2024/03/27 by Dominic Agius, Agius, Dominic, Rouven Essig +9 · 5 citations
Physics and Astronomy · #Cosmology and Gravitation Theories #Cosmology and Nongalactic Astrophysics (astro-ph.CO) #Dark Matter and Cosmic Phenomena #FOS: Physical sciences #Galaxies: Formation, Evolution, Phenomena #High Energy Astrophysical Phenomena (astro-ph.HE) #High Energy Physics - Phenomenology (hep-ph)
paper · pdf · doi:10.48550/arxiv.2403.18895
openalex publication_date 2024/03/27 · openalex created_date 2024/03/30 · openalex updated_date 2026/08/01
If present in the early universe, primordial black holes (PBHs) will accrete matter and emit high-energy photons, altering the statistical properties of the Cosmic Microwave Background (CMB). This mechanism has been used to constrain the fraction of dark matter that is in the form of PBHs to be much smaller than unity for PBH masses well above one solar mass. Moreover, the presence of dense dark matter mini-halos around the PBHs has been used to set even more stringent constraints, as these would boost the accretion rates. In this work, we critically revisit CMB constraints on PBHs taking into account the role of the local ionization of the gas around them. We discuss how the local increase in temperature around PBHs can prevent the dark matter mini-halos from strongly enhancing the accretion process, in some cases significantly weakening previously derived CMB constraints. We explore in detail the key ingredients of the CMB bound and derive a conservative limit on the cosmological abundance of massive PBHs.