Deep follow-up for gravitational-wave inference: a case study with GW151226

Understand

New analyses of gravitational wave events raise questions about the nature of some events.

• For example, LIGO--Virgo--KAGRA initially determined GW151226 to be a merger with a mass-ratio $q\approx0.5$ and effective inspiral spin $\chi_{\text{eff}}\approx 0.2$.
• However, recent works offer an alternative picture: GW151226 is a lower-mass-ratio event $q \approx 0.3$ with slightly higher spin $\chi_{\text{eff}}\approx 0.3$.
• This discrepancy has been challenging to resolve as a wide range of differences are employed for each analysis.