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How Do Primordial Black Holes Change the Halo Mass Function and Structure?

Authors :
Saiyang Zhang
Volker Bromm
Boyuan Liu
Source :
The Astrophysical Journal, Vol 975, Iss 1, p 139 (2024)
Publication Year :
2024
Publisher :
IOP Publishing, 2024.

Abstract

We examine the effects of massive primordial black holes (PBHs) on cosmic structure formation, employing both a semianalytical approach and cosmological simulations. Our simulations incorporate PBHs with a monochromatic mass distribution centered around 10 ^6 M _⊙ , constituting a fraction of 10 ^−2 to 10 ^−4 of the dark matter (DM) in the Universe, with the remainder being collisionless particle DM. Additionally, we conduct a ΛCDM simulation for comparative analysis with runs that include PBHs. At smaller scales, halos containing PBHs exhibit similar density and velocity dispersion profiles to those without PBHs. Conversely, at larger scales, PBHs can expedite the formation of massive halos and reside at their centers owing to the “seed effect.” To analyze the relative distribution of PBH host halos compared to non-PBH halos, we apply nearest neighbor statistics. Our results suggest that PBH host halos, through gravitational influence, significantly impact the structure formation process, compared to the ΛCDM case, by attracting and engulfing nearby newly formed minihalos. Should PBHs constitute a fraction of DM significantly larger than ∼10 ^−3 , almost all newly formed halos will be absorbed by PBH-seeded halos. Consequently, our simulations predict a bimodal feature in the halo mass function, with most of the massive halos containing at least one PBH at their core and the rest being less massive non-PBH halos.

Details

Language :
English
ISSN :
15384357
Volume :
975
Issue :
1
Database :
Directory of Open Access Journals
Journal :
The Astrophysical Journal
Publication Type :
Academic Journal
Accession number :
edsdoj.3face07bd1dd40b1a71acf8c660f2f61
Document Type :
article
Full Text :
https://doi.org/10.3847/1538-4357/ad7b0d