Bondi-Hoyle-Lyttleton accretion onto ultra dense dark matter halos and direct collapse black holes

Fuente: arXiv
Saved in:
Bibliographic Details
Main Authors: Subramanian, Kandaswamy, Phookun, Bikram
Format: Preprint
Published: 2026
Subjects:
Online Access:
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1866911551919751168
author Subramanian, Kandaswamy
Phookun, Bikram
author_facet Subramanian, Kandaswamy
Phookun, Bikram
contents We suggest a formation scenario of black holes with intermediate mass $\sim 10^3 M_\odot$, by post recombination Bondi-Hoyle-Lyttleton accretion into ultra dense dark matter halos (UDMH) of $\sim 10^5 M_\odot$, which have formed around the recombination epoch. Such UDMH can result from rare curvature fluctuations on small scales whose amplitude is still well below the current Cosmic Microwave Background (CMB) spectral distortion limits. Gas accreted by the UDMH is heated to virial temperatures above which atomic cooling is efficient, cools rapidly to about $\sim 8000$ K and collapses on the free fall time of few $10^4$ yr to the halo core, until supported by rotation. Further fragmentation due to molecular cooling is prevented by the suppression of $H_2$ molecule formation by the CMB photons at redshifts $z> 200-400$. We find that the rotationally supported gas disk will be compact and massive enough to undergo self-gravitational instability in some cases, plausibly where accretion is into a nearly spherical UDMH which has formed from a rare peak in the density field. This results in a further, rapid transfer of mass inwards due to viscous forces and gravitational torques leading to the formation of a supermassive star and/or black hole of about $10^3 M_\odot$ at redshifts of a few hundred. Such intermediate mass black holes formed at high redshifts can have a large-enough abundance to seed the first super massive black holes and help explain the abundance of active galaxies detected now at increasingly larger redshifts by the James Webb Space Telescope.
format Preprint
id arxiv_https___arxiv_org_abs_2601_02104
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Bondi-Hoyle-Lyttleton accretion onto ultra dense dark matter halos and direct collapse black holes
Subramanian, Kandaswamy
Phookun, Bikram
Cosmology and Nongalactic Astrophysics
Astrophysics of Galaxies
We suggest a formation scenario of black holes with intermediate mass $\sim 10^3 M_\odot$, by post recombination Bondi-Hoyle-Lyttleton accretion into ultra dense dark matter halos (UDMH) of $\sim 10^5 M_\odot$, which have formed around the recombination epoch. Such UDMH can result from rare curvature fluctuations on small scales whose amplitude is still well below the current Cosmic Microwave Background (CMB) spectral distortion limits. Gas accreted by the UDMH is heated to virial temperatures above which atomic cooling is efficient, cools rapidly to about $\sim 8000$ K and collapses on the free fall time of few $10^4$ yr to the halo core, until supported by rotation. Further fragmentation due to molecular cooling is prevented by the suppression of $H_2$ molecule formation by the CMB photons at redshifts $z> 200-400$. We find that the rotationally supported gas disk will be compact and massive enough to undergo self-gravitational instability in some cases, plausibly where accretion is into a nearly spherical UDMH which has formed from a rare peak in the density field. This results in a further, rapid transfer of mass inwards due to viscous forces and gravitational torques leading to the formation of a supermassive star and/or black hole of about $10^3 M_\odot$ at redshifts of a few hundred. Such intermediate mass black holes formed at high redshifts can have a large-enough abundance to seed the first super massive black holes and help explain the abundance of active galaxies detected now at increasingly larger redshifts by the James Webb Space Telescope.
title Bondi-Hoyle-Lyttleton accretion onto ultra dense dark matter halos and direct collapse black holes
topic Cosmology and Nongalactic Astrophysics
Astrophysics of Galaxies
url https://arxiv.org/abs/2601.02104