  Binary interactions, especially mass transfer and mergers, can strongly
influence the evolution of massive stars and change their final properties and
the occurrence of supernovae. Here, we investigate how binary interactions
affect predictions of the diffuse flux of neutrinos. By performing stellar
population syntheses including prescriptions for binary interactions, we show
that the resulting detection rates of the diffuse supernova neutrino background
is enhanced by 15%-20% compared to estimates without binary considerations. A
source of significant uncertainty arises due to the presently sparse knowledge
of the evolution of rapidly rotating carbon-oxygen cores, especially those
created as a result of mergers near the white dwarf to core collapse boundary.
The enhancement effect may be as small as a few percent if the effects of
rotation in postmerger systems are neglected, or as large as 75% if trends are
extrapolated. Our estimates serve to highlight that binary effects can be
important.
