Cosmic microwave background bounds on primordial black holes including dark matter halo accretion

Pasquale D. Serpico (1) , Vivian Poulin (2) , Derek Inman , Kazunori Kohri

1 LAPTH - Laboratoire d'Annecy-le-Vieux de Physique Théorique
2 LUPM - Laboratoire Univers et Particules de Montpellier

Even if massive (10M⊙≲M≲104M⊙) primordial black holes (PBHs) can only account for a small fraction of the dark matter (DM) in the universe, they may still be responsible for a sizable fraction of the coalescence events measured by LIGO/Virgo, and/or act as progenitors of the supermassive black holes (SMBHs) observed already at high redshift (z≳6). In the presence of a dominant, non-PBH DM component, the bounds set by CMB via an altered ionization history are modified. We revisit the cosmological accretion of a DM halo around PBHs via toy models and dedicated numerical simulations, deriving updated CMB bounds which also take into account the last Planck data release. We prove that these constraints dominate over other constraints available in the literature at masses M≳20–50M⊙ (depending on uncertainty in accretion physics), reaching the level fPBH<3×10−9 around M∼104M⊙. These tight bounds are nonetheless consistent with the hypothesis of a primordial origin of the SMBH massive seeds.

Mots clés: black hole: primordial; dark matter: halo; dark matter: accretion; redshift: high; cosmic background radiation: power spectrum; numerical calculations; coalescence; ionization; toy model; history; satellite: Planck; VIRGO; LIGO

Domaines: Astrophysique [astro-ph]

Pasquale D. Serpico, Vivian Poulin, Derek Inman, Kazunori Kohri. Cosmic microwave background bounds on primordial black holes including dark matter halo accretion. Phys.Rev.Res., 2020, 2 (2), pp.023204. ⟨10.1103/PhysRevResearch.2.023204⟩. ⟨hal-02518035⟩