measurements of active galactic nuclei (AGN). The mapping of multiple emission lines allows the measurement of the enclosed mass within different radii from the central SMBH, which can be used to infer or constrain the dark matter density profile on subparsec scales. We apply a toy model based on this method to a sample of 14 AGN to test its feasibility based on current measurements. We find that, for five objects, the observed enclosed mass does grow with radii, hinting toward the presence of a dark matter component at the 1−2 level. For these sources, we find global evidence for a universal dark matter profile with a preferred radial steepness of index ∼1.6, consistent with the scenario expected for a dark matter spike mildly relaxed by stellar heating processes. The enclosed dark matter mass, however, is found to be significantly larger than expected. We show that the current RM-based mass measurements suffer from large systematic uncertainties that limit the effectiveness of our method. Our work emphasizes the importance of applying the recent developments in mass determination techniques to target multiple emission lines with future RM and interferometry campaigns. This provides the most direct way of constraining the dark matter density in the subparsec regions around extragalactic SMBHs, which is crucial to our understanding of the dynamics and nature of dark matter.
