Feeding the Void: Co-evolution of the SIDM-seeded Black Hole and the dark halo after core-collapse
Abstract
While the gravothermal collapse of self-interacting dark matter (SIDM) halos provides a compelling mechanism for seeding supermassive black holes (BHs), the post-collapse macroscopic co-evolution of the BH and its host halo remains largely unexplored. In this paper, we introduce a novel N-body framework to dynamically model the dark matter accretion onto the central BH. By bracketing the accretion rate with two complementary phenomenological schemes---a `multi-round core-collapse' scenario and a `continuous accretion' scenario---we establish bounds on the BH mass growth trajectory. We find that the BH mass reaches 5%−12% of the total halo mass within ≲2 Gyr post-collapse. Concurrently, this sustained mass depletion drives a `gravothermal supply chain' that forces outer dark matter inward, severely depleting the inner halo density (≲ 2rs). This unique structural imprint qualitatively matches the recently detected anomaly in the strong lens JVAS B1938+666 (detection V), where the best-fit lens model consists of an unresolved central point mass and a shallow, uniform-surface-density extended disk, offering a distinct observational signature for SIDM-seeded BHs.
Related
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BibTeX
@misc{zeng2026feeding,
title = {{Feeding the Void: Co-evolution of the SIDM-seeded Black Hole and the dark halo after core-collapse}},
author = {Zhichao Carton Zeng and Annika H. G. Peter and Louis E. Strigari and Andrew Benson and Xiaolong Du and Charlie Mace},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.22758},
eprint = {2609.22758},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.22758},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Feeding the Void: Co-evolution of the SIDM-seeded Black Hole and the dark halo after core-collapse
AU - Zhichao Carton Zeng
AU - Annika H. G. Peter
AU - Louis E. Strigari
AU - Andrew Benson
AU - Xiaolong Du
AU - Charlie Mace
PY - 2026
DA - 2026/09/19
PB - arXiv
DO - 10.48550/arxiv.2609.22758
UR - https://arxiv.org/abs/2609.22758
AB - While the gravothermal collapse of self-interacting dark matter (SIDM) halos provides a compelling mechanism for seeding supermassive black holes (BHs), the post-collapse macroscopic co-evolution of the BH and its host halo remains largely unexplored. In this paper, we introduce a novel N-body framework to dynamically model the dark matter accretion onto the central BH. By bracketing the accretion rate with two complementary phenomenological schemes---a `multi-round core-collapse' scenario and a `continuous accretion' scenario---we establish bounds on the BH mass growth trajectory. We find that the BH mass reaches 5%−12% of the total halo mass within ≲2 Gyr post-collapse. Concurrently, this sustained mass depletion drives a `gravothermal supply chain' that forces outer dark matter inward, severely depleting the inner halo density (≲ 2r_s). This unique structural imprint qualitatively matches the recently detected anomaly in the strong lens JVAS B1938+666 (detection V), where the best-fit lens model consists of an unresolved central point mass and a shallow, uniform-surface-density extended disk, offering a distinct observational signature for SIDM-seeded BHs.
ER -