On the Angular Momentum Transport Efficiency within the Star Constrained from Gravitational-wave Observations

Understand

The LIGO Scientific Collaboration and Virgo Collaboration (LVC) have recently reported in GWTC-2.1 eight additional candidate events with a probability of astrophysical origin greater than 0.5 in the LVC deeper search on O3a running.

• In GWTC-2.1, the majority of the effective inspiral spins ($\chi_{\rm eff}$) show magnitudes consistent with zero, while two (GW190403$_{-}$051519 and GW190805$_{-}$211137) of the eight new events have $\chi_{\rm eff}$ $> 0$ (at 90% credibility).
• We note that GW190403$_{-}$051519 was reported with $\chi_{\rm eff}$ = $0.70^{+0.15}_{-0.27}$ and mass ratio $q$ = $0.25^{+0.54}_{-0.11}$, respectively.
• Assuming a uniform prior probability between 0 and 1 for each black hole's dimensionless spin magnitude, GW190403$_{-}$051519 was reported with the dimensionless spin of the more massive black hole, $\chi_1$ = $0.92^{+0.07}_{-0.22}$.