Euclid detectability of pair instability supernovae in binary population synthesis models consistent with merging binary black holes

We infer the expected detection number of pair instability supernovae (PISNe) during the operation of the Euclid space telescope, based on two binary population models that are consistent with binary black holes (BHs) observed by gravitational waves. The two models consider different PISN criteria depending on the $^{12}$C$(\alpha, \gamma)^{16}$O reaction rate. The fiducial and $3\sigma$ models adopt the standard and $3\sigma$-smaller $^{12}$C$(\alpha, \gamma)^{16}$O reaction rate, which predicts that stars with helium core masses $65-135 M_\odot$ and $90-180 M_\odot$ cause PISNe, respectively. Our fiducial model predicts that Euclid detects several Type I or hydrogen-poor PISNe. For the $3\sigma$ model, detection of $\sim 1$ Type I PISN by Euclid is expected if the stellar mass distribution extends to $M_{\max} \sim 600 M_\odot$, but the expected number becomes significantly smaller if $M_{\max} \sim 300 M_\odot$. Thus, we may be able to prove or distinguish the fiducial and $3\sigma$ models by the observed PISN rate. This will help us to constrain the origin of binary BHs and the $^{12}$C$(\alpha, \gamma)^{16}$O reaction rate. PISN ejecta mass estimates from light curves and spectra obtained by follow-up observations would also be important to constrain the $^{12}$C$(\alpha, \gamma)^{16}$O reaction rate.Comment: 4 pages, 4 figures, submitte

Bacillus subtilis variant natto Bacteremia of Gastrointestinal Origin, Japan

We report a case of bacteremia caused by Bacillus subtilis variant natto after a gastrointestinal perforation in a patient in Japan. Genotypic and phenotypic studies of biotin identified B. subtilis var. natto. This case and 3 others in Japan may have been caused by consuming natto (fermented soybeans)