Little Red Dots as a Transient Phase of Self-Interacting Dark Matter Assisted Black Hole Growth
Abstract
The discovery of Little Red Dots (LRDs) with JWST has revealed a population of compact, red galaxies hosting rapidly growing black holes at early cosmic times. Their compact morphologies, broad emission lines, weak X-ray emission, and distinctive V-shaped spectral energy distributions indicate a short-lived phase of black-hole growth within a dense nuclear environment. Here we propose that LRDs arise from a transient episode of self-interacting dark matter (SIDM)-assisted black-hole growth during galaxy assembly. In this scenario, gas inflows first establish a compact nuclear thick disk, which modifies the central SIDM distribution and provides the obscuring structure around the accreting black hole. Once the SIDM density near the seed black hole becomes sufficiently enhanced, rapid SIDM accretion drives a major increase in black-hole mass, initiating the transient LRD phase. The resulting obscured growth phase naturally suppresses direct short-wavelength emission and redistributes the radiation field, producing the red continuum and V-shaped spectral signatures of LRDs. This framework links gas inflow, SIDM dynamics, and early black-hole assembly, predicting that LRDs preferentially occur in galaxies undergoing strong nuclear inflow and evolve into ordinary AGN after this transient phase. Unlike models that require globally rare halo histories, long super-Eddington gas growth, or purely phenomenological obscuration, our model ties the overmassive black hole, X-ray weakness, spectral shape, and finite duty cycle to one local gas-triggered SIDM event.
Related
- Rapid Dark Growth of Seed Black Holes in Self-Interacting Dark Matter
- Cosmology of self-interacting ultralight dark matter: simultaneous shifts in the Hubble constant and structure growth
- Self-interacting dark matter delays bar growth in an isolated gas-rich galactic disk: torque-resolved numerical evidence
- Weighing Little Red Dots with Transient Events
- Strong-lensing perturber signatures in self-interacting dark matter simulations
BibTeX
@misc{rong2026little,
title = {{Little Red Dots as a Transient Phase of Self-Interacting Dark Matter Assisted Black Hole Growth}},
author = {Yu Rong and Shuang-Nan Zhang and Jian-Min Wang and Junxian Wang and Zhicheng He},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.20021},
eprint = {2609.20021},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.20021},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Little Red Dots as a Transient Phase of Self-Interacting Dark Matter Assisted Black Hole Growth
AU - Yu Rong
AU - Shuang-Nan Zhang
AU - Jian-Min Wang
AU - Junxian Wang
AU - Zhicheng He
PY - 2026
DA - 2026/09/17
PB - arXiv
DO - 10.48550/arxiv.2609.20021
UR - https://arxiv.org/abs/2609.20021
AB - The discovery of Little Red Dots (LRDs) with JWST has revealed a population of compact, red galaxies hosting rapidly growing black holes at early cosmic times. Their compact morphologies, broad emission lines, weak X-ray emission, and distinctive V-shaped spectral energy distributions indicate a short-lived phase of black-hole growth within a dense nuclear environment. Here we propose that LRDs arise from a transient episode of self-interacting dark matter (SIDM)-assisted black-hole growth during galaxy assembly. In this scenario, gas inflows first establish a compact nuclear thick disk, which modifies the central SIDM distribution and provides the obscuring structure around the accreting black hole. Once the SIDM density near the seed black hole becomes sufficiently enhanced, rapid SIDM accretion drives a major increase in black-hole mass, initiating the transient LRD phase. The resulting obscured growth phase naturally suppresses direct short-wavelength emission and redistributes the radiation field, producing the red continuum and V-shaped spectral signatures of LRDs. This framework links gas inflow, SIDM dynamics, and early black-hole assembly, predicting that LRDs preferentially occur in galaxies undergoing strong nuclear inflow and evolve into ordinary AGN after this transient phase. Unlike models that require globally rare halo histories, long super-Eddington gas growth, or purely phenomenological obscuration, our model ties the overmassive black hole, X-ray weakness, spectral shape, and finite duty cycle to one local gas-triggered SIDM event.
ER -