Effect of Primordial Black Holes on the Cosmic Microwave Background and Cosmological Parameter Estimates

By M. Ricotti, Jeremiah P. Ostriker, K. Mack. 2007

367 citations recorded by the source corpus.

We investigate the effect of nonevaporating primordial black holes (PBHs) on the ionization and thermal history of the universe. X-rays emitted by gas accretion onto PBHs modify the cosmic recombination history, producing measurable effects on the spectrum and anisotropies of the cosmic microwave background (CMB). Using the third-year WMAP data and COBE FIRAS data we improve existing upper limits on the abundance of PBHs with masses >0.1 M☉ by several orders of magnitude. The new upper limits still allow PBHs to be important for the origin of supermassive black holes and ultraluminous X-ray sources. Fitting WMAP3 data with cosmological models that do not allow for nonstandard recombination histories, as produced by PBHs or other early energy sources, may lead to an underestimate of the best-fit values of the amplitude of linear density fluctuations (σ8) and the scalar spectral index (ns). Cosmological parameter estimates are affected because models with PBHs allow for larger values of the Thomson scattering optical depth, whose correlation with other parameters may not be correctly taken into account when PBHs are ignored. Values of τe ∼ 0.2, ns ∼ 1, and σ8 ∼ 0.9 are allowed at 95% CF. This result may relieve recent tension between WMAP3 data and clusters data on the value of σ8. PBHs may increase the primordial molecular hydrogen abundance by up to 2 orders of magnitude, this promoting cooling and star formation. The suppression of galaxy formation due to X-ray heating is negligible for models consistent with the CMB data. Thus, the formation rate of the first galaxies and stars would be enhanced by a population of PBHs.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/69a2cd97c8af3905341794256e6fb69220542aa2

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Citations in the corpus

A fresh look at linear cosmological constraints on a decaying Dark Matter component (2016, background): “[48]), which however could be evaded for instance if the current BH population is much more massive than the initial one, due to a rich merger history [47].”
A Brief Review on Primordial Black Holes as Dark Matter (2021, background): “Although early CMB analyses (Ricotti et al., 2008) found very stringent bounds on the allowed abundance of accreting PBHs, later works revisited these computations and found much milder constraints (Horowitz, 2016; Ali-Haïmoud and Kamionkowski, 2017).”
Generating PBHs and small-scale GWs in two-field models of inflation (2020, background): “We do not show constraints from long-livedness of white dwarfs (WD) [86], the presence of neutron stars in globular clusters around M ∼ 10−13M [87] and femtolensing around M ∼ 10−15M [88] since they have been contested in the literature, see e.”
Two populations of LIGO-Virgo black holes (2020, background): “If PBHs are not the only form of DM, which they cannot be in the solar mass range [13], then PBHs are decorated by compact DM halos [43, 44] which deepen the effective potential well and enhance the accretion rate.”
Primordial Black Holes as Dark Matter: Recent Developments (2020, methodology): “Later an improved analysis was provided by Ricotti and colleagues [199–201].”
Formation of Supermassive Black Hole Seeds (2016, background): “Primordial black holes may have born during the early stages of Big Bang but there is no observational evidence for their existence (Alcock et al. 2000; Afshordi et al. 2003; Tisserand et al. 2007; Ricotti et al. 2008).”
Solving puzzles of GW150914 by primordial black holes (2016, background): “Note that CMB constraints from early accretion onto PBH shown in the analogous plot [39] are model-dependent and should be treated with caution.”
CONSTRAINTS ON MACHO DARK MATTER FROM COMPACT STELLAR SYSTEMS IN ULTRA-FAINT DWARF GALAXIES (2016, background): “The only constraints on a population of MACHOs between ∼30 M⊙ and ∼100 M⊙, however, currently come from limits on spectral distortions of the cosmic microwave background (CMB): black holes may have accreted during the early Universe, leaving an imprint on the CMB (Ricotti et al. 2008).”
Primordial black holes confront LIGO/Virgo data: current situation (2020, methodology): “[9] might be considered as an optimistic choice that assumes a non-negligible fraction of PBHs which keeps accreting significantly even after structure formation, whereas larger values of the cut-off, e.”