GW200115: a non-spinning black hole -- neutron star merger

Understand

GW200115 was the second merger of a black hole and a neutron star confidently detected through gravitational waves.

• Inference on the signal allows for a large black hole spin misaligned with the orbital angular momentum, but shows little support for aligned spin values.
• We show that this is a natural consequence of measuring the parameters of a black hole -- neutron star binary with non-spinning components while assuming the priors used in the LIGO-Virgo-KAGRA analysis.
• We suggest that, a priori, a non-spinning binary is more consistent with current astrophysical understanding.