Bayesian Evidence for Both Astrophysical and Primordial Black Holes:
  Mapping the GWTC-2 Catalog to Third-Generation Detectors
  We perform a hierarchical Bayesian analysis of the GWTC-2 catalog to
investigate the mixed scenario in which the merger events are explained by
black holes of both astrophysical and primordial origin. For the astrophysical
scenario we adopt the phenomenological model used by the LIGO/Virgo
collaboration and we include the correlation between different parameters
inferred from data, the role of the spins in both the primordial and
astrophysical scenarios, and the impact of accretion in the primordial
scenario. Our best-fit mixed model has a strong statistical evidence relative
to the single-population astrophysical model, thus supporting the coexistence
of populations of black-hole mergers of two different origins. In particular,
our results indicate that the astrophysical mergers account for roughly four
times the number of primordial black hole events and predict that
third-generation detectors, such as the Einstein Telescope and Cosmic Explorer,
should detect up to hundreds of mergers from primordial black hole binaries at
redshift $z\gtrsim30$.
