http://arxiv.org/abs/1904.02821
A population of binary black hole mergers has now been observed in gravitational waves by Advanced LIGO and Virgo. The masses of these black holes appear to show evidence for a pile-up between $30$–$45$\,\Msol{} and a cut-off above $\sim 45$\,\Msol. One possible explanation for such a pile-up and subsequent cut-off are pulsational pair-instability supernovae (PPISNe) and pair-instability supernovae (PISNe) in massive stars. We investigate the plausibility of this explanation in the context of isolated massive binaries. We study a population of massive binaries using the rapid population synthesis software COMPAS, incorporating models for PPISNe and PISNe. Our models predict a maximum black hole mass of $40$\,\Msol{}. We expect $\sim 0.5$–$4$\% of all binary black hole mergers at redshift z = 0 will include at least one component that went through a PPISN (with mass $30$–$40$\,\Msol{}), constituting $\sim 5$–$25$\% of binary black hole mergers observed during the first two observing runs of Advanced LIGO and Virgo. Empirical models based on fitting the gravitational-wave mass measurements to a combination of a power law and a Gaussian find a fraction too large to be associated with PPISNe in our models. The rates of PPISNe and PISNe track the low metallicity star formation rate, increasing out to redshift $z = 2$. These predictions may be tested both with future gravitational-wave observations and with observations of superluminous supernovae.
S. Stevenson, M. Sampson, J. Powell, et. al.
Mon, 8 Apr 19
10/45
Comments: 14 pages, 8 figures, submitted to ApJ