Current observations of binary black-hole ({BBH}) merger events show support
for a feature in the primary BH-mass distribution at
βΌ35Mββ, previously interpreted as a signature of
pulsational pair-instability (PPISN) supernovae. Such supernovae are expected
to map a wide range of pre-supernova carbon-oxygen (CO) core masses to a narrow
range of BH masses, producing a peak in the BH mass distribution. However,
recent numerical simulations place the mass location of this peak above
50Mββ. Motivated by uncertainties in the progenitor's
evolution and explosion mechanism, we explore how modifying the distribution of
BH masses resulting from PPISN affects the populations of gravitational-wave
(GW) and electromagnetic (EM) transients. To this end, we simulate populations
of isolated {BBH} systems and combine them with cosmic star-formation rates.
Our results are the first cosmological BBH-merger predictions made using the
\textsc{binary\_c} rapid population synthesis framework. We find that our
fiducial model does not match the observed GW peak. We can only explain the
35Mββ peak with PPISNe by shifting the expected CO core-mass
range for PPISN downwards by βΌ15Mββ. Apart from being
in tension with state-of-the art stellar models, we also find that this is
likely in tension with the observed rate of hydrogen-less super-luminous
supernovae. Conversely, shifting the mass range upward, based on recent stellar
models, leads to a predicted third peak in the BH mass function at
βΌ64Mββ. Thus we conclude that the
βΌ35Mββ feature is unlikely to be related to PPISNe.Comment: Accepted for publication in MNRAS. 19 pages, 8 figures includings
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