A new spin on LIGO-Virgo binary black holes

Gravitational waves from binary black holes have the potential to yield information on both their masses and spins. While the component masses are usually individually resolvable, a measurement of the component spins is generally elusive. This is partially a consequence of asking about the spins of the most and least massive objects in each binary, a question which becomes ill-defined for equal-mass systems. In this talk, I propose to ask a different question of the data: what are the spins of the most- and least-spinning objects in the binary? Using both simulated systems and the current gravitational-wave events detected by the LIGO-Virgo Collaboration, I will show that this can significantly improve estimates of the individual spins—especially for binary systems with comparable masses—and yield interesting constraints at the population level.