Ultradense Dark Matter Halos with Poisson Noise from Stellar-Mass Primordial Black Holes

TL;DR

This paper explores how Poisson noise from stellar-mass primordial black holes influences the formation and distribution of ultradense dark matter halos, highlighting the dependence on PBH mass, fraction, and model parameters.

Contribution

It introduces a modified power spectrum accounting for PBH-induced Poisson noise and analyzes its effects on UDMH formation, considering realistic halo mass functions.

Findings

Poisson noise from PBHs enhances small-scale density fluctuations.

Higher PBH mass shifts UDMH mass function toward larger masses.

Realistic halo models predict higher UDMH abundance than Press-Schechter.

Abstract

In this work, we investigate the impact of Poisson noise from stellar-mass primordial black holes (PBHs) on the formation of ultradense dark matter halos (UDMHs). Our findings reveal that the discrete spatial distribution of PBHs significantly enhances small-scale density fluctuations, particularly for massive stellar-mass PBHs. Our results indicate that the modified power spectrum, incorporating both adiabatic and isocurvature contributions from PBH-induced Poisson noise, strongly depends on PBH mass and fraction. Specifically, increasing PBH mass shifts the differential mass function of UDMHs toward higher masses, while variations in the suppression parameter $n$ modulate the efficiency of UDMH formation at small scales. For lower values of $n$, our findings show a significant boost in UDMH abundance, favoring multi-component dark matter scenarios. Conversely, at higher values of $n$, the predicted UDMH distributions align more closely with single-component models dominated by stellar-mass PBHs. Furthermore, our analysis demonstrates that more realistic halo mass functions, which account for angular momentum and dynamical friction, consistently predict higher UDMH abundances compared to traditional Press-Schechter formalism.