Halo-driven Origin and Evolution of Overmassive Black Holes and Little Red Dots

Abstract

We present a theoretical model in which the recently detected overmassive black holes (OBHs), and potentially Little Red Dots (LRDs), arise during a halo-driven transient phase preceding the established coevolution of supermassive black holes (SMBHs) and their host galaxies. In this model, halo gravity drives an early phase of rapid black hole growth, leading to systems in high-redshift haloes that lie above the local scaling relations. As the halo evolves, a transition in halo thermodynamics leads to the onset of a hot, pressure-supported medium that suppresses accretion, reducing the black hole growth rate and driving the system toward the local black hole mass−stellar mass relation. LRDs may represent an observational manifestation of the rapid, halo-driven growth phase, while OBHs trace its direct mass signature. Our model thus provides a unified framework in which these systems form and evolve toward the regulated coevolution observed in the local Universe.

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BibTeX RIS

BibTeX

@misc{sharma2026halodriven,
  title = {{Halo-driven Origin and Evolution of Overmassive Black Holes and Little Red Dots}},
  author = {Ritik Sharma and Mahavir Sharma},
  howpublished = {arXiv},
  year = {2026},
  month = sep,
  doi = {10.48550/arxiv.2605.16485},
  eprint = {2605.16485},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2605.16485},
}

RIS

TY  - UNPB
TI  - Halo-driven Origin and Evolution of Overmassive Black Holes and Little Red Dots
AU  - Ritik Sharma
AU  - Mahavir Sharma
PY  - 2026
DA  - 2026/09/05
PB  - arXiv
DO  - 10.48550/arxiv.2605.16485
UR  - https://arxiv.org/abs/2605.16485
AB  - We present a theoretical model in which the recently detected overmassive black holes (OBHs), and potentially Little Red Dots (LRDs), arise during a halo-driven transient phase preceding the established coevolution of supermassive black holes (SMBHs) and their host galaxies. In this model, halo gravity drives an early phase of rapid black hole growth, leading to systems in high-redshift haloes that lie above the local scaling relations. As the halo evolves, a transition in halo thermodynamics leads to the onset of a hot, pressure-supported medium that suppresses accretion, reducing the black hole growth rate and driving the system toward the local black hole mass−stellar mass relation. LRDs may represent an observational manifestation of the rapid, halo-driven growth phase, while OBHs trace its direct mass signature. Our model thus provides a unified framework in which these systems form and evolve toward the regulated coevolution observed in the local Universe.
ER  -

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